Image coding using lexicographic coding order with floating block-partitioning

Decoding image data using lexicographic coding order with floating block-partitioning includes obtaining, from an encoded bitstream, encoded data for a defined portion of a frame, generating a reconstructed frame by decoding the encoded data, and outputting the reconstructed frame for presentation to a user. Decoding the encoded data using lexicographic coding order with floating block-partitioning includes decoding, from the encoded data, block dimension data for respective blocks from the plurality of blocks in lexicographic coding order, determining block location data for the respective blocks from the plurality of blocks in lexicographic coding order, generating reconstructed block data for the respective blocks from the plurality of blocks using the block dimension data and the block location data by decoding, from the encoded data, image content data for the respective blocks from the plurality of blocks, and including the reconstructed block data in the reconstructed frame.

BACKGROUND

Digital images and video can be used, for example, on the internet, for remote business meetings via video conferencing, high definition video entertainment, video advertisements, or sharing of user-generated content. Due to the large amount of data involved in transferring and processing image and video data, high-performance compression may be advantageous for transmission and storage. Accordingly, it would be advantageous to provide high-resolution image and video transmitted over communications channels having limited bandwidth, such as image and video coding using lexicographic coding order with floating block-partitioning.

SUMMARY

This application relates to encoding and decoding of image data, video stream data, or both for transmission or storage. Disclosed herein are aspects of systems, methods, and apparatuses for encoding and decoding using lexicographic coding order with floating block-partitioning.

An aspect is a method for image coding using lexicographic coding order with floating block-partitioning. Image coding using lexicographic coding order with floating block-partitioning may include obtaining, from an encoded bitstream, encoded data for a defined portion of a frame, generating, by a processor, a reconstructed frame by decoding the encoded data using lexicographic coding order with floating block-partitioning, wherein the defined portion includes a plurality of blocks of pixels, and outputting the reconstructed frame for presentation to a user. Decoding the encoded data using lexicographic coding order with floating block-partitioning may include decoding, from the encoded data, block dimension data for respective blocks from the plurality of blocks in lexicographic coding order, determining block location data for the respective blocks from the plurality of blocks in lexicographic coding order, generating reconstructed block data for the respective blocks from the plurality of blocks using the block dimension data and the block location data by decoding, from the encoded data, image content data for the respective blocks from the plurality of blocks, and including the reconstructed block data in the reconstructed frame.

Another aspect is an apparatus for image coding using lexicographic coding order with floating block-partitioning. The apparatus may include a processor configured to obtain, from an encoded bitstream, encoded data for a defined portion of a frame, generate a reconstructed frame by decoding the encoded data using lexicographic coding order with floating block-partitioning, wherein the defined portion includes a plurality of blocks of pixels, and output the reconstructed frame for presentation to a user. Decoding the encoded data using lexicographic coding order with floating block-partitioning includes, decoding, from the encoded data, block dimension data for respective blocks from the plurality of blocks in lexicographic coding order, determining block location data for the respective blocks from the plurality of blocks in lexicographic coding order, generating reconstructed block data for the respective blocks from the plurality of blocks using the block dimension data and the block location data by decoding, from the encoded data, image content data for the respective blocks from the plurality of blocks, including the reconstructed block data in the reconstructed frame.

Another aspect is a method for image coding using lexicographic coding order with floating block-partitioning. Image coding using lexicographic coding order with floating block-partitioning may include obtaining, from an encoded bitstream, an encoded tile header for a tile from an image, decoding, from the encoded tile header, block dimensions for a first block, other than a sub-block, wherein the block dimensions for the first block differ from block dimensions for an adjacent block, other than a sub-block, from the tile, identifying the first block as a current block, determining block location data for the current block in accordance with block location constraints, obtaining, from the encoded bitstream, encoded block data for the current block, generating reconstructed block data for the current block using the block dimensions and the block location data by decoding the encoded block data, including the reconstructed block data in a reconstructed tile, including the reconstructed tile in a reconstructed image, outputting the reconstructed image for presentation to a user.

Variations in these and other aspects will be described in additional detail hereafter.

DETAILED DESCRIPTION

Image and video compression schemes may include breaking an image, or frame, into smaller portions, such as blocks, and generating an output bitstream using techniques to minimize the bandwidth utilization of the information included for each block in the output. In some implementations, the information included for each block in the output may be limited by reducing spatial redundancy, reducing temporal redundancy, or a combination thereof. For example, temporal or spatial redundancies may be reduced by predicting a frame, or a portion thereof, based on information available to both the encoder and decoder, and including information representing a difference, or residual, between the predicted frame and the original frame in the encoded bitstream. The residual information may be further compressed by transforming the residual information into transform coefficients, quantizing the transform coefficients, and entropy coding the quantized transform coefficients. Other coding information, such as motion information, may be included in the encoded bitstream, which may include transmitting differential information based on predictions of the encoding information, which may be entropy coded to further reduce the corresponding bandwidth utilization. An encoded bitstream can be decoded to reconstruct the blocks and the source images from the limited information.

In some implementations, image and video coding may include partitioning a frame using trellised block partitioning wherein the frame is partitioned in accordance with a grid or trellis of maximum size blocks aligned in rows and columns. The maximum size blocks may be partitioned into sub-blocks. The available block sizes may be limited by the maximum size block. Block sizes greater than the maximum block size in a dimension may be unavailable. Block locations may be subject to a trellising constraint to be aligned with the trellis of maximum size blocks. Blocks crossing boundaries of the maximum block size trellis may be unavailable. The maximum size blocks may be coded in a defined block coding order, such as raster order.

Implementations of image and video coding using lexicographic coding order with floating block-partitioning may increase the available block sizes and block locations, which may reduce bandwidth utilization relative to trellised block partitioning. Implementations of image and video coding using lexicographic coding order with floating block-partitioning may signal block dimensions in accordance with a lexicographic coding order, which may differ from the defined block coding order used with trellised block partitioning. The image content for the respective blocks may be signaled in an order that differs from the order for signaling the block dimensions.

FIG. 1is a diagram of a computing device100in accordance with implementations of this disclosure. The computing device100shown includes a memory110, a processor120, a user interface (UI)130, an electronic communication unit140, a sensor150, a power source160, and a bus170. As used herein, the term “computing device” includes any unit, or a combination of units, capable of performing any method, or any portion or portions thereof, disclosed herein.

The computing device100may be a stationary computing device, such as a personal computer (PC), a server, a workstation, a minicomputer, or a mainframe computer; or a mobile computing device, such as a mobile telephone, a personal digital assistant (PDA), a laptop, or a tablet PC. Although shown as a single unit, any one element or elements of the computing device100can be integrated into any number of separate physical units. For example, the user interface130and processor120can be integrated in a first physical unit and the memory110can be integrated in a second physical unit.

The memory110can include any non-transitory computer-usable or computer-readable medium, such as any tangible device that can, for example, contain, store, communicate, or transport data112, instructions114, an operating system116, or any information associated therewith, for use by or in connection with other components of the computing device100. The non-transitory computer-usable or computer-readable medium can be, for example, a solid state drive, a memory card, removable media, a read-only memory (ROM), a random-access memory (RAM), any type of disk including a hard disk, a floppy disk, an optical disk, a magnetic or optical card, an application-specific integrated circuits (ASICs), or any type of non-transitory media suitable for storing electronic information, or any combination thereof.

Although shown as a single unit, the memory110may include multiple physical units, such as one or more primary memory units, such as random-access memory units, one or more secondary data storage units, such as disks, or a combination thereof. For example, the data112, or a portion thereof, the instructions114, or a portion thereof, or both, may be stored in a secondary storage unit and may be loaded or otherwise transferred to a primary storage unit in conjunction with processing the respective data112, executing the respective instructions114, or both. In some implementations, the memory110, or a portion thereof, may be removable memory.

The data112can include information, such as input audio data, encoded audio data, decoded audio data, or the like. The instructions114can include directions, such as code, for performing any method, or any portion or portions thereof, disclosed herein. The instructions114can be realized in hardware, software, or any combination thereof. For example, the instructions114may be implemented as information stored in the memory110, such as a computer program, that may be executed by the processor120to perform any of the respective methods, algorithms, aspects, or combinations thereof, as described herein.

Although shown as included in the memory110, in some implementations, the instructions114, or a portion thereof, may be implemented as a special purpose processor, or circuitry, that can include specialized hardware for carrying out any of the methods, algorithms, aspects, or combinations thereof, as described herein. Portions of the instructions114can be distributed across multiple processors on the same machine or different machines or across a network such as a local area network, a wide area network, the Internet, or a combination thereof.

The processor120can include any device or system capable of manipulating or processing a digital signal or other electronic information now-existing or hereafter developed, including optical processors, quantum processors, molecular processors, or a combination thereof. For example, the processor120can include a special purpose processor, a central processing unit (CPU), a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessor in association with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a programmable logic array, programmable logic controller, microcode, firmware, any type of integrated circuit (IC), a state machine, or any combination thereof. As used herein, the term “processor” includes a single processor or multiple processors.

The user interface130can include any unit capable of interfacing with a user, such as a virtual or physical keypad, a touchpad, a display, a touch display, a speaker, a microphone, a video camera, a sensor, or any combination thereof. For example, the user interface130may be an audio-visual display device, and the computing device100may present audio, such as decoded audio, using the user interface130audio-visual display device, such as in conjunction with displaying video, such as decoded video. Although shown as a single unit, the user interface130may include one or more physical units. For example, the user interface130may include an audio interface for performing audio communication with a user, and a touch display for performing visual and touch-based communication with the user.

The electronic communication unit140can transmit, receive, or transmit and receive signals via a wired or wireless electronic communication medium180, such as a radio frequency (RF) communication medium, an ultraviolet (UV) communication medium, a visible light communication medium, a fiber optic communication medium, a wireline communication medium, or a combination thereof. For example, as shown, the electronic communication unit140is operatively connected to an electronic communication interface142, such as an antenna, configured to communicate via wireless signals.

Although the electronic communication interface142is shown as a wireless antenna inFIG. 1, the electronic communication interface142can be a wireless antenna, as shown, a wired communication port, such as an Ethernet port, an infrared port, a serial port, or any other wired or wireless unit capable of interfacing with a wired or wireless electronic communication medium180. AlthoughFIG. 1shows a single electronic communication unit140and a single electronic communication interface142, any number of electronic communication units and any number of electronic communication interfaces can be used.

The sensor150may include, for example, an audio-sensing device, a visible light-sensing device, a motion sensing device, or a combination thereof. For example,100the sensor150may include a sound-sensing device, such as a microphone, or any other sound-sensing device now existing or hereafter developed that can sense sounds in the proximity of the computing device100, such as speech or other utterances, made by a user operating the computing device100. In another example, the sensor150may include a camera, or any other image-sensing device now existing or hereafter developed that can sense an image such as the image of a user operating the computing device. Although a single sensor150is shown, the computing device100may include a number of sensors150. For example, the computing device100may include a first camera oriented with a field of view directed toward a user of the computing device100and a second camera oriented with a field of view directed away from the user of the computing device100.

The power source160can be any suitable device for powering the computing device100. For example, the power source160can include a wired external power source interface; one or more dry cell batteries, such as nickel-cadmium (NiCad), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion); solar cells; fuel cells; or any other device capable of powering the computing device100. Although a single power source160is shown inFIG. 1, the computing device100may include multiple power sources160, such as a battery and a wired external power source interface.

Although shown as separate units, the electronic communication unit140, the electronic communication interface142, the user interface130, the power source160, or portions thereof, may be configured as a combined unit. For example, the electronic communication unit140, the electronic communication interface142, the user interface130, and the power source160may be implemented as a communications port capable of interfacing with an external display device, providing communications, power, or both.

One or more of the memory110, the processor120, the user interface130, the electronic communication unit140, the sensor150, or the power source160, may be operatively coupled via a bus170. Although a single bus170is shown inFIG. 1, a computing device100may include multiple buses. For example, the memory110, the processor120, the user interface130, the electronic communication unit140, the sensor150, and the bus170may receive power from the power source160via the bus170. In another example, the memory110, the processor120, the user interface130, the electronic communication unit140, the sensor150, the power source160, or a combination thereof, may communicate data, such as by sending and receiving electronic signals, via the bus170.

Although not shown separately inFIG. 1, one or more of the processor120, the user interface130, the electronic communication unit140, the sensor150, or the power source160may include internal memory, such as an internal buffer or register. For example, the processor120may include internal memory (not shown) and may read data112from the memory110into the internal memory (not shown) for processing.

Although shown as separate elements, the memory110, the processor120, the user interface130, the electronic communication unit140, the sensor150, the power source160, and the bus170, or any combination thereof can be integrated in one or more electronic units, circuits, or chips.

FIG. 2is a diagram of a computing and communications system200in accordance with implementations of this disclosure. The computing and communications system200shown includes computing and communication devices100A,100B,100C, access points210A,210B, and a network220. For example, the computing and communication system200can be a multiple access system that provides communication, such as voice, audio, data, video, messaging, broadcast, or a combination thereof, to one or more wired or wireless communicating devices, such as the computing and communication devices100A,100B,100C. Although, for simplicity,FIG. 2shows three computing and communication devices100A,100B,100C, two access points210A,210B, and one network220, any number of computing and communication devices, access points, and networks can be used.

A computing and communication device100A,100B,100C can be, for example, a computing device, such as the computing device100shown inFIG. 1. For example, the computing and communication devices100A,100B may be user devices, such as a mobile computing device, a laptop, a thin client, or a smartphone, and the computing and communication device100C may be a server, such as a mainframe or a cluster. Although the computing and communication device100A and the computing and communication device100B are described as user devices, and the computing and communication device100C is described as a server, any computing and communication device may perform some or all of the functions of a server, some or all of the functions of a user device, or some or all of the functions of a server and a user device. For example, the server computing and communication device100C may receive, encode, process, store, transmit, or a combination thereof audio data and one or both of the computing and communication device100A and the computing and communication device100B may receive, decode, process, store, present, or a combination thereof the audio data.

Each computing and communication device100A,100B,100C, which may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a personal computer, a tablet computer, a server, consumer electronics, or any similar device, can be configured to perform wired or wireless communication, such as via the network220. For example, the computing and communication devices100A,100B,100C can be configured to transmit or receive wired or wireless communication signals. Although each computing and communication device100A,100B,100C is shown as a single unit, a computing and communication device can include any number of interconnected elements.

Each access point210A,210B can be any type of device configured to communicate with a computing and communication device100A,100B,100C, a network220, or both via wired or wireless communication links180A,180B,180C. For example, an access point210A,210B can include a base station, a base transceiver station (BTS), a Node-B, an enhanced Node-B (eNode-B), a Home Node-B (HNode-B), a wireless router, a wired router, a hub, a relay, a switch, or any similar wired or wireless device. Although each access point210A,210B is shown as a single unit, an access point can include any number of interconnected elements.

The network220can be any type of network configured to provide services, such as voice, data, applications, voice over internet protocol (VoIP), or any other communications protocol or combination of communications protocols, over a wired or wireless communication link. For example, the network220can be a local area network (LAN), wide area network (WAN), virtual private network (VPN), a mobile or cellular telephone network, the Internet, or any other means of electronic communication. The network can use a communication protocol, such as the transmission control protocol (TCP), the user datagram protocol (UDP), the internet protocol (IP), the real-time transport protocol (RTP) the HyperText Transport Protocol (HTTP), or a combination thereof.

The computing and communication devices100A,100B,100C can communicate with each other via the network220using one or more wired or wireless communication links, or via a combination of wired and wireless communication links. For example, as shown the computing and communication devices100A,100B can communicate via wireless communication links180A,180B, and computing and communication device100C can communicate via a wired communication link180C. Any of the computing and communication devices100A,100B,100C may communicate using any wired or wireless communication link, or links. For example, a first computing and communication device100A can communicate via a first access point210A using a first type of communication link, a second computing and communication device100B can communicate via a second access point210B using a second type of communication link, and a third computing and communication device100C can communicate via a third access point (not shown) using a third type of communication link. Similarly, the access points210A,210B can communicate with the network220via one or more types of wired or wireless communication links230A,230B. AlthoughFIG. 2shows the computing and communication devices100A,100B,100C in communication via the network220, the computing and communication devices100A,100B,100C can communicate with each other via any number of communication links, such as a direct wired or wireless communication link.

In some implementations, communications between one or more of the computing and communication devices100A,100B,100C may omit communicating via the network220and may include transferring data via another medium (not shown), such as a data storage device. For example, the server computing and communication device100C may store audio data, such as encoded audio data, in a data storage device, such as a portable data storage unit, and one or both of the computing and communication device100A or the computing and communication device100B may access, read, or retrieve the stored audio data from the data storage unit, such as by physically disconnecting the data storage device from the server computing and communication device100C and physically connecting the data storage device to the computing and communication device100A or the computing and communication device100B.

Other implementations of the computing and communications system200are possible. For example, in an implementation, the network220can be an ad-hoc network and can omit one or more of the access points210A,210B. The computing and communications system200may include devices, units, or elements not shown inFIG. 2. For example, the computing and communications system200may include many more communicating devices, networks, and access points.

FIG. 3is a diagram of a video stream300for use in encoding and decoding in accordance with implementations of this disclosure. A video stream300, such as a video stream captured by a video camera or a video stream generated by a computing device, may include a video sequence310. The video sequence310may include a sequence of adjacent frames320. Although three adjacent frames320are shown, the video sequence310can include any number of adjacent frames320.

Each frame330from the adjacent frames320may represent a single image from the video stream. Although not shown inFIG. 3, a frame330may include one or more segments, tiles, or planes, which may be coded, or otherwise processed, independently, such as in parallel. A frame330may include one or more tiles340. Each of the tiles340may be a rectangular region of the frame that can be coded independently. Each of the tiles340may include respective blocks350. Although not shown inFIG. 3, a block can include pixels. For example, a block can include a 16×16 group of pixels, an 8×8 group of pixels, an 8×16 group of pixels, or any other group of pixels. Unless otherwise indicated herein, the term ‘block’ can include a superblock, a macroblock, a segment, a slice, or any other portion of a frame. A frame, a block, a pixel, or a combination thereof can include display information, such as luminance information, chrominance information, or any other information that can be used to store, modify, communicate, or display the video stream or a portion thereof.

FIG. 4is a block diagram of an encoder400in accordance with implementations of this disclosure. Encoder400can be implemented in a device, such as the computing device100shown inFIG. 1or the computing and communication devices100A,100B,100C shown inFIG. 2, as, for example, a computer software program stored in a data storage unit, such as the memory110shown inFIG. 1. The computer software program can include machine instructions that may be executed by a processor, such as the processor120shown inFIG. 1, and may cause the device to encode video data as described herein. The encoder400can be implemented as specialized hardware included, for example, in computing device100.

The encoder400can encode an input video stream402, such as the video stream300shown inFIG. 3, to generate an encoded (compressed) bitstream404. In some implementations, the encoder400may include a forward path for generating the compressed bitstream404. The forward path may include an intra/inter prediction unit410, a transform unit420, a quantization unit430, an entropy encoding unit440, or any combination thereof. In some implementations, the encoder400may include a reconstruction path (indicated by the broken connection lines) to reconstruct a frame for encoding of further blocks. The reconstruction path may include a dequantization unit450, an inverse transform unit460, a reconstruction unit470, a filtering unit480, or any combination thereof. Other structural variations of the encoder400can be used to encode the video stream402.

For encoding the video stream402, each frame within the video stream402can be processed in units of blocks. Thus, a current block may be identified from the blocks in a frame, and the current block may be encoded.

At the intra/inter prediction unit410, the current block can be encoded using either intra-frame prediction, which may be within a single frame, or inter-frame prediction, which may be from frame to frame. Intra-prediction may include generating a prediction block from samples in the current frame that have been previously encoded and reconstructed. Inter-prediction may include generating a prediction block from samples in one or more previously constructed reference frames. Generating a prediction block for a current block in a current frame may include performing motion estimation to generate a motion vector indicating an appropriate reference portion of the reference frame.

The intra/inter prediction unit410may subtract the prediction block from the current block (raw block) to produce a residual block. The transform unit420may perform a block-based transform, which may include transforming the residual block into transform coefficients in, for example, the frequency domain. Examples of block-based transforms include the Karhunen-Loeve Transform (KLT), the Discrete Cosine Transform (DCT), the Singular Value Decomposition Transform (SVD), and the Asymmetric Discrete Sine Transform (ADST). In an example, the DCT may include transforming a block into the frequency domain. The DCT may include using transform coefficient values based on spatial frequency, with the lowest frequency (i.e. DC) coefficient at the top-left of the matrix and the highest frequency coefficient at the bottom-right of the matrix.

The quantization unit430may convert the transform coefficients into discrete quantum values, which may be referred to as quantized transform coefficients or quantization levels. The quantized transform coefficients can be entropy encoded by the entropy encoding unit440to produce entropy-encoded coefficients. Entropy encoding can include using a probability distribution metric. The entropy-encoded coefficients and information used to decode the block, which may include the type of prediction used, motion vectors, and quantizer values, can be output to the compressed bitstream404. The compressed bitstream404can be formatted using various techniques, such as run-length encoding (RLE) and zero-run coding.

The reconstruction path can be used to maintain reference frame synchronization between the encoder400and a corresponding decoder, such as the decoder500shown inFIG. 5. The reconstruction path may be similar to the decoding process discussed below and may include decoding the encoded frame, or a portion thereof, which may include decoding an encoded block, which may include dequantizing the quantized transform coefficients at the dequantization unit450and inverse transforming the dequantized transform coefficients at the inverse transform unit460to produce a derivative residual block. The reconstruction unit470may add the prediction block generated by the intra/inter prediction unit410to the derivative residual block to create a decoded block. The filtering unit480can be applied to the decoded block to generate a reconstructed block, which may reduce distortion, such as blocking artifacts. Although one filtering unit480is shown inFIG. 4, filtering the decoded block may include loop filtering, deblocking filtering, or other types of filtering or combinations of types of filtering. The reconstructed block may be stored or otherwise made accessible as a reconstructed block, which may be a portion of a reference frame, for encoding another portion of the current frame, another frame, or both, as indicated by the broken line at482. Coding information, such as deblocking threshold index values, for the frame may be encoded, included in the compressed bitstream404, or both, as indicated by the broken line at484.

Other variations of the encoder400can be used to encode the compressed bitstream404. For example, a non-transform-based encoder400can quantize the residual block directly without the transform unit420. In some implementations, the quantization unit430and the dequantization unit450may be combined into a single unit.

FIG. 5is a block diagram of a decoder500in accordance with implementations of this disclosure. The decoder500can be implemented in a device, such as the computing device100shown inFIG. 1or the computing and communication devices100A,100B,100C shown inFIG. 2, as, for example, a computer software program stored in a data storage unit, such as the memory110shown inFIG. 1. The computer software program can include machine instructions that may be executed by a processor, such as the processor120shown inFIG. 1, and may cause the device to decode video data as described herein. The decoder500can be implemented as specialized hardware included, for example, in computing device100.

The decoder500may receive a compressed bitstream502, such as the compressed bitstream404shown inFIG. 4, and may decode the compressed bitstream502to generate an output video stream504. The decoder500may include an entropy decoding unit510, a dequantization unit520, an inverse transform unit530, an intra/inter prediction unit540, a reconstruction unit550, a filtering unit560, or any combination thereof. Other structural variations of the decoder500can be used to decode the compressed bitstream502.

The entropy decoding unit510may decode data elements within the compressed bitstream502using, for example, Context Adaptive Binary Arithmetic Decoding, to produce a set of quantized transform coefficients. The dequantization unit520can dequantize the quantized transform coefficients, and the inverse transform unit530can inverse transform the dequantized transform coefficients to produce a derivative residual block, which may correspond to the derivative residual block generated by the inverse transform unit460shown inFIG. 4. Using header information decoded from the compressed bitstream502, the intra/inter prediction unit540may generate a prediction block corresponding to the prediction block created in the encoder400. At the reconstruction unit550, the prediction block can be added to the derivative residual block to create a decoded block. The filtering unit560can be applied to the decoded block to reduce artifacts, such as blocking artifacts, which may include loop filtering, deblocking filtering, or other types of filtering or combinations of types of filtering, and which may include generating a reconstructed block, which may be output as the output video stream504.

Other variations of the decoder500can be used to decode the compressed bitstream502. For example, the decoder500can produce the output video stream504without the deblocking filtering unit570.

FIG. 6is a block diagram of a representation of a portion600of a frame, such as the frame330shown inFIG. 3, in accordance with implementations of this disclosure. As shown, the portion600of the frame includes four 64×64 blocks610, in two rows and two columns in a matrix or Cartesian plane. In some implementations, a 64×64 block may be a maximum coding unit, N=64. Each 64×64 block may include four 32×32 blocks620. Each 32×32 block may include four 16×16 blocks630. Each 16×16 block may include four 8×8 blocks640. Each 8×8 block640may include four 4×4 blocks650. Each 4×4 block650may include 16 pixels, which may be represented in four rows and four columns in each respective block in the Cartesian plane or matrix. The pixels may include information representing an image captured in the frame, such as luminance information, color information, and location information. In some implementations, a block, such as a 16×16 pixel block as shown, may include a luminance block660, which may include luminance pixels662; and two chrominance blocks670,680, such as a U or Cb chrominance block670, and a V or Cr chrominance block680. The chrominance blocks670,680may include chrominance pixels690. For example, the luminance block660may include 16×16 luminance pixels662and each chrominance block670,680may include 8×8 chrominance pixels690as shown. Although one arrangement of blocks is shown, any arrangement may be used. AlthoughFIG. 6shows N×N blocks, in some implementations, N×M blocks may be used. For example, 32×64 blocks, 64×32 blocks, 16×32 blocks, 32×16 blocks, or any other size blocks may be used. In some implementations, N×2N blocks, 2N×N blocks, or a combination thereof may be used.

In some implementations, video coding may include ordered block-level coding. Ordered block-level coding may include coding blocks of a frame in an order, such as raster-scan order, wherein blocks may be identified and processed starting with a block in the upper left corner of the frame, or portion of the frame, and proceeding along rows from left to right and from the top row to the bottom row, identifying each block in turn for processing. For example, the 64×64 block in the top row and left column of a frame may be the first block coded and the 64×64 block immediately to the right of the first block may be the second block coded. The second row from the top may be the second row coded, such that the 64×64 block in the left column of the second row may be coded after the 64×64 block in the rightmost column of the first row.

In some implementations, coding a block may include using quad-tree coding, which may include coding smaller block units within a block in raster-scan order. For example, the 64×64 block shown in the bottom left corner of the portion of the frame shown inFIG. 6, may be coded using quad-tree coding wherein the top left 32×32 block may be coded, then the top right 32×32 block may be coded, then the bottom left 32×32 block may be coded, and then the bottom right 32×32 block may be coded. Each 32×32 block may be coded using quad-tree coding wherein the top left 16×16 block may be coded, then the top right 16×16 block may be coded, then the bottom left 16×16 block may be coded, and then the bottom right 16×16 block may be coded. Each 16×16 block may be coded using quad-tree coding wherein the top left 8×8 block may be coded, then the top right 8×8 block may be coded, then the bottom left 8×8 block may be coded, and then the bottom right 8×8 block may be coded. Each 8×8 block may be coded using quad-tree coding wherein the top left 4×4 block may be coded, then the top right 4×4 block may be coded, then the bottom left 4×4 block may be coded, and then the bottom right 4×4 block may be coded. In some implementations, 8×8 blocks may be omitted for a 16×16 block, and the 16×16 block may be coded using quad-tree coding wherein the top left 4×4 block may be coded, then the other 4×4 blocks in the 16×16 block may be coded in raster-scan order.

In some implementations, video coding may include compressing the information included in an original, or input, frame by, for example, omitting some of the information in the original frame from a corresponding encoded frame. For example, coding may include reducing spectral redundancy, reducing spatial redundancy, reducing temporal redundancy, or a combination thereof.

In some implementations, reducing spectral redundancy may include using a color model based on a luminance component (Y) and two chrominance components (U and V or Cb and Cr), which may be referred to as the YUV or YCbCr color model, or color space. Using the YUV color model may include using a relatively large amount of information to represent the luminance component of a portion of a frame and using a relatively small amount of information to represent each corresponding chrominance component for the portion of the frame. For example, a portion of a frame may be represented by a high-resolution luminance component, which may include a 16×16 block of pixels, and by two lower resolution chrominance components, each of which represents the portion of the frame as an 8×8 block of pixels. A pixel may indicate a value, for example, a value in the range from 0 to 255, and may be stored or transmitted using, for example, eight bits. Although this disclosure is described in reference to the YUV color model, any color model may be used.

In some implementations, reducing spatial redundancy may include transforming a block into the frequency domain using, for example, a discrete cosine transform (DCT). For example, a unit of an encoder, such as the transform unit420shown inFIG. 4, may perform a DCT using transform coefficient values based on spatial frequency.

In some implementations, reducing temporal redundancy may include using similarities between frames to encode a frame using a relatively small amount of data based on one or more reference frames, which may be previously encoded, decoded, and reconstructed frames of the video stream. For example, a block or pixel of a current frame may be similar to a spatially corresponding block or pixel of a reference frame. In some implementations, a block or pixel of a current frame may be similar to block or pixel of a reference frame at a different spatial location and reducing temporal redundancy may include generating motion information indicating the spatial difference, or translation, between the location of the block or pixel in the current frame and corresponding location of the block or pixel in the reference frame.

In some implementations, reducing temporal redundancy may include identifying a portion of a reference frame that corresponds to a current block or pixel of a current frame. For example, a reference frame, or a portion of a reference frame, which may be stored in memory, may be searched to identify a portion for generating a prediction to use for encoding a current block or pixel of the current frame with maximal efficiency. For example, the search may identify a portion of the reference frame for which the difference in pixel values between the current block and a prediction block generated based on the portion of the reference frame is minimized and may be referred to as motion searching. In some implementations, the portion of the reference frame searched may be limited. For example, the portion of the reference frame searched, which may be referred to as the search area, may include a limited number of rows of the reference frame. In an example, identifying the portion of the reference frame for generating a prediction may include calculating a cost function, such as a sum of absolute differences (SAD), between the pixels of portions of the search area and the pixels of the current block.

In some implementations, the spatial difference between the location of the portion of the reference frame for generating a prediction in the reference frame and the current block in the current frame may be represented as a motion vector. The difference in pixel values between the prediction block and the current block may be referred to as differential data, residual data, a prediction error, or as a residual block. In some implementations, generating motion vectors may be referred to as motion estimation, and a pixel of a current block may be indicated based on location using Cartesian coordinates as fx,y. Similarly, a pixel of the search area of the reference frame may be indicated based on location using Cartesian coordinates as rx,y. A motion vector (MV) for the current block may be determined based on, for example, a SAD between the pixels of the current frame and the corresponding pixels of the reference frame.

Although described herein with reference to matrix or Cartesian representation of a frame for clarity, a frame may be stored, transmitted, processed, or any combination thereof, in any data structure such that pixel values may be efficiently represented for a frame or image. For example, a frame may be stored, transmitted, processed, or any combination thereof, in a two-dimensional data structure such as a matrix as shown, or in a one-dimensional data structure, such as a vector array. In an implementation, a representation of the frame, such as a two-dimensional representation as shown, may correspond to a physical location in a rendering of the frame as an image. For example, a location in the top left corner of a block in the top left corner of the frame may correspond with a physical location in the top left corner of a rendering of the frame as an image.

In some implementations, block-based coding efficiency may be improved by partitioning input blocks into one or more prediction partitions, which may be rectangular, including square, partitions for prediction coding. In some implementations, video coding using prediction partitioning may include selecting a prediction partitioning scheme from among multiple candidate prediction partitioning schemes. For example, in some implementations, candidate prediction partitioning schemes for a 64×64 coding unit may include rectangular size prediction partitions ranging in sizes from 4×4 to 64×64, such as 4×4, 4×8, 8×4, 8×8, 8×16, 16×8, 16×16, 16×32, 32×16, 32×32, 32×64, 64×32, or 64×64. In some implementations, video coding using prediction partitioning may include a full prediction partition search, which may include selecting a prediction partitioning scheme by encoding the coding unit using each available candidate prediction partitioning scheme and selecting the best scheme, such as the scheme that produces the least rate-distortion error.

In some implementations, encoding a video frame may include identifying a prediction partitioning scheme for encoding a current block, such as block610. In some implementations, identifying a prediction partitioning scheme may include determining whether to encode the block as a single prediction partition of maximum coding unit size, which may be 64×64 as shown, or to partition the block into multiple prediction partitions, which may correspond with the sub-blocks, such as the 32×32 blocks620the 16×16 blocks630, or the 8×8 blocks640, as shown, and may include determining whether to partition into one or more smaller prediction partitions. For example, a 64×64 block may be partitioned into four 32×32 prediction partitions. Three of the four 32×32 prediction partitions may be encoded as 32×32 prediction partitions and the fourth 32×32 prediction partition may be further partitioned into four 16×16 prediction partitions. Three of the four 16×16 prediction partitions may be encoded as 16×16 prediction partitions and the fourth 16×16 prediction partition may be further partitioned into four 8×8 prediction partitions, each of which may be encoded as an 8×8 prediction partition. In some implementations, identifying the prediction partitioning scheme may include using a prediction partitioning decision tree.

In some implementations, video coding for a current block may include identifying an optimal prediction coding mode from multiple candidate prediction coding modes, which may provide flexibility in handling video signals with various statistical properties and may improve the compression efficiency. For example, a video coder may evaluate each candidate prediction coding mode to identify the optimal prediction coding mode, which may be, for example, the prediction coding mode that minimizes an error metric, such as a rate-distortion cost, for the current block. In some implementations, the complexity of searching the candidate prediction coding modes may be reduced by limiting the set of available candidate prediction coding modes based on similarities between the current block and a corresponding prediction block. In some implementations, the complexity of searching each candidate prediction coding mode may be reduced by performing a directed refinement mode search. For example, metrics may be generated for a limited set of candidate block sizes, such as 16×16, 8×8, and 4×4, the error metric associated with each block size may be in descending order, and additional candidate block sizes, such as 4×8 and 8×4 block sizes, may be evaluated.

In some implementations, block-based coding efficiency may be improved by partitioning a current residual block into one or more transform partitions, which may be rectangular, including square, partitions for transform coding. In some implementations, video coding using transform partitioning may include selecting a uniform transform partitioning scheme. For example, a current residual block, such as block610, may be a 64×64 block and may be transformed without partitioning using a 64×64 transform.

Although not expressly shown inFIG. 6, a residual block may be transform partitioned using a uniform transform partitioning scheme. For example, a 64×64 residual block may be transform partitioned using a uniform transform partitioning scheme including four 32×32 transform blocks, using a uniform transform partitioning scheme including sixteen 16×16 transform blocks, using a uniform transform partitioning scheme including sixty-four 8×8 transform blocks, or using a uniform transform partitioning scheme including 256 4×4 transform blocks.

In some implementations, video coding using transform partitioning may include identifying multiple transform block sizes for a residual block using multiform transform partition coding. In some implementations, multiform transform partition coding may include recursively determining whether to transform a current block using a current block size transform or by partitioning the current block and multiform transform partition coding each partition. For example, the bottom left block610shown inFIG. 6may be a 64×64 residual block, and multiform transform partition coding may include determining whether to code the current 64×64 residual block using a 64×64 transform or to code the 64×64 residual block by partitioning the 64×64 residual block into partitions, such as four 32×32 blocks620, and multiform transform partition coding each partition. In some implementations, determining whether to transform partition the current block may be based on comparing a cost for encoding the current block using a current block size transform to a sum of costs for encoding each partition using partition size transforms.

FIG. 7is a block diagram of a representation of a portion700of a frame, such as the frame330shown inFIG. 3, in accordance with implementations of this disclosure. As shown, the portion700of the frame includes 16 rows and 32 columns in a matrix or Cartesian plane. Each element701may represent a respective pixel. The pixels may include information representing an image captured in the frame, such as luminance information, color information, and location information. AlthoughFIG. 7shows 16 rows and 32 columns, any cardinality of rows and any cardinality of columns may be used. The portion700may be a frame, a tile, or any other portion of a frame.

Image or video coding may include partitioning a frame, or a portion of a frame, such as the portion700shown inFIG. 7, into blocks of pixels. Partitioning a frame, or a portion of a frame, into blocks of pixels may include restricting or controlling the partitioning in accordance with one or more constraints. The constraints may reduce bandwidth, such as storage, memory, or transmission bandwidth, utilization and may reduce accuracy.

A frame, or a portion of a frame, may be partitioned subject to a maximum block size, or superblock, constraint. For example, 64×64 blocks, such as the 64×64 blocks610shown inFIG. 6, may be maximum block size blocks. Other maximum block sizes, such as 128×128 may be used. A maximum block size constraint may be expressed as a maximum block dimension constraint, which may define a maximum block height and a maximum block width.

Blocks may be constrained to be aligned, such as along block boundaries of the maximum block size blocks. Blocks may have a minimum block size, such as 2×2 blocks, or 4×4 blocks, such as the 4×4 block650shown inFIG. 6. Blocks may be constrained to include multiples of two or four pixels. Blocks may be constrained to be square, such as 32×32 blocks, such as the 32×32 blocks620shown inFIG. 6, 16×16 blocks, such as the 16×16 blocks630shown inFIG. 6, 8×8 blocks, such as the 8×8 blocks640shown inFIG. 6, 4×4 blocks, such as the 4×4 blocks650shown inFIG. 6, or 2×2 blocks. Blocks may be constrained to be rectangular, which may include square blocks, and non-square rectangular blocks, such as 32×64 blocks, 64×32 blocks, 16×32 blocks, 32×16 blocks, 8×16 blocks, 16×8 blocks, 4×8 blocks, 8×4 blocks, 2×4 blocks, or 4×2 blocks. In some implementations, a minimum block size of one pixel, a maximum block size corresponding to the frame size, or a both may be used. The set of block sizes may include block sizes in the range from a minimum block size of one pixel to a maximum block size corresponding to the frame, or tile, size. In some implementations, partitioning a frame, or a portion of a frame, may include using a defined set of available block sizes, which may omit using block sizes that differ from the defined set of available block sizes. A defined set of available block sizes may be a subset of block sizes that omits one or more of the block sizes in the range from a minimum block size of one pixel to a maximum block size corresponding to the frame, or tile, size. In some implementations, block sizes may be defined in the sub-pixel domain, the super-frame domain, or both.

Trellised block partitioning may include partitioning a frame, or a portion of a frame, such as a tile, using a grid or trellis of maximum size blocks aligned in rows and columns (trellising constraint), and may include partitioning the maximum size blocks into sub-blocks (sub-block partitioning), such as shown inFIG. 6. Image or video coding using trellised block partitioning may include encoding, decoding, or both, the blocks in a defined block scan order, such as in raster order. For example, the maximum size blocks may be coded in raster order and the sub-blocks within a respective maximum size block may be coded in raster order or in another order. The sub-blocks of a maximum size block may be coded prior to coding a subsequent, such as adjacent in the defined block order, block.

Image or video coding using floating block-partitioning may be similar to the trellised block partitioning shown inFIG. 6, except as described herein or otherwise clear from context. One or more of the constraints of trellised block partitioning may be relaxed or omitted in floating block-partitioning. For example, floating block-partitioning may omit partitioning using a grid or trellis of maximum size blocks aligned in block-rows and block-columns. In some implementations, floating block-partitioning may include using one or more constraints omitted from trellised block partitioning. In floating block-partitioning the trellising constraint may be omitted and the dimensions of a block may differ from the dimensions of an adjacent block. A maximum block size, other than the frame or tile size, may be expressed as a cardinality of pixels. In some implementations, a maximum block width may be used for blocks unconstrained by a maximum block height. In some implementations, a maximum block height may be used for blocks unconstrained by a maximum block width. Floating block-partitioning may omit using sub-blocks.

For simplicity and clarity, data for a block, other than block dimension data and block location data, such as pixel data, transform coefficients, residual data, motion data, prediction data, transform data, or the like, may be referred to herein as image content for the block. The block dimension data may indicate a height, a width, or both, for a block. For example, the block height may indicate a cardinality of rows of pixels in the block and the block width may indicate a cardinality of columns of pixels in the block. The block location data may express a location of the block in the portion700. For example, the block location data may express the location of the block using coordinates, such as cartesian coordinates, of a portion of the block, such as the top-left pixel of the block as shown, or a center of the block. For example, the block location data may express the location of block in the portion700by indicating a row and column of the portion700corresponding to the top-left pixel of the block.

FIG. 8is a flowchart diagram of an example of coding using lexicographic coding order with floating block-partitioning800in accordance with implementations of this disclosure. Coding using lexicographic coding order, such as raster-lexicographic coding order or contextual-lexicographic coding order, with floating block-partitioning800may be implemented in an encoder, such as the encoder400shown inFIG. 4. Coding using lexicographic coding order with floating block-partitioning800may be implemented in a decoder, such as the decoder500shown inFIG. 5. Although the encoder400shown inFIG. 4and the decoder500shown inFIG. 5are described with respect to video coding, coding using lexicographic coding order with floating block-partitioning800may be implemented for still image coding, video coding, or both. Coding using lexicographic coding order with floating block-partitioning800may be similar to coding using trellised block partitioning, except as described herein or otherwise clear from context. Contextual-lexicographic coding order may be referred to herein as a lexicographic coding order.

An image (frame), or a portion thereof, such as tile, may include pixels, or pixel locations, which may be expressed or identified by spatial location within the image, or tile, which may be expressed using coordinates, such as cartesian coordinates, such that the image, or tile, may be a totally ordered set, wherein the set of pixel locations, as expressed using cartesian coordinates {i,j}, are an alphabet, and the order is a lexicographic order, such that {i1, j1} is less than or equal to {i2, j2} wherein i1 is less than i2 or both i1 is i2 and j1 is less than or equal to j2, and {i1, j1} is otherwise greater than {i2, j2}. Blocks may be referred to by block location, which may correspond with a pixel location in the frame or tile of a top-left pixel, or pixel location, of the block, such that a lexicographic order with respect to blocks may be such that for a first block (B1={y1, x1}) and a second block (B2={y2, x2}), B1<B2=>(y1<y2) or (y1==y2 and x1<x2).

As shown inFIG. 8, coding using lexicographic coding order with floating block-partitioning800includes obtaining image data at810, obtaining block dimensions and location data at820, coding block pixel data at830, and generating a reconstructed frame at840.

Image data may be obtained at810. Obtaining the image data at810may include obtaining image data for a frame, or a portion of a frame, such as the portion700shown inFIG. 7. Encoding using lexicographic coding order with floating block-partitioning may include obtaining an input image at810. The input image may be an uncompressed input, or source, image or video frame. For example, the encoder may receive, or otherwise access, an input image or input video stream or signal, or a portion thereof, and may identify the input image or a portion of the input video stream as the current input image. Identifying an input image may include receiving one or more input images at a buffer and buffering the input images, or one or more respective image portions. Decoding using lexicographic coding order with floating block-partitioning may include obtaining encoded image data at810. Obtaining the encoded image data may include receiving a compressed bitstream, such as the compressed bitstream502shown inFIG. 5, and reading the encoded image data, or a portion thereof, from the compressed bitstream. For example, the decoder, or the decoding path of the encoder, may decode a header for the portion, such as a frame header or a tile header. In some implementations, the decoder, or the decoding path of the encoder, may decode a block header for a block of the portion.

Block dimensions and location data may be obtained at820.

Encoding using lexicographic coding order with floating block-partitioning may include determining block dimensions and location data for respective blocks using rate-distortion optimization. Encoding using lexicographic coding order with floating block-partitioning may include the inclusion of data identifying block dimensions for respective blocks in an encoded output bitstream, such as the compressed bitstream404shown inFIG. 4. In some implementations, the data identifying the block dimensions for the respective blocks may be included in the encoded output bitstream sequentially in lexicographic coding order, such as in a header for a frame, or a portion of a frame, such as the portion700shown inFIG. 7, such as a frame header or a tile header. Pixel data or other block content data, other than the block dimensions and block location data, may be included in the encoded bitstream subsequent to the data identifying the block dimensions, the block location data, or both, as shown at830. In some implementations, the data identifying the block dimensions for the respective blocks may be interleaved with the block content data. For example, the data identifying the block dimensions for a block may be included in a header for the block. In some implementations, the encoder may include the block location data with the data identifying the block dimensions. In some implementations, the encoder may omit the block location data from the encoded bitstream. In some implementations, encoding using lexicographic coding order with floating block-partitioning may include determining block location data for respective blocks.

Decoding using lexicographic coding order with floating block-partitioning may include decoding block dimensions for respective blocks from an encoded bitstream, such as the compressed bitstream502shown inFIG. 5. In some implementations, decoding using lexicographic coding order with floating block-partitioning may include decoding block location data for respective blocks from the encoded bitstream. In some implementations, the encoded bitstream may omit the block location data and decoding using lexicographic coding order with floating block-partitioning may include determining block location data for respective blocks.

Determining block location data for respective blocks may include using available context data, one or more block location constraints, the block dimensions, or a combination thereof. The available context data may indicate previously obtained block location and dimension data (previously identified blocks), which may indicate whether respective pixel locations in the frame, or the portion of the frame, such as the portion700shown inFIG. 7, are available for the current block. Pixel locations that are within previously identified blocks for the frame, or the portion of the frame, such as the portion700shown inFIG. 7, are unavailable.

The block location constraints may include a column constraint and a row constraint. The intersection of a column identified in accordance with the column constraint and a row identified in accordance with the row constraint may indicate the block location, such as a location of a pixel, such as the top-left pixel or the top-right pixel, of the block.

The row constraint may be a minimum available row constraint indicating that the block location includes the minimum, such as nearest to the top of the frame, or the portion of the frame, such as the portion700shown inFIG. 7, row that includes locations, corresponding to pixels or intersections of the row with pixel columns, that are available.

The column constraint may be a minimum available column constraint indicating that the block location includes the minimum, such as nearest to the left of the frame, or the portion of the frame, such as the portion700shown inFIG. 7, column that includes locations, corresponding to pixels or intersections of the column with pixel rows, that are available.

The column constraint may be a context constraint, which may be a column constraint indicating a column adjacent to an identified block, for which block location and dimension data is available, such as previously obtained, in a defined direction, such as to the left of the identified block, such as wherein the decoding the block content of the identified block may include using the block content in the column as context.

The block location constraints may be prioritized. For example, the context constraint, may have a higher priority than the row constraint and the minimum available row constraint may have a higher priority than the minimum available column constraint. Other constraints may be used.

For simplicity and clarity, the block location constraints for a block may be expressed as the set “(row constraint, column constraint)”. For example, the block location constraint “(min, min)” may indicate the minimum row constraint and the minimum column constraint, which may indicate that the top-left pixel of the block is located at the pixel location in the portion700that is in the minimum available row and in the minimum available column within the minimum available row. In another example, a block location constraint “(min, context)” may indicate the context column constraint and the minimum row constraint, which may indicate that the top-right pixel of the block is located at the pixel location in the context column, immediately adjacent to the left of an identified block, and within the minimum available row within the context column.

Image content data for the block may be coded at830. Encoding using lexicographic coding order with floating block-partitioning may include prediction, such as the prediction shown at410inFIG. 4, transformation, such as the transformation shown at420inFIG. 4, quantization, such as the quantization shown at430inFIG. 4, entropy encoding, such as the entropy encoding shown at440inFIG. 4, or a combination thereof. Encoding using lexicographic coding order with floating block-partitioning may include outputting encoded block content data to an encoded bitstream, such as the compressed bitstream404shown inFIG. 4. The encoder may encode a current block from the frame, or the portion of the frame, such as the portion700shown inFIG. 7, subsequent to encoding and reconstructing context blocks from the frame, or the portion of the frame, such as the portion700shown inFIG. 7, for the current block. Encoding using lexicographic coding order with floating block-partitioning may include decoding an encoded block and generating a corresponding reconstructed block, as shown at450-480inFIG. 7, for use as context for encoding other blocks from the frame, or the portion of the frame, such as the portion700shown inFIG. 7.

Decoding using lexicographic coding order with floating block-partitioning may include entropy decoding, such as the entropy decoding shown at510inFIG. 5, dequantization, such as the dequantization shown at520inFIG. 5, inverse transformation, such as the inverse transformation shown at530inFIG. 5, reconstruction, such as the reconstruction550shown inFIG. 5, prediction, such as the prediction shown at540inFIG. 5, filtering, such as the filtering shown at560inFIG. 5, or a combination thereof.

The order of decoding the image content for respective blocks may differ from the lexicographic coding order. For example, the coding order for the image content may include coding the blocks at the corners of the frame or frame portion prior to coding other blocks of the frame or frame portion, or the coding order for the image content may include coding on a per-column basis, or coding order for the image content may include using prediction type information for the respective blocks to determine the coding order. Other coding orders for the image content may be used.

A reconstructed frame, or a portion thereof, such as a reconstructed tile, may be generated at840. Generating the reconstructed frame, or reconstructed frame portion, may include the inclusion of the decoded, or reconstructed, block content obtained at730in the frame in accordance with the block dimensions and the block location data obtained at720.

FIG. 9is a flowchart diagram of an example of coding using contextual-lexicographic coding order with floating block-partitioning900in accordance with implementations of this disclosure. Coding using contextual-lexicographic coding order with floating block-partitioning900may be implemented in an encoder, such as in the decode path of the encoder400shown inFIG. 4, or a decoder, such as the decoder500shown inFIG. 5. Although the encoder400shown inFIG. 4and the decoder500shown inFIG. 5are described with respect to video coding, coding using contextual-lexicographic coding order with floating block-partitioning900may be implemented for still image coding, video coding, or both.

As shown inFIG. 9, coding using contextual-lexicographic coding order with floating block-partitioning900may include determining whether context data is identified as unavailable for decoding a current block at910, decoding the image content for the current block at920, determining whether a stack, such as a pending-block-stack, for tracking blocks for which dimensions are available and at least some context is unavailable includes a block at930, identifying a (min, min) block location constraint at940, obtaining block dimensions at950, identifying block location data at960, pushing the current block on to the stack at970, identifying a (min, context) block location constraint at980, or a combination thereof.

Whether context data is identified as unavailable for decoding a current block may be determined at910. Determining whether context data is identified as unavailable for decoding a current block may be equivalent to determining whether at least some context is unavailable for decoding the image content data for the current block. The context for decoding a block may be spatially oriented in the frame, or frame portion, such as the portion700shown inFIG. 7, in a defined direction relative to the block. For example, the context may include image content above the current block in the portion and image content to the left of the current block in the portion. For blocks along the boundaries of the frame, or frame portion, wherein the frame, or frame portion, omits image content corresponding to the context, such as image content above the portion and image content to the left of the portion, determining whether context data is identified as unavailable for decoding the block may include identifying the absence of unavailable context.

For example, the context for coding the current block may be reconstructed image content above the block and to the left of the block. For a block at the top-left corner of the frame, or frame portion, prior to coding the blocks of the frame, or frame portion, the determination may identify the absence of unavailable context. For a block at the bottom-right corner of the frame, or frame portion, prior to coding the blocks of the frame, or frame portion, the determination may identify unavailable context, which may be equivalent to determining that at least some context is unavailable for decoding the image content data for the current block. Prior to coding the dimensions and location data for at least one block from the frame, or frame portion, determining whether context data is identified as unavailable for decoding a current block at910may be omitted.

The image content of the current block may be coded at920. For example, the image content of the current block may be coded at920in response to identifying at910the absence of unavailable context for coding the image content of the current block. Coding the image content of the current block at920is shown with a broken line boarder to indicate that the block coding order for coding the image content of the current block may differ from the contextual-lexicographic coding order for coding the block location described herein. In some implementations, the image content of a block may be coded in response to identifying the absence of unavailable context for coding the image content block, as shown. In some implementations, the image content of a block may be coded subsequent to coding the block location data for the blocks of the image portion. Coding the image content for the current block may be similar to coding the image content for a block shown at830inFIG. 8, except as described herein or otherwise clear from context. Prior to coding the dimensions and location data for at least one block from the frame, or frame portion, decoding the image content of the current block at920may be omitted.

Whether the stack for tracking blocks for which block dimensions are available and at least some context is unavailable includes a block may be determined at930. The stack may be an ordered data structure, such as a last-in-first-out array. Prior to coding the dimensions and location data for at least one block from the frame, or frame portion, determining whether the stack includes a block at930may be omitted. Determining whether the stack includes a block may include determining whether the stack has a cardinality of zero. The cardinality of the stack may be a count or number of blocks, which may be referred to as stacked blocks, in the stack. A maximum cardinality of the stack may indicate a maximum count or number of blocks that may concurrently be in the stack

Coding using contextual-lexicographic coding order with floating block-partitioning900may include determining that the stack includes a block at930. The block from the stack, such as the block most recently added to the stack, which may be referred to as the most recently pushed block, may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning900may include determining whether the context for coding the image content of the current block is unavailable at910.

A minimum row and minimum column (min, min) block location constraint may be identified at940. For example, the minimum row and minimum column (min, min) block location constraint may be identified at940in response to determining that the stack omits a block, which may correspond with the stack having a cardinality of zero, at930or in response to omitting determining whether the stack includes a block at930.

Block dimensions for the current block may be obtained at950. Obtaining the block dimensions at950may be similar to obtaining block dimensions as shown at820inFIG. 8, except as described herein or otherwise clear from context. For example, encoding the current block may include identifying the block dimensions at950based on rate-distortion optimization and including the block dimensions in an encoded output bitstream. In another example, decoding the current block may include decoding the block dimensions from an encoded bitstream.

Block location data for the current block may be identified at960. Identifying the block location data at960may be similar to identifying block location data for a block as shown at820inFIG. 8, except as described herein or otherwise clear from context. Subsequent to obtaining the block location data for the current block at960, coding using contextual-lexicographic coding order with floating block-partitioning900may include determining whether context data is identified as unavailable for decoding the current block at910.

The current block may be pushed on, or added to, the stack at970. For example, in response to determining that context data is identified as unavailable for decoding the current block at910, the current block may be pushed on the stack at970, and a subsequent, previously unidentified, block may be identified as the current block. The stack, including the most recently pushed block added to the stack at970, may have a cardinality greater than zero (0).

A minimum row and context column (min, context) block location constraint may be identified for the current block at980. For example, the minimum row and context column (min, context) block location constraint may be identified at980in response to pushing a previous block on the stack at970. Subsequent to identifying the minimum row and context column (min, context) block location constraint for the current block at980, block dimensions may be coded for the current block at950and block location data for the current block may be identified at960. In some implementations, the block location data and the block dimensions for the current block may be previously identified and obtaining block dimensions for the current block at950and block location data for the current block at960may be omitted for the current block.

FIGS. 10-17are a series of block diagrams of raster-lexicographic coding order with floating block-partitioning for a frame, or a portion of a frame, such as the frame portion700shown inFIG. 7, in accordance with implementations of this disclosure.FIGS. 18-31are a series of block diagrams of contextual-lexicographic coding order with floating block-partitioning for a frame, or a portion of a frame, such as the frame portion700shown inFIG. 7, in accordance with implementations of this disclosure.

FIG. 10is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1000, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a first block702, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The first block702is shown as a 9×3 block. The first block702is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the first block702are unavailable. The unavailable image content for the block may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the first block702and including the block dimension data for the first block702in the output bitstream. The block location data for the first block702may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the first block702may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the first block702, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the first block702and decoding the portion700may include determining the block location. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown inFIG. 7, prior to obtaining the block location and dimension data for the first block, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is the left column (column0) of the portion700. Decoding the block dimension data for the first block702may include decoding a block height of nine pixels and a block width of three pixels.

As shown at1010, subsequent to obtaining block dimensions and location data for the first block702as shown at1000, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a second block704, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The second block704is shown as a 2×8 block. The second block704is shown with a solid white background to indicate that the image content, such as pixel values, for the second block704are unavailable. The unavailable image content for the block may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the second block704and including the block dimension data for the second block704in the output bitstream. The block location data for the second block704may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the second block704may be included in the output bitstream

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the second block704, such as from the encoded bitstream

In some implementations, the encoded bitstream may omit the block location information for the second block704and decoding the portion700may include determining the block location for the second block704. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1000inFIG. 10, prior to obtaining the block location and dimension data for the second block704, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column3of the portion700. Decoding the block dimension data for the second block704may include decoding a block height of two pixels and a block width of eight pixels.

FIG. 11is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1100, subsequent to obtaining block dimensions and location data for the second block704as shown at1010inFIG. 10, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a third block706, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The third block706is shown as a 16×3 block. The third block706is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the third block706are unavailable. The unavailable image content may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the third block706and including the block dimension data for the third block706in the output bitstream. The block location data for the third block706may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the third block706may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the third block706, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the third block706and decoding the portion700may include determining the block location for the third block706. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1010inFIG. 10, prior to obtaining the block location and dimension data for the third block706, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is the column11of the portion700. Decoding the block dimension data for the third block706may include decoding a block height of 16 pixels and a block width of three pixels.

As shown at1110, subsequent to obtaining block dimensions and location data for the third block706as shown at1100, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fourth block708, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fourth block708is shown as a 7×9 block. The fourth block708is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fourth block708are unavailable. The unavailable image content may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the fourth block708and including the block dimension data for the fourth block708in the output bitstream. The block location data for the fourth block708may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the fourth block708may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the fourth block708, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fourth block708and decoding the portion700may include determining the block location for the fourth block708. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1100inFIG. 11, prior to obtaining the block location and dimension data for the fourth block708, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column14of the portion700. Decoding the block dimension data for the fourth block708may include decoding a block height of seven pixels and a block width of nine pixels.

FIG. 12is a block diagram of raster-lexicographic coding order with floating block-partitioning for the frame portion700, in accordance with implementations of this disclosure. As shown at1200, subsequent to obtaining block dimensions and location data for the fourth block708as shown at1110inFIG. 11, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fifth block710, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fifth block710is shown as a 11×9 block. The fifth block710is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fifth block710are unavailable. The unavailable image content for the block may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the fifth block710and including the block dimension data for the fifth block710in the output bitstream. The block location data for the fifth block710may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the fifth block710may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the fifth block710, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fifth block710and decoding the portion700may include determining the block location for the fifth block710. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1110inFIG. 11, prior to obtaining the block location and dimension data for the fifth block710, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column23of the portion700. Decoding the block dimension data for the fifth block710may include decoding a block height of eleven pixels and a block width of nine pixels.

As shown at1210, subsequent to obtaining block dimensions and location data for the fifth block710as shown at1200, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a sixth block712, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The sixth block712is shown as a 9×3 block. The sixth block712is shown with a solid white background to indicate that the reconstructed image content, such as pixel values, for the sixth block712are unavailable. The unavailable image content for the sixth block712may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the sixth block712.

Encoding the portion700may include identifying the block location and dimension data for the sixth block712and including the block dimension data for the sixth block712in the output bitstream. The block location data for the sixth block712may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the sixth block712may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the sixth block712, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the sixth block712and decoding the portion700may include determining the block location for the sixth block712. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1200inFIG. 12, prior to obtaining the block location and dimension data for the sixth block712, the minimum available row is row2of the portion700and the minimum available column within the minimum available row is column3of the portion700. Decoding the block dimension data for the sixth block712may include decoding a block height of nine pixels and a block width of three pixels.

FIG. 13is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1300, subsequent to obtaining block dimensions and location data for the sixth block712as shown at1210inFIG. 12, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a seventh block714, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The seventh block714is shown as a 5×5 block. The seventh block714is shown with a solid white background to indicate that the content, such as pixel values, for the seventh block714are unavailable. The unavailable image content for the block may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the seventh block714and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the seventh block714from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the seventh block714and decoding the portion700may include determining the block location for the seventh block714. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1210inFIG. 12, prior to obtaining the block location and dimension data for the seventh block714, the minimum available row is row2of the portion700and the minimum available column within the minimum available row is column6of the portion700. Decoding the block dimension data for the seventh block714may include decoding a block height of five pixels and a block width of five pixels.

As shown at1310, subsequent to obtaining block dimensions and location data for the seventh block714as shown at1300, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for an eighth block716, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The eighth block716is shown as a 9×5 block. The eighth block716is shown with a solid white background to indicate that the content, such as pixel values, for the eighth block716are unavailable. The unavailable image content for the block may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the eighth block716and including the block dimension data or the block dimension data and the block location data for the eighth block716in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the eighth block716from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the eighth block716and decoding the portion700may include determining the block location for the eighth block716. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1300inFIG. 13, prior to obtaining the block location and dimension data for the eighth block716, the minimum available row is row7of the portion700and the minimum available column within the minimum available row is column6of the portion700. Decoding the block dimension data for the eighth block716may include decoding a block height of nine pixels and a block width of five pixels.

FIG. 14is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1400, subsequent to obtaining block dimensions and location data for the eighth block716as shown at1310inFIG. 13, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a ninth block718, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The ninth block718is shown as a 5×4 block. The ninth block718is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the ninth block718are unavailable. The unavailable image content may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the ninth block718and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the ninth block718from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the ninth block718and decoding the portion700may include determining the block location for the ninth block718. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1310inFIG. 13, prior to obtaining the block location and dimension data for the ninth block718, the minimum available row is row7of the portion700and the minimum available column within the minimum available row is column14of the portion700. Decoding the block dimension data for the ninth block718may include decoding a block height of five pixels and a block width of four pixels.

As shown at1410, subsequent to obtaining block dimensions and location data for the ninth block718as shown at1400, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for an tenth block720, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The tenth block720is shown as a 5×5 block. The tenth block720is shown with a solid white background to indicate that the content, such as pixel values, for the tenth block720are unavailable. The unavailable image content may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the tenth block720and including the block dimension data or the block dimension data and the block location data for the tenth block720in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the tenth block720from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the tenth block720and decoding the portion700may include determining the block location for the tenth block720. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1400inFIG. 14, prior to obtaining the block location and dimension data for the tenth block720, the minimum available row is row7of the portion700and the minimum available column within the minimum available row is column18of the portion700. Decoding the block dimension data for the tenth block720may include decoding a block height of five pixels and a block width of five pixels.

FIG. 15is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1500, subsequent to obtaining block dimensions and location data for the tenth block720as shown at1410inFIG. 14, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for an eleventh block722, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The eleventh block722is shown as a 7×3 block. The eleventh block722is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the eleventh block722are unavailable. The unavailable image content may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the eleventh block722and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the eleventh block722from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the eleventh block722and decoding the portion700may include determining the block location for the eleventh block722. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1410inFIG. 14, prior to obtaining the block location and dimension data for the eleventh block722, the minimum available row is row9of the portion700and the minimum available column within the minimum available row is column0of the portion700. Decoding the block dimension data for the eleventh block722may include decoding a block height of seven pixels and a block width of three pixels.

As shown at1510, subsequent to obtaining block dimensions and location data for the eleventh block722as shown at1500, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a twelfth block724, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The twelfth block724is shown as a 5×3 block. The twelfth block724is shown with a solid white background to indicate that the content, such as pixel values, for the twelfth block724are unavailable. The unavailable image content may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the twelfth block724and including the block dimension data or the block dimension data and the block location data for the twelfth block724in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the twelfth block724from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the twelfth block724and decoding the portion700may include determining the block location for the twelfth block724. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1500inFIG. 15, prior to obtaining the block location and dimension data for the twelfth block724, the minimum available row is row11of the portion700and the minimum available column within the minimum available row is column3of the portion700. Decoding the block dimension data for the twelfth block724may include decoding a block height of five pixels and a block width of three pixels.

FIG. 16is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1600, subsequent to obtaining block dimensions and location data for the twelfth block724as shown at1510inFIG. 15, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a thirteenth block726, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The thirteenth block726is shown as a 5×4 block. The thirteenth block726is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the thirteenth block726are unavailable. The unavailable image content may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the thirteenth block726and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the thirteenth block726from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the thirteenth block726and decoding the portion700may include determining the block location for the thirteenth block726. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1510inFIG. 15, prior to obtaining the block location and dimension data for the thirteenth block726, the minimum available row is row11of the portion700and the minimum available column within the minimum available row is column23of the portion700. Decoding the block dimension data for the thirteenth block726may include decoding a block height of five pixels and a block width of four pixels.

As shown at1610, subsequent to obtaining block dimensions and location data for the thirteenth block726as shown at1600, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fourteenth block728, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fourteenth block728is shown as a 5×5 block. The fourteenth block728is shown with a solid white background to indicate that the content, such as pixel values, for the fourteenth block728are unavailable. The unavailable image content may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the fourteenth block728and including the block dimension data or the block dimension data and the block location data for the fourteenth block728in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fourteenth block728from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fourteenth block728and decoding the portion700may include determining the block location for the fourteenth block728. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1600inFIG. 16, prior to obtaining the block location and dimension data for the fourteenth block728, the minimum available row is row11of the portion700and the minimum available column within the minimum available row is column27of the portion700. Decoding the block dimension data for the fourteenth block728may include decoding a block height of five pixels and a block width of five pixels.

FIG. 17is a block diagram of raster-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1700, subsequent to obtaining block dimensions and location data for the fourteenth block728as shown at1610inFIG. 16, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fifteenth block730, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fifteenth block730is shown as a 4×5 block. The fifteenth block730is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fifteenth block730are unavailable. The unavailable image content may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the fifteenth block730and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fifteenth block730from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fifteenth block730and decoding the portion700may include determining the block location for the fifteenth block730. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1610inFIG. 16, prior to obtaining the block location and dimension data for the fifteenth block730, the minimum available row is row12of the portion700and the minimum available column within the minimum available row is column14of the portion700. Decoding the block dimension data for the fifteenth block730may include decoding a block height of four pixels and a block width of five pixels.

As shown at1710, subsequent to obtaining block dimensions and location data for the fifteenth block730as shown at1700, raster-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a sixteenth block732, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The sixteenth block732is shown as a 4×4 block. The sixteenth block732is shown with a solid white background to indicate that the content, such as pixel values, for the sixteenth block732are unavailable. The unavailable image content may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the sixteenth block732and including the block dimension data or the block dimension data and the block location data for the sixteenth block732in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the sixteenth block732from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the sixteenth block732and decoding the portion700may include determining the block location for the sixteenth block732. Raster-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min). As shown at1700inFIG. 17, prior to obtaining the block location and dimension data for the sixteenth block732, the minimum available row is row12of the portion700and the minimum available column within the minimum available row is column19of the portion700. Decoding the block dimension data for the sixteenth block732may include decoding a block height of four pixels and a block width of four pixels.

FIG. 18is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at1800, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a first block750, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The first block750is shown as a 9×3 block. The first block750is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the first block750are unavailable. The unavailable reconstructed image content for the first block750may be obtained, such as decoded at a decoder or the decoding path of an encoder, subsequent to obtaining the block dimension and location data for the first block750.

Encoding the portion700may include identifying the block location and dimension data for the first block750and including the block dimension data for the first block750in the output bitstream. The block location data for the first block750may be omitted from the output bitstream. In some implementations, the block dimension data and the block location data for the first block750may be included in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data, the block dimension data, or both for the first block750, such as from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the first block750and decoding the portion700may include determining the block location for the first block750. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the first block750may include decoding a block height of nine pixels and a block width of three pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the first block750, the available location context may be the boundaries, such as the top and left boundaries, of the portion700. As shown inFIG. 7, prior to obtaining the block location and dimension data for the first block, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is the left column (column0) of the portion700.

As shown at1810, subsequent to obtaining block dimensions and location data for the first block750as shown at1800, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the content of the first block750is unavailable, as shown at910inFIG. 9. The context for decoding the first block750may be the boundaries of the portion700, which may be identified as available. The image content, such as pixel values, for the first block750may be decoded and reconstructed, as shown at920inFIG. 9. The first block750is shown inFIG. 18with a stippled background to indicate that, subsequent to obtaining block dimensions and location data for the first block750as shown at1800, the reconstructed image content for the first block750may be identified as available for coding a subsequently coded block, which may indicate an expectation of availability. The image content for the first block750may be decoded subsequent to obtaining block dimensions and location data for the first block750as shown at1800, which may be prior to obtaining block dimensions and location data for the second block752as shown at1810, concurrent with obtaining block dimensions and location data for the second block752as shown at1810, or subsequent to obtaining block dimensions and location data for the second block752as shown at1810. The image content for the first block750may be decoded prior to decoding the image content for the second block752.

As shown at1810, subsequent to identifying reconstructed image content for the first block750as available, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a second block752, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The second block752is shown as a 2×8 block. The second block752is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the second block752are unavailable. The unavailable image content may be obtained, such as decoded at a decoder and reconstructed, subsequent to obtaining the block dimension and location data.

Encoding the portion700may include identifying the block location and dimension data for the second block752and including the block dimension data or the block dimension data and the block location data for the second block752in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the second block752from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the second block752and decoding the portion700may include determining the block location for the second block752. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the second block752may include decoding a block height of two pixels and a block width of eight pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the second block752, the available location context may be the top boundary of the portion700and the first block750. As shown at1800inFIG. 18, prior to obtaining the block location and dimension data for the second block752, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column3of the portion700.

FIG. 19is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at1900, subsequent to obtaining block dimensions and location data for the second block752as shown at1810inFIG. 18, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the content of the second block752is unavailable, as shown at910inFIG. 9. The context for decoding the second block752may include the top boundary of the portion700, which may be identified as available, and the reconstructed image content of the first block750, which may be identified as available, which may indicate an expectation of availability. The second block752is shown inFIG. 19with a stippled background to indicate that, subsequent to obtaining block dimensions and location data for the second block752as shown at1810inFIG. 18, the image content for the second block752may be identified as available for coding a subsequently coded block. The image content for the second block752may be decoded, as indicated at920inFIG. 9, subsequent to obtaining block dimensions and location data for the second block752, which may be prior to obtaining block dimensions and location data for the third block754as shown at1900, concurrent with obtaining block dimensions and location data for the third block754, or subsequent to obtaining block dimensions and location data for third block754. The image content for the second block752may be decoded prior to decoding the image content for the third block754.

As shown at1900, subsequent to identifying image content for the second block752as available, as shown at1810inFIG. 18, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a third block754, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The third block754is shown as a 16×3 block. The third block754is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the third block754are unavailable. The unavailable image content for the third block754may be obtained, such as decoded and reconstructed at a decoder, subsequent to obtaining the block dimension and location data for the third block754.

Encoding the portion700may include identifying the block location and dimension data for the third block754and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the third block754from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the third block754and decoding the portion700may include determining the block location for the third block754. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the third block754may include decoding a block height of sixteen pixels and a block width of three pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the third block754, the available location context may be the top boundary of the portion700and the second block752. As shown at1810inFIG. 18, prior to obtaining the block location and dimension data for the third block754, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column11of the portion700.

As shown at1910, subsequent to obtaining block dimensions and location data for the third block754as shown at1900, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the third block754is unavailable, as shown at910inFIG. 9. The context for decoding the third block754may include the top boundary of the portion700, which may be identified as available. The context for decoding the third block754may include the reconstructed image content of the second block752, which may be identified as available, which may indicate an expectation of availability. The context for decoding the third block754may include unavailable context adjacent to the third block754in a defined direction, such as to the left of the third block754. In response to determining that at least some context for decoding the third block754is unavailable, an indicator or identifier for the third block754may be pushed or added to a stack1920(pending-block-stack), or other last-in-first-out ordered data structure, for tracking blocks for which dimensions are available and at least some context is unavailable, as shown at970inFIG. 9. Other data structures, or combinations thereof, may be used for tracking blocks for which dimensions are available and at least some context is unavailable. Prior to pushing the third block954on the stack1920as shown at970inFIG. 9, the stack1920may have a cardinality of zero. Subsequent to pushing the third block954on the stack1920as shown at970inFIG. 9, the stack1920may have a cardinality greater than zero, such as one.

As shown at1910, subsequent to pushing the third block954on the stack1920as shown at970inFIG. 9, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fourth block756, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fourth block756is shown as a 5×5 block. The fourth block756is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fourth block756are unavailable. The unavailable image content for the fourth block756may be obtained, such as decoded and reconstructed at a decoder, subsequent to obtaining the block dimension and location data for the fourth block756and subsequent to obtaining the image content of the context for decoding the fourth block756.

Encoding the portion700may include identifying the block location and dimension data for the fourth block756and including the block dimension data or the block dimension data and the block location data for the fourth block756in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fourth block756from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fourth block756and decoding the portion700may include determining the block location for the fourth block756. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the fourth block756may include decoding a block height of five pixels and a block width of five pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the fourth block756, the available location context may be the second block752and the third block754. As shown at1900inFIG. 19, prior to obtaining the block location and dimension data for the fourth block756, the minimum available row is row3, corresponding to one row greater than the maximum row of the second block752, of the portion700and the maximum available column within the minimum available row is column10of the portion700, corresponding to one column less than the minimum column of the third block754.

FIG. 20is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2000, subsequent to obtaining block dimensions and location data for the fourth block756as shown at1910inFIG. 19, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fourth block756is unavailable, as shown at910inFIG. 9. The context for decoding the fourth block756may include the reconstructed image content of the second block752, which may be identified as available. The context for decoding the fourth block756may include unavailable context adjacent to the fourth block756in a defined direction, such as to the left of the fourth block756. The fourth block756is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fourth block756are unavailable. In response to determining that at least some context for decoding the fourth block756is unavailable, an indicator or identifier for the fourth block756may be pushed or added to the stack1920, as shown at970inFIG. 9. Subsequent to pushing the fourth block756on the stack1920as shown at970inFIG. 9, the stack1920may have a cardinality greater than zero, such as two.

As shown at2000, subsequent to pushing the fourth block756on the stack1920as shown at970inFIG. 9, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fifth block758, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fifth block758is shown as a 9×3 block. The fifth block758is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fifth block758are unavailable. Unavailable image content for the fifth block758may be obtained, such as decoded and reconstructed at a decoder, subsequent to obtaining the block dimension and location data for the fifth block758and subsequent to obtaining the image content of the context for decoding the fifth block758.

Encoding the portion700may include identifying the block location and dimension data for the fifth block758and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fifth block758from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fifth block758and decoding the portion700may include determining the block location for the fifth block758. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the fifth block758may include decoding a block height of nine pixels and a block width of three pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the fifth block758, the available location context may be the second block752and the fourth block756. As shown at1910inFIG. 19, prior to obtaining the block location and dimension data for the fifth block758, the minimum available row is row three of the portion700, corresponding to one row greater than the maximum row of the second block752, and the maximum available column within the minimum available row is column five of the portion700, corresponding to one column less than the minimum column of the fourth block756.

As shown at2010, subsequent to obtaining block dimensions and location data for the fifth block758as shown at2000, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fifth block758is unavailable, as shown at910inFIG. 9. The context for decoding the fifth block758may include the reconstructed image content of the first block750, which may be identified as available. The context for decoding the fifth block758may include the reconstructed image content of the second block752, which may be identified as available. The context for decoding the fifth block758may include unavailable context adjacent to the fifth block758in a defined direction, such as to the left of the fifth block758. In response to determining that at least some context for decoding the fifth block758is unavailable, an indicator or identifier for the fifth block758may be pushed or added to the stack1920, as shown at970inFIG. 9. Subsequent to pushing the fifth block758on the stack1920as shown at970inFIG. 9, the stack1920may have a cardinality greater than zero, such as three.

As shown at2010, subsequent to pushing the fifth block758on the stack1920as shown at970inFIG. 9, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a sixth block760, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The sixth block760is shown as a 7×3 block. The sixth block760is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the sixth block760are unavailable. The unavailable image content for the sixth block760may be obtained, such as decoded and reconstructed at a decoder, subsequent to obtaining the block dimension and location data for the sixth block760and subsequent to obtaining the image content of the context for decoding the sixth block760.

Encoding the portion700may include identifying the block location and dimension data for the sixth block760and including the block dimension data or the block dimension data and the block location data for the sixth block760in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the sixth block760from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the sixth block760and decoding the portion700may include determining the block location for the sixth block760. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the sixth block760may include decoding a block height of seven pixels and a block width of three pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the sixth block760, the available location context may be the first block750and the fifth block758. As shown at2000inFIG. 20, prior to obtaining the block location and dimension data for the sixth block760, the minimum available row is row nine, corresponding to one row greater than the maximum row of the first block750, of the portion700and the maximum available column within the minimum available row is column three of the portion700, corresponding to one column less than the minimum column of the fifth block758.

FIG. 21is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure. As shown at2100, subsequent to obtaining block dimensions and location data for the sixth block760as shown at2010inFIG. 20, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the content of the sixth block760is unavailable, as shown at910inFIG. 9. The context for decoding the sixth block760may include the reconstructed image content of the first block750and the left boundary of the portion700, which may be identified as available. The sixth block760is shown inFIG. 21with a stippled background to indicate that, subsequent to obtaining block dimensions and location data for the sixth block760as shown at2010inFIG. 20, the image content for the sixth block760may be identified as available for coding a subsequently coded block. The image content for the sixth block760may be decoded, as indicated at920inFIG. 9, subsequent to obtaining block dimensions and location data for the sixth block760, which may be prior to, concurrent with, or subsequent o obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the sixth block760may be decoded prior to decoding the image content for the fifth block758.

Subsequent to identifying image content for the sixth block760available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack may include the third block754, the fourth block756, and the fifth block758. The stack1920may have a cardinality greater than zero, such as three. As shown at2110, the fifth block758may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fifth block758is unavailable, as shown at910inFIG. 9. The context for decoding the fifth block758may include the reconstructed image content of the first block750, the second block752, and the sixth block760, which may be identified as available. The fifth block758is shown at2110inFIG. 21with a stippled background to indicate that the image content for the fifth block758may be identified as available for coding a subsequently coded block. The image content for the fifth block758may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent o obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the fifth block758may be decoded prior to decoding the image content for the fourth block756. Subsequent to popping the fifth block758from the stack1920, the stack1920may have a cardinality greater than zero, such as two.

FIG. 22is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

Subsequent to identifying the image content for the fifth block758as available, as shown at2110inFIG. 21, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack1920may include the third block754and the fourth block756. The stack1920may have a cardinality of two. As shown at2200, the fourth block756may be identified as the current block, popped or removed from the stack1920, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fourth block756is unavailable, as shown at910inFIG. 9. The context for decoding the fourth block756may include the reconstructed image content of the second block752and the fifth block758, which may be identified as available. The fourth block756is shown at2200inFIG. 22with a stippled background to indicate that the image content for the fourth block756may be identified as available for coding a subsequently coded block. The image content for the fourth block756may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the fourth block756may be decoded prior to decoding the image content for the third block754. Subsequent to popping the fourth block756from the stack1920, the stack1920may have a cardinality greater than zero, such as one.

Subsequent to identifying the image content for the fourth block756as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack1920may include the third block754. The stack1920may have a cardinality of one. As shown at2200, the third block754may be identified as the current block, popped or removed from the stack1920, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the content of the third block754is unavailable, as shown at910inFIG. 9. The context for decoding the third block754may include the reconstructed image content of the second block752and the reconstructed image content of the fourth block756, which may be identified as available. The context for decoding the third block754may include unavailable context adjacent to the third block754in a defined direction, such as to the left of the third block754. In response to determining that at least some context for decoding the third block754is unavailable, the indicator or identifier for the third block754may be pushed or added to the stack1920, as shown at970inFIG. 9. In some implementations, determining whether the context for decoding the content of a block is unavailable may be performed prior to removing the block from the stack and removing the block from the stack may be omitted in response to determining that the context for decoding the content of the block is unavailable.

As shown at2200, subsequent to pushing the third block754on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a seventh block762, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The seventh block762is shown as a 9×5 block. The seventh block762is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the seventh block762are unavailable. The unavailable image content for the seventh block762may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the seventh block762and subsequent to obtaining the image content of the context for decoding the seventh block762.

Encoding the portion700may include identifying the block location and dimension data for the seventh block762and including the block dimension data or the block dimension data and the block location data for the seventh block762in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the seventh block762from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the seventh block762and decoding the portion700may include determining the block location for the seventh block762. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the seventh block762may include decoding a block height of nine pixels and a block width of five pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the seventh block762, the available location context may be the third block754and the fourth block756. As shown at2010inFIG. 20, prior to obtaining the block location and dimension data for the seventh block762, the minimum available row is row7, corresponding to one row greater than the maximum row of the fourth block756, and the maximum available column within the minimum available row is column10, corresponding to one column less than the minimum column of the third block754.

As shown at2210, subsequent to obtaining block dimensions and location data for the seventh block762as shown at2200, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the seventh block762is unavailable, as shown at910inFIG. 9. The context for decoding the seventh block762may include the reconstructed image content of the fourth block756and the reconstructed image content of the fifth block758, which may be identified as available. The context for decoding the seventh block762may include unavailable context adjacent to the seventh block762in a defined direction, such as to the left of the seventh block762. In response to determining that at least some context for decoding the seventh block762is unavailable, an indicator or identifier for the seventh block762may be pushed or added to the stack1920, as shown at970inFIG. 9.

As shown at2210, subsequent to pushing the seventh block762on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for an eighth block764, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The eighth block764is shown as a 5×3 block. The eighth block764is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the eighth block764are unavailable. The unavailable image content for the eighth block764may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the eighth block764and subsequent to obtaining the image content of the context for decoding the eighth block764.

Encoding the portion700may include identifying the block location and dimension data for the eighth block764and including the block dimension data or the block dimension data and the block location data for the eighth block764in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the eighth block764from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the eighth block764and decoding the portion700may include determining the block location for the eighth block764. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the eighth block764may include decoding a block height of five pixels and a block width of three pixels. Identifying the block location may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the eighth block764, the available location context may be the fifth block758and the seventh block762. As shown at2200, prior to obtaining the block location and dimension data for the eighth block764, the minimum available row is row11, corresponding to one row greater than the maximum row of the fifth block758, and the maximum available column within the minimum available row is column5of the portion700, corresponding to one column less than the minimum column of the seventh block762.

FIG. 23is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2300, subsequent to obtaining block dimensions and location data for the eighth block764as shown at2210inFIG. 22, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the eighth block764is unavailable, as shown at910inFIG. 9. The context for decoding the eighth block764may include the reconstructed image content of the fifth block758and the reconstructed image content of the sixth block760, which may be identified as available. The eighth block764is shown at2300inFIG. 23with a stippled background to indicate that the image content for the eighth block764may be identified as available for coding a subsequently coded block. The image content for the eighth block764may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent o obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the eighth block764may be decoded prior to decoding the image content for the seventh block762.

Subsequent to identifying image content for the eighth block764as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack may include the third block754and the seventh block762. As shown at2310, the seventh block762may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the seventh block762is unavailable, as shown at910inFIG. 9. The context for decoding the seventh block762may the reconstructed image content of the fourth block756, the reconstructed image content of the fifth block758, and the reconstructed image content of the eighth block764, which may be identified as available. The seventh block762is shown at2310inFIG. 23with a stippled background to indicate that the image content for the seventh block762may be identified as available for coding a subsequently coded block. The image content for the seventh block762may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the seventh block762may be decoded prior to decoding the image content for the third block754.

FIG. 24is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

Subsequent to identifying the image content for the seventh block762as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack may include the third block754. As shown at2400, the third block754may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the third block754is unavailable, as shown at910inFIG. 9. The context for decoding the third block754may include the reconstructed image content of the second block752, the reconstructed image content of the fourth block756, and the reconstructed image content of the seventh block762, which may be identified as available. The third block754is shown inFIG. 24with a stippled background to indicate that the image content for the third block754may be identified as available for coding a subsequently coded block. The image content for the third block754may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the third block754may be decoded prior to decoding the image content for subsequent blocks from the portion700for which the third block754is context for decoding.

As shown at2400, subsequent to identifying the image content for the third block754as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack1920may omit blocks. Subsequent to determining that the stack1920omits blocks, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a ninth block766, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The ninth block766is shown as a 7×9 block. The ninth block766is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the ninth block766are unavailable. Unavailable image content for the ninth block766may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the ninth block766.

Encoding the portion700may include identifying the block location and dimension data for the ninth block766and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the ninth block766from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the ninth block766and decoding the portion700may include determining the block location. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the ninth block766may include decoding a block height of seven pixels and a block width of nine pixels. Identifying the block location may include using the available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the ninth block766, the available location context may be the top boundary of the portion700and the third block754. As shown at2210inFIG. 22, prior to obtaining the block location and dimension data for ninth block766, the minimum available row is the top row (row0) of the portion700and the minimum available column within the minimum available row is column14of the portion700.

As shown at2410, subsequent to obtaining the block dimensions and location data for the ninth block766as shown at2400, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the ninth block766is unavailable, as shown at910inFIG. 9. The context for decoding the ninth block766may include the top boundary of the portion700and the reconstructed image content of the third block754, which may be identified as available. The ninth block766is shown at2410inFIG. 24with a stippled background to indicate that the image content for the ninth block766may be identified as available for coding a subsequently coded block. The image content for the ninth block766may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the ninth block766may be decoded prior to decoding the image content for subsequent blocks from the portion700for which the ninth block766is context for decoding.

As shown at2410, subsequent to identifying the image content for the ninth block766as available, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a tenth block768, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The tenth block768is shown as an 11×9 block. The tenth block768is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the tenth block768is unavailable. The unavailable image content for the tenth block768may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the tenth block768and subsequent to obtaining the image content of the context for decoding the tenth block768.

Encoding the portion700may include identifying the block location and dimension data for the tenth block768and including the block dimension data or the block dimension data and the block location data for the tenth block768in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the tenth block768from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the tenth block768and decoding the portion700may include determining the block location for the tenth block768. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the tenth block768may include decoding a block height of eleven pixels and a block width of nine pixels. Identifying the block location may include using the available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the tenth block768, the available location context may be the ninth block766and the top boundary of the portion700. As shown at2400, prior to obtaining the block location and dimension data for the tenth block768, the minimum available row is row0of the portion700and the minimum available column within the minimum available row is column23of the portion700.

FIG. 25is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2500, subsequent to obtaining block dimensions and location data for the tenth block768as shown at2410inFIG. 24, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the tenth block768is unavailable, as shown at910inFIG. 9. The context for decoding the tenth block768may include the reconstructed image content of the ninth block766and the top boundary of the portion700, which may be identified as available. The context for decoding the tenth block768may include unavailable context adjacent to the tenth block768in a defined direction, such as to the left of the tenth block768. The tenth block768is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the tenth block768are unavailable. In response to determining that at least some context for decoding the tenth block768is unavailable, an indicator or identifier for the tenth block768may be pushed or added to the stack1920, as shown at970inFIG. 9.

As shown at2500, subsequent to pushing the tenth block768on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for an eleventh block770, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The eleventh block770is shown as a 5×5 block. The eleventh block770is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the eleventh block770is unavailable. The unavailable image content for the eleventh block770may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the eleventh block770and subsequent to obtaining the image content of the context for decoding the eleventh block770.

Encoding the portion700may include identifying the block location and dimension data for the eleventh block770and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the eleventh block770from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the eleventh block770and decoding the portion700may include determining the block location for the eleventh block770. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the eleventh block770may include decoding a block height of five pixels and a block width of five pixels. Identifying the block location may include using the available context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the eleventh block770, the available context may be the ninth block766and the tenth block768. As shown at2410inFIG. 24, prior to obtaining the block location and dimension data for the eleventh block770, the minimum available row is row7, corresponding to one row greater than the maximum row of the ninth block766, and the maximum available column within the minimum available row is column22, corresponding to one column less than the minimum column of the tenth block768.

As shown at2510, subsequent to obtaining block dimensions and location data for the eleventh block770as shown at2500, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the eleventh block770is unavailable, as shown at910inFIG. 9. The context for decoding the eleventh block770may include the reconstructed image content of the ninth block766, which may be identified as available. The context for decoding the eleventh block770may include unavailable context adjacent to the eleventh block770in a defined direction, such as to the left of the eleventh block770. In response to determining that at least some context for decoding the eleventh block770is unavailable, an indicator or identifier for the eleventh block770may be pushed or added to the stack1920, as shown at970inFIG. 9.

As shown at2510, subsequent to pushing the eleventh block770on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a twelfth block772, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The twelfth block772is shown as a 5×4 block. The twelfth block772is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the twelfth block772are unavailable. The unavailable image content for the twelfth block772may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the twelfth block772and subsequent to obtaining the image content of the context for decoding the twelfth block772.

Encoding the portion700may include identifying the block location and dimension data for the twelfth block772and including the block dimension data or the block dimension data and the block location data for the twelfth block772in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the twelfth block772from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the twelfth block772and decoding the portion700may include determining the block location for the twelfth block772. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the twelfth block772may include decoding a block height of five pixels and a block width of four pixels. Identifying the block location may include using the available context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the twelfth block772, the available context may be the ninth block766and the eleventh block770. As shown at2500, prior to obtaining the block location and dimension data for the twelfth block772, the minimum available row is row7, corresponding to one row greater than the maximum row of the ninth block766, and the maximum available column within the minimum available row is column17, corresponding to one column less than the minimum column of the eleventh block770.

FIG. 26is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2600, subsequent to obtaining the block dimensions and location data for the twelfth block772as shown at2510inFIG. 25, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the twelfth block772is unavailable, as shown at910inFIG. 9. The context for decoding the twelfth block772may include the reconstructed image content of the third block754and the reconstructed image content of the ninth block766, which may be identified as available. The twelfth block772is shown at2600inFIG. 26with a stippled background to indicate that the image content for the twelfth block772may be identified as available for coding a subsequently coded block. The image content for the twelfth block772may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the twelfth block772may be decoded prior to decoding the image content for the eleventh block770.

Subsequent to identifying image content for the twelfth block772as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack may include the tenth block768and the eleventh block770. As shown at2610, the eleventh block770may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the eleventh block770is unavailable, as shown at910inFIG. 9. The context for decoding the eleventh block770may the reconstructed image content of the ninth block766and the reconstructed image content of the twelfth block772, which may be identified as available. The eleventh block770is shown at2610inFIG. 26with a stippled background to indicate that the image content for the eleventh block770may be identified as available for coding a subsequently coded block. The image content for the eleventh block770may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent o obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the eleventh block770may be decoded prior to decoding the image content for the tenth block768.

FIG. 27is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

Subsequent to identifying image content for the eleventh block770as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack may include the tenth block768. As shown at2700, the tenth block768may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the tenth block768is unavailable, as shown at910inFIG. 9. The context for decoding the tenth block768may be the reconstructed image content of the ninth block766and the reconstructed image content of the eleventh block770, which may be identified as available. The tenth block768is shown at2700with a stippled background to indicate that the image content for the tenth block768may be identified as available for coding a subsequently coded block. The image content for the tenth block768may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent o obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the tenth block768may be decoded prior to decoding subsequent blocks from the portion700.

As shown at2710, subsequent to identifying image content for the tenth block768as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes any blocks, as shown at930inFIG. 9. The stack1920may omit blocks. Subsequent to determining that the stack1920omits blocks, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a thirteenth block774, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The thirteenth block774is shown as a 5×4 block. The thirteenth block774is shown with a solid white background to indicate that the content, such as pixel values, for the thirteenth block774are unavailable. The unavailable image content for the thirteenth block774may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the thirteenth block774.

Encoding the portion700may include identifying the block location and dimension data for the thirteenth block774and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the thirteenth block774from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the thirteenth block774and decoding the portion700may include determining the block location. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the thirteenth block774may include decoding a block height of five pixels and a block width of four pixels. Identifying the block location may include using the available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the thirteenth block774, the available location context may be the tenth block768and the eleventh block770. As shown at2510inFIG. 25, prior to obtaining the block location and dimension data for thirteenth block774, the minimum available row is row11of the portion700and the minimum available column within the minimum available row is column24of the portion700.

FIG. 28is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2800, subsequent to obtaining block dimensions and location data for the thirteenth block774as shown at2410inFIG. 24, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the thirteenth block774is unavailable, as shown at910inFIG. 9. The context for decoding the thirteenth block774may include the reconstructed image content of the tenth block768and the reconstructed image content of the eleventh block770, which may be identified as available. The context for decoding the thirteenth block774may include unavailable context adjacent to the thirteenth block774in a defined direction, such as to the left of the thirteenth block774. The thirteenth block774is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the thirteenth block774are unavailable. In response to determining that at least some context for decoding the thirteenth block774is unavailable, an indicator or identifier for the thirteenth block774may be pushed or added to the stack1920, as shown at970inFIG. 9.

As shown at2800, subsequent to pushing the thirteenth block774on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fourteenth block776, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fourteenth block776is shown as a 4×4 block. The fourteenth block776is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fourteenth block776are unavailable. The unavailable image content for the fourteenth block776may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the fourteenth block776and subsequent to obtaining the image content of the context for decoding the fourteenth block776.

Encoding the portion700may include identifying the block location and dimension data for the fourteenth block776and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fourteenth block776from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fourteenth block776and decoding the portion700may include determining the block location for the fourteenth block776. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the fourteenth block776may include decoding a block height of four pixels and a block width of four pixels. Identifying the block location may include using the available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the fourteenth block776, the available location context may be the eleventh block770and the thirteenth block774. As shown at2710inFIG. 27, prior to obtaining the block location and dimension data for the fourteenth block776, the minimum available row is row12, corresponding to one row greater than the maximum row of the eleventh block770, and the maximum available column within the minimum available row is column22, corresponding to one column less than the minimum column of the thirteenth block774.

As shown at2810, subsequent to obtaining block dimensions and location data for the fourteenth block776as shown at2800, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fourteenth block776is unavailable, as shown at910inFIG. 9. The context for decoding the fourteenth block776may include the reconstructed image content of the eleventh block770, which may be identified as available. The context for decoding the fourteenth block776may include unavailable context adjacent to the fourteenth block776in a defined direction, such as to the left of the fourteenth block776. In response to determining that at least some of the context for decoding the fourteenth block776is unavailable, an indicator or identifier for the fourteenth block776may be pushed or added to the stack1920, as shown at970inFIG. 9.

Subsequent to pushing the fourteenth block776on the stack1920, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a fifteenth block778, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The fifteenth block778is shown as a 4×5 block. The fifteenth block778is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the fifteenth block778is unavailable. The unavailable image content for the fifteenth block778may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the fifteenth block778and subsequent to obtaining the image content of the context for decoding the fifteenth block778.

Encoding the portion700may include identifying the block location and dimension data for the fifteenth block778and including the block dimension data or the block dimension data and the block location data for the fifteenth block778in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the fifteenth block778from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the fifteenth block778and decoding the portion700may include determining the block location for the fifteenth block778. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the context column constraint, (min, context), as shown at980inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the fifteenth block778may include decoding a block height of four pixels and a block width of five pixels. Identifying the block location for the fifteenth block778may include using available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For the fifteenth block778, the available location context may be the twelfth block772and the fourteenth block776. As shown at2800, prior to obtaining the block location and dimension data for the fifteenth block778, the minimum available row is row12, corresponding to one row greater than the maximum row of the twelfth block772, and the maximum available column within the minimum available row is column18, corresponding to one column less than the minimum column of the fourteenth block776.

FIG. 29is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

As shown at2900, subsequent to obtaining the block dimensions and location data for the fifteenth block778as shown at2810inFIG. 28, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fifteenth block778is unavailable, as shown at910inFIG. 9. The context for decoding the fifteenth block778may include the reconstructed image content of the third block754, the reconstructed image content of the twelfth block772, and the reconstructed image content of the eleventh block770, which may be identified as available. The fifteenth block778is shown at2900inFIG. 29with a stippled background to indicate that the image content for the fifteenth block778may be identified as available for coding a subsequently coded block. The image content for the fifteenth block778may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the fifteenth block778may be decoded prior to decoding the image content for the fourteenth block776.

Subsequent to identifying the image content for the fifteenth block778as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes blocks, as shown at930inFIG. 9. The stack may include the thirteenth block774and the fourteenth block776. As shown at2910, the fourteenth block776may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the fourteenth block776is unavailable, as shown at910inFIG. 9. The context for decoding the fourteenth block776may be the reconstructed image content of the fifteenth block778and the reconstructed image content of the eleventh block770, which may be identified as available. The fourteenth block776is shown at2910inFIG. 29with a stippled background to indicate that the image content for the fourteenth block776may be identified as available for coding a subsequently coded block. The image content for the fourteenth block776may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the fourteenth block776may be decoded prior to decoding the image content for the thirteenth block774.

FIG. 30is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

Subsequent to identifying the image content for the fourteenth block776as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes blocks, as shown at930inFIG. 9. The stack may include the thirteenth block774. As shown at3000, the thirteenth block774may be identified as the current block, popped or removed from the stack, and contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the thirteenth block774is unavailable, as shown at910inFIG. 9. The context for decoding the thirteenth block774may be the reconstructed image content of the tenth block768, the reconstructed image content of the eleventh block770, and the reconstructed image content of the fourteenth block776, which may be identified as available. The thirteenth block774is shown at3000with a stippled background to indicate that the image content for the thirteenth block774may be identified as available for coding a subsequently coded block. The image content for the thirteenth block774may be decoded, as indicated at920inFIG. 9, prior to, concurrent with, or subsequent to obtaining block dimensions and location data for subsequent blocks from the portion700. The image content for the thirteenth block774may be decoded prior to decoding subsequent blocks from the portion700.

As shown at3010, subsequent to identifying the image content for the thirteenth block774as available, contextual-lexicographic coding order with floating block-partitioning may include determining whether the stack1920includes blocks, as shown at930inFIG. 9. The stack1920may omit blocks. Subsequent to determining that the stack1920omits blocks, contextual-lexicographic coding order with floating block-partitioning may include obtaining block dimensions and location data for a sixteenth block780, such as by determining the block dimensions and location data at an encoder or decoding the block dimensions and determining the location data at a decoder. The sixteenth block780is shown as a 5×5 block. The sixteenth block780is shown with a solid white background to indicate that the reconstructed image content, such as reconstructed pixel values, for the sixteenth block780is unavailable. The unavailable image content for the sixteenth block780may be obtained, such as decoded at a decoder, subsequent to obtaining the block dimension and location data for the sixteenth block780.

Encoding the portion700may include identifying the block location and dimension data for the sixteenth block780and including the block dimension data or the block dimension data and the block location data in the output bitstream.

In some implementations, decoding the portion700may include decoding the block location data and the block dimension data for the sixteenth block780from the encoded bitstream.

In some implementations, the encoded bitstream may omit the block location information for the sixteenth block780and decoding the portion700may include determining the block location. Contextual-lexicographic coding order with floating block-partitioning may include using the minimum row constraint and the minimum column constraint, (min, min), as shown at940inFIG. 9. Decoding the block dimension data, such as shown at950inFIG. 9, for the sixteenth block780may include decoding a block height of five pixels and a block width of five pixels. Identifying the block location for the sixteenth block780may include using the available location context, the block location constraints, and the block dimensions, as shown at960inFIG. 9. For sixteenth block780, the available location context may include the tenth block768and the thirteenth block774. As shown at3000, prior to obtaining the block location and dimension data for sixteenth block780, the minimum available row is row11and the minimum available column within the minimum available row is column27.

FIG. 31is a block diagram of contextual-lexicographic coding order with floating block-partitioning, in accordance with implementations of this disclosure.

Subsequent to obtaining the block dimensions and location data for the sixteenth block780as shown at3010inFIG. 30, contextual-lexicographic coding order with floating block-partitioning may include determining whether the context for decoding the image content of the sixteenth block780is unavailable, as shown at910inFIG. 9. As shown at3100, the context for decoding the sixteenth block780may include the reconstructed image content of the tenth block768and the reconstructed image content of the thirteenth block774, which may be identified as available. The sixteenth block780is shown at3100inFIG. 31with a stippled background to indicate that the image content for the sixteenth block780may be decoded, as indicated at920inFIG. 9.

As used herein, the terms “optimal”, “optimized”, “optimization”, or other forms thereof, are relative to a respective context and are not indicative of absolute theoretic optimization unless expressly specified herein.

Further, for simplicity of explanation, although the figures and descriptions herein may include sequences or series of steps or stages, elements of the methods disclosed herein can occur in various orders and/or concurrently. Additionally, elements of the methods disclosed herein may occur with other elements not explicitly presented and described herein. Furthermore, one or more elements of the methods described herein may be omitted from implementations of methods in accordance with the disclosed subject matter.

The implementations of the transmitting computing and communication device100A and/or the receiving computing and communication device100B (and the algorithms, methods, instructions, etc. stored thereon and/or executed thereby) can be realized in hardware, software, or any combination thereof. The hardware can include, for example, computers, intellectual property (IP) cores, application-specific integrated circuits (ASICs), programmable logic arrays, optical processors, programmable logic controllers, microcode, microcontrollers, servers, microprocessors, digital signal processors or any other suitable circuit. In the claims, the term “processor” should be understood as encompassing any of the foregoing hardware, either singly or in combination. The terms “signal” and “data” are used interchangeably. Further, portions of the transmitting computing and communication device100A and the receiving computing and communication device100B do not necessarily have to be implemented in the same manner.

Further, in one implementation, for example, the transmitting computing and communication device100A or the receiving computing and communication device100B can be implemented using a computer program that, when executed, carries out any of the respective methods, algorithms and/or instructions described herein. In addition, or alternatively, for example, a special purpose computer/processor can be utilized which can contain specialized hardware for carrying out any of the methods, algorithms, or instructions described herein.

The transmitting computing and communication device100A and receiving computing and communication device100B can, for example, be implemented on computers in a real-time video system. Alternatively, the transmitting computing and communication device100A can be implemented on a server and the receiving computing and communication device100B can be implemented on a device separate from the server, such as a hand-held communications device. In this instance, the transmitting computing and communication device100A can encode content using an encoder400into an encoded video signal and transmit the encoded video signal to the communications device. In turn, the communications device can then decode the encoded video signal using a decoder500. Alternatively, the communications device can decode content stored locally on the communications device, for example, content that was not transmitted by the transmitting computing and communication device100A. Other suitable transmitting computing and communication device100A and receiving computing and communication device100B implementation schemes are available. For example, the receiving computing and communication device100B can be a generally stationary personal computer rather than a portable communications device and/or a device including an encoder400may also include a decoder500.

The above-described implementations have been described in order to allow easy understanding of the application are not limiting. On the contrary, the application covers various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structure as is permitted under the law.