Patent Publication Number: US-2011064129-A1

Title: Video capture and generation at variable frame rates

Description:
CROSS-REFERENCE TO PRIORITY APPLICATION 
     The present application claims priority to U.S. Provisional Application No. 61/242,973, filed Sep. 16, 2009, which is incorporated herein in its entirety for all purposes. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates generally to video capturing devices; and, more particularly, video capture and generation at variable frame rates. 
     2. Related Art 
     Just a decade ago, digital video capturing devices such as digital video cameras and computers with attached digital video cameras were fairly uncommon. Video games with digital video contents were very basic in nature. Devices that were commercially available had very limited video resolution and generally produced extremely poor quality video. These devices did, however, have limited memory storage requirements. Today, digital video and gaming devices are capable of producing high quality video. High quality video capture, storage, and play however have necessitated large memory storage and data transfer requirements. 
     Video capturing systems employed in current digital video and gaming devices not only necessitate a large memory for storage but cause blurred moving images of fast moving scenes. For instance, a moving image at a standard frame rate results in blurred the moving images, e.g., when the subjects or backgrounds are moving at a very fast pace. Nonetheless, in all of these digital video and gaming devices growth, along with other necessary hardware growth, the demand for better quality moving images with smaller memory requirements has increased. Many compression techniques that save memory are available as of today; even though they are not helpful in eliminating some of the abovementioned problems either. 
     For instance, conventional systems typically sample (capture) video at a constant 24-30 frames a second, and each of those frames are often encoded using a standard such as MPEG, DIVX, AVI, etc. Such samples are at fixed frame rate spacing, e.g., 1/24 seconds, between adjacent frames. At times, because the subject being captured (typically real life objects) move slowly, such sampling rates are more than sufficient to satisfy a viewing eye. When the subjects move very fast, such sampling rates may be perceived as blurred upon display. Increasing the sampling rate correspondingly increases the amount of data. Thus, a standard frame rate is chosen to accept tolerable blurring of infrequent high speed motion, while providing excessively sufficient in-focus video for slower or stationary motion. This is also the situation for graphics generation from, for example, video games. 
     These and other limitations and deficiencies associated with the related art may be more fully appreciated by those skilled in the art after comparing such related art with various aspects of the present invention as set forth herein with reference to the figures. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to apparatus and methods of operation that are further described in the following Brief Description of the Drawings, the Detailed Description of the Invention, and the claims. Other features and advantages of the present invention will become apparent from the following detailed description of the invention made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a system diagram illustrating a plurality of devices constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output; 
         FIG. 2  is a block diagram illustrating a device constructed and operating according to one or more one or more embodiments of the present invention for producing variable frame rate video output; 
         FIG. 3A  is a block diagram illustrating components of a device constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output by altering capture/generation video frame rate; 
         FIG. 3B  is a block diagram illustrating components of a device constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output by parsing video frames of a fixed frame rate input; 
         FIG. 4  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention; 
         FIG. 5  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention; 
         FIG. 6  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention; 
         FIG. 7  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention; and 
         FIG. 8  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a system diagram illustrating a plurality of devices constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output. Illustrated in  FIG. 1  is a plurality of digital electronic video capturing/generation devices  151 . These devices  151  may include a unique video system  153 , a Personal Video Recorder (PVR)  155 , a Personal Data Assistant (PDA)  157 , a digital camera  161 , a cell phone  163 , a video game  165 , a laptop computer  167 , and an audio/visual system  169 . These devices include structure and perform operations according to one or more aspects of the present invention. These devices support communication via one or more communication networks  102  with each other and with remote devices that are not illustrated in  FIG. 1 . A generic structure of these devices is illustrated in  FIG. 2 . Particular structures of one or more of these devices are illustrated in  FIGS. 3A and 3B . Operations performed by these devices are illustrated in  FIGS. 4-8 . 
     Generally, one or more of these devices  151  is operable to produce a variable frame rate video output. The variable frame rate video output may be transmitted to another device via the communication networks  102 , stored locally, or displayed locally. Each of these devices  151  includes structure and performs operations to support communications. Some of these devices  151  are operable to capture video, e.g., video cameras or devices that include video cameras, some are operable to produce video based upon input received, e.g., video game  165 , and some are operable to process received/stored video. Each of these devices is operable to produce variable frame rate video output. 
     The manner in which the variable frame rate video output is produced differs from embodiment to embodiment. Generally, the frame rate may change over time and is based upon the content of video information captured/stored/displayed. By varying frame rate over time that is based upon the content over time, communication load and/or storage load is reduced. With some embodiments, the frame rate at which the video is captured varies over time based upon the video content. With other embodiments, video is captured, generated, or received at a fixed frame rate, the video is analyzed, and frames are discarded so that the frame rate of video output is varied. As the reader appreciates, output video may be encoded or unencoded, depending upon the embodiment. 
     Generally, with a first embodiment, a device  151  of  FIG. 1  generates an encoded video data stream and includes at least a variable frame rate capture system and a video encoder. The variable frame rate capture system captures a first sequence of video frames at a first frame rate. The variable frame rate capture system compares at least two neighboring frames of the first sequence of video frames to determine differences between the at least two neighboring frames. The variable frame rate capture system captures a second sequence of video frames at the first frame rate when a first comparison result is met. The variable frame rate capture system then captures a second sequence of video frames at a second frame rate that differs from the first frame rate when a second comparison result is met. Finally, the video encoder encodes the first sequence of video frames and the second sequence of video frames to produce the encoded video stream and time stamps video frames of the first set of successive video frames and the second set of successive video frames. 
     With some operations, the first sequence of video frames may include time stamps and the time stamps flow through encoding process. With other operations, the variable frame rate capture system captures a third sequence of video frames at a third frame rate that differs from both the first frame rate and the second frame rate when a third comparison result is met. With these other operations, the video encoder encodes the first sequence of video frames, the second sequence of video frames, and the third sequence of video frames to produce the encoded video stream. 
     With some of the devices  151 , the capturing may be performed by digital camera. With other of the devices, the variable frame rate capture system is a portion of an electronic video game and comparing at least two neighboring frames of the first sequence of video frames to determine difference between the at least two neighboring frames is based upon graphical element content of the at least two neighboring frames. 
     With other embodiments of the devices  151  of  FIG. 1 , the device includes a video input that receives a sequence of video frames at a first frame rate. A variable frame rate video encoder couples to the video input and the variable frame rate video encoder receives the sequence of video frames at the first frame rate from the video input. The variable frame rate video encoder compares at least two neighboring frames of the sequence of video frames to determine differences between the at least two neighboring frames. The variable frame rate video encoder partitions the sequence of video frames into a first sequential group of video frames and a second sequential group of video frames. Further, the variable frame rate video encoder selectively discards some video frames of the first sequential group of video frames such that the first sequential group of video frames has a second frame rate that is less than the first frame rate. Moreover, the variable frame rate video encoder encodes the first sequential group of video frames and the second sequential group of video frames to produce the video stream and time stamps the video frames of the video stream. 
     In some operations, the first sequential group of video frames has less relative inter-frame motion than does the second sequential group of video frames. With other operations, the variable frame rate video encoder partitions the second sequential group of video frames into a third sequential group of video frames and a fourth sequential group of video frames and the variable frame rate video encoder selectively discards some video frames of the third sequential group of video frames and the fourth sequential group of video frames such that the third sequential group of video frames and the fourth sequential group of video frames have differing frame rates. 
     In yet another embodiment of a device  151  of  FIG. 1 , the device includes a variable frame rate capture system and a video encoder. The variable frame rate capture system captures a first sequence of video frames at a first frame rate and the variable frame rate capture system compares at least two neighboring frames of the first sequence of video frames to determine difference between the at least two neighboring frames. The variable frame rate capture system then captures a second sequence of video frames at a second frame rate that is greater than the first frame rate. The variable frame rate capture system further captures a third sequence of video frames at a third frame rate that is less than the first frame rate. Finally, the video encoder encodes the first sequence of video frames, the second sequence of video frames, and the third sequence of video frames to produce the encoded video stream. The video encoder time stamps video frames of the first, second, and third sequence of video frames. Alternately, the variable frame rate capture system time stamps time stamps the video frames of the first, second, and third sequence of video frames. 
     In its operations, the variable frame rate capture system may step a capture rate from the first capture rate to the second capture rate. Alternately, the variable frame rate capture system steps a capture rate from the first capture rate to the third capture rate. In some embodiments, the variable frame rate capture system is a digital camera. Alternately, the variable frame rate capture system is a portion of an electronic video game and the variable frame rate capture system comparing at least two neighboring frames of the first sequence of video frames to determine difference between the at least two neighboring frames is based upon graphical element content of the at least two neighboring frames. 
       FIG. 2  is a block diagram illustrating a device constructed and operating according to one or more one or more embodiments of the present invention for producing variable frame rate video output. The device  151  includes one or more wireless interfaces  202 , one or more wired communication interfaces  204 , processing circuitry  206 , video processing circuitry/encoder circuitry  208 , and memory. The device  151  also may include video capture circuitry  212 , one or more user interfaces  214 , and may include audio/video presentation circuitry device(s)  216 . The wireless communication interfaces  204  may support cellular communications, Wireless Wire Area Network (WWAN) communications, e.g., WiMAX, Wireless Local Area Network (WLAN) communications, e.g., IEEE 802.11x communications, Wireless Personal Area Network (WPAN) communications, e.g., Bluetooth, infrared communications, millimeter wave communications, e.g., 60 GHz communications, satellite communications, and/or other wireless communications. The wired communication interface(s)  204  may support serial communications, e.g., USB, Fire wire, or parallel communications. The processing circuitry may include one or more system processors, digital signal processors, fixed processing circuitry, configurable processing circuitry, application specific processing circuitry, or other circuitry that is operable to process data and/or execute software instructions. The memory  210  may include one or more of RAM, ROM, magnetic storage, optical storage, flash memory, or another type of memory capable of storing data and software instructions. 
     The video processing circuitry/encoder circuitry  208  operates upon video frames to characterize and/or encode the video frames, according to an MPEG standard, a JPEG standard, or another video processing technique. The reader should appreciate that the operations of the present invention regarding video frames may be performed by the processing circuitry  206 , the video processing circuitry/encoder circuitry  208 , or a combination of these. In some constructs, the device  151  may not have dedicated video processing circuitry or encoder circuitry and a system processor or digital signal processor may perform all operations on the video frames. 
     The video capture circuitry  212  is operable to capture video frames. The video capture circuitry  212  may include a camera or may couple to an external camera. According to some embodiments of the present invention, the video capture circuitry  212  is operable to capture/receive video data a fixed frame rate. According to other embodiments of the present invention, the video capture circuitry  212  is operable to capture/receive vide data at variable frame rates. Such operations will be described further herein in detail. 
     The device  151  further includes one or more user interfaces such as a keypad, pointing device, cursor device, screen, speakers, microphone, or other user interface devices. The device  151  may also include audio/video presentation circuitry, interface(s), or devices  216 . These components  216  assist or actually present audio/video data to a user. In some embodiments, these components  216  produce output for presentation by one or more other components, such as external speakers, an external video display, and/or other components. 
       FIG. 3A  is a block diagram illustrating components of a device constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output by altering capture/generation video frame rate. The device  302  has components that may be included with one of the devices  151  of  FIGS. 1 and 2 . Generally, the device  302  includes a variable frame rate capture system  304 , a video encoder  306 , and processing circuitry  308  that communicatively couple to each other to implement one or more operations of the present invention. 
     The variable frame rate capture system  304  captures sequences of video frames at multiple frame rates depending upon the differences between the prior neighboring frames, and video encoder  306  encodes and time stamps the video frames to produce variable frame rate video stream. In other words, variable frame rate video generation device  302 , when working independently (as a standalone video capturing device) or incorporated into digital electronic video capturing systems (and electronic video games), generates a variable frame rate video stream that not only enhances the viewing video quality but also minimizes the storage size of the visual media content hence generated. 
     Typically, the first stage of digital electronic video capturing systems  157 ,  161 ,  163 ,  167 ,  155  and  153  consists of video capturing modules that sample the captured video content at a fixed sampling or frame rate. However, according to the present invention, the variable frame rate video generation device  302  captures video frames sampled at variable (stepwise) rates to produce a variable frame rate video stream. To produce the variable frame rate video stream (that enhances the viewing video quality and minimizes storage requirements), the variable frame rate capture system  304 , to begin with, samples a first sequence of video frames at a standard prefixed (first) sampling rate. For instance, a standard prefixed (first) sampling rate of the variable frame rate capture system  304  may also be anywhere between 24 to 30 video frames per second. Moreover, in the abovementioned instance, the first sequence of video frames may contain ten video frames (or more, if the processing time required to determine the next sampling rate, as described in the following paragraphs, is more), sampled at the abovementioned standard prefixed (first) sampling rate. 
     Then, the variable frame rate capture system  302  (the processing circuitry  308 , in conjunction with the video encoder  306 ) determines a quantitative difference between the neighboring video frames, by comparing at least two neighboring video frames of the first sequence of video frames. In the abovementioned instance, the variable frame rate capture system  302  may compare second and third video frames and then eighth and ninth video frames to determine an approximate average variation from the second to third frame and then eighth to ninth frame. Alternatively, the variable frame rate capture system  302  may compare each of the video frames with the first video frame. 
     Once an average difference is numerically (quantitatively) determined, the variable frame rate capture system  302  determines a new video frame rate for a second sequence of video frames. This is done by using a look up table that provides stepwise video frame rates that are dependent upon the numerical difference. For instance, the stepwise video frame rates may vary between 15 to 30 video frames per second, in a typical scenario. Then, the variable frame rate capture system  302  samples the second sequence of video frames at the abovementioned new video frame rate. In case of video game software, variable frame rates may be generated by considering past and/or forthcoming potential frame samples and with knowledge of motion vectors of graphic elements. 
     Finally, the video encoder  306  encodes the output of the variable frame rate capture system  304 , time stamps them (to be able to determine the time separations between the video frames) and delivers them to be displayed on a screen or to be stored in a storage unit of the digital electronic video capturing system  302  (within memory of device  151 ). 
     For example, when the captured video content changes rapidly because of moving objects or rapid panning, a higher video frame rate sampling is employed (to minimize blurring) by the variable frame rate capture system  304 . Similarly, when objects and scenes to be captured are relatively stationary, the frame rate is slowed down as it will be sufficient for the viewing eye. This difference in frame rates may involve linear or two or more lock-step changes. To carry out this approach in this embodiment, the digital electronic video capturing system is modified to generate frame sequences with time stamps associated with each frame so as to identify current frame separation. Hence, the variable frame rate capture system  304 , in the first embodiment of current depiction, directly modifies the capture rate at the imager based on past frame comparison. The operations of the device  302  are described further herein with reference to the flow charts of  FIGS. 4-8 . 
       FIG. 3B  is a block diagram illustrating components of a device constructed and operating according to one or more embodiments of the present invention for producing variable frame rate video output by parsing video frames of a fixed frame rate input. The variable frame rate video generation device  352  is incorporated into one or the devices  151  of  FIG. 1 . The variable frame rate video generation device  352  includes a video input  354 , a variable frame rate video encoder  356 , and processing circuitry  358 . The video input  354  receives sequences of video frames, the variable frame rate video encoder  356  groups the video frames and selectively discards some video frames of sequential groups, depending upon the differences between the prior neighboring frames, and then encodes and time stamps the video frames to produce variable frame rate video stream. The operations of the variable frame rate video encoder  356  are performed in conjunction with the processing circuitry  358 . In some operations, the video frame inspection and parsing is at least partially performed by the processing circuitry  358 . 
     The variable frame rate video generation device  352  may work as an independent unit (as a stand-alone video capturing device) or may be incorporated into digital electronic video capturing systems (and electronic video games). The variable frame rate video generation device  352  takes input from an external source and generates a variable frame rate video stream that enhances the viewing video quality and in addition minimizes storage size of the visual media content hence generated. An off the shelf digital electronic video capturing system may consist of video capturing modules that sample the captured video content at a fixed frame rate. They generate a fixed frame rate video stream and it is preferable for the current embodiment that they generate at a much higher sampling rate, such as, instead of typical 24 to 30 frames per second, a sampling rate of 50 or 100 frames per second. The variable frame rate video generation device  352 , while working in conjunction with these digital electronic video capturing systems (and electronic video games), generates video frames sampled at variable rates to produce a variable frame rate video stream. 
     Generally, the variable frame rate video encoder  352  receives a sequence of video frames at a first frame rate. A sequence may contain frames of few milliseconds to few seconds, for instance. Then, variable frame rate video encoder  356  and/or processing circuitry  358  determine quantitative differences between the neighboring video frames by comparing at least two neighboring video frames (at a fixed length of the received sequence of video frames). For instance, first and second video frames are compared, then, tenth and eleventh and so forth. Alternatively, the variable frame rate video encoder  356  and/or processing circuitry  358  may compare each of the video frames with the first video frame, within a sequence. 
     Once average numerical (quantitative) differences are determined, the variable frame rate video encoder  356  and/or processing circuitry partitions the sequence of video frames into a first sequential group of video frames and a second sequential group of video frames (alternatively, a plurality of groups, if a larger fixed length of the received sequence of video frames is considered). The partitioning is based upon the similarity between the frames within a group, such as, when the difference is minimal between few frames; they are taken as one group of frames. 
     Then, the variable frame rate video encoder  356  and/or processing circuitry  358  selectively discards some video frames of the first sequential group of video frames such that the first sequential group of video frames has a second frame rate that is less than the first frame rate. Similarly, the variable frame rate video encoder  356  and/or processing circuitry  358  may also selectively discard some video frames of the second (rest of the) sequential group(s) of video frames such that they have different frame rates of their own (that are less than the first frame rate). In the case of video game software, variable frame rates may be generated by considering past and/or forthcoming potential frame samples and with knowledge of motion vectors of graphic elements. 
     Finally, the variable frame rate video encoder  356  encodes the variable frame rate video content hence generated, time stamps them (to be able to determine the time separations between the video frames) and delivers them to be displayed on a screen or to be stored in a storage unit of the device  352 . 
       FIG. 4  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. The functionality of begins at a block  407  when the variable frame rate video generation device captures a first sequence of video frames at a first frame rate. The first frame rate may be within a range of typical capturing devices, that is, between 24 to 30 video frames per second or outside that range. Moreover, the sequence of video frames may be of few tens in numbers, for instance. 
     Next, at a block  409 , the variable frame rate video generation device compares one or more of neighboring video frames to determine the differences. When the number of video frames in the first sequence of video frames is only few, the variable frame rate video generation device may compare only one set of two neighboring video frames (say, first and second of the first sequence of video frames). When the numbers of video frames within the first sequence of video frames is more, more comparisons may be made. 
     At a next block  411 , the variable frame rate video generation device identifies a second frame rate for subsequent sequence video frames, based upon the differences at the block  409 . At a next block  413 , the variable frame rate video generation device captures a second (subsequent) sequence of video frames at the second frame rate. 
     At a final block  415 , the variable frame rate video generation device encodes and time stamps the first and second captured sequences of video frames to produce the video stream. 
       FIG. 5  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. The functionality begins at a block  507  when the variable frame rate video generation device captures a sequence of video frames at a fixed frame rate, for a predetermined period. The predetermined period may be duration of ten video frames or multiples of tens, for instance. And, a fixed frame rate may be a standard one, centered between the typical slowest video frame rate and highest video frame rate chosen. 
     At a next block  509 , the variable frame rate video generation device compares one or more of the neighboring video frames to determine the differences. The comparison may be done on pixel by pixel basis; for instance, in a matrix of two video frames; that is, a first pixel is compared with similarly positioned pixel of the neighboring video frame. Then, the differences are averaged out to determine a numerical value. Similar comparisons can be made between more video frames, when the sequence of video frames is long. 
     Based upon the differences, the variable frame rate video generation device, at a next block  511 , identifies a new frame rate. This can be done, for instance, by using a look up table that provides different frame rates for different averaged out differences (having their own numerical values). At a next block  513 , the variable frame rate video generation device captures, for a next predetermined period, a new sequence of video frames at the frame rate identified during the prior sequence. For instance, the averaged differences for a sequence of video frames, where there are barely any noticeable differences, are very low (and the frame rate can also be low). Similarly, for fast changing scenes, the averaged differences might be high (and the frame rate can also be high). 
     At a next block  517 , again, the variable frame rate video generation device compares one or more of the neighboring video frames to determine the differences, within this new sequence of video frames of the block  513 . The processes of the blocks  511 ,  513  and  517  continue as long as the variable frame rate video generation device is capturing video. 
     At a next block  515 , the variable frame rate video generation device time stamps the captured sequences of video frames of the blocks  511 ,  513  and  517 , to be able to identify the time separations between any two frames. At a final block  519 , the variable frame rate video generation device encodes the captured and time stamped sequences of video frames to produce the video stream. 
       FIG. 6  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. The functionality of begins at a block  607  when the variable frame rate video generation device receives a sequence of video frames at a first frame rate. As was the case with the embodiment of  FIG. 4 , the first frame rate may be within a typical value of between 24 to 30 video frames per second or outside that range. Moreover, the sequence of video frames may be of few tens in numbers, for instance. 
     At a next block  609 , the variable frame rate video generation device compares one or more of neighboring video frames to determine the differences. The differences may be determined by comparing only one set of two neighboring video frames (say, first and second of the first sequence of video frames), when the number of video frames in the sequence of video frames is only few; otherwise, more comparisons may be made and the differences may be averaged out. 
     The variable frame rate video generation device groups the received sequence of video frames based upon the averaged out differences at the block  609 , at a next block  611 . The grouping is done in such a way that the video frames within a group consist of video frames with minimal differences. At a next block  613 , the variable frame rate video generation device selectively discards some video frames from each of the groups to effectively alter the frame rates. At a final block  615 , the variable frame rate video generation device encodes and time stamps the first and second received sequences of video frames to produce the video stream. 
       FIG. 7  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. The functionality begins at a block  707  when the variable frame rate video generation device receives a sequence of video frames at a fixed frame rate, for a predetermined period. The predetermined period may be duration of ten video frames or multiples of tens, for instance. Moreover, the fixed frame rate may be a standard one, centered between the typical slowest video frame rate and highest video frame rate chosen. 
     At a next block  709 , the variable frame rate video generation device compares one or more of the neighboring video frames to determine the differences. Pixel by pixel comparisons may be averaged to determine a numerical value. Similar comparisons can be made between more video frames, when the sequence of video frames is long. 
     Based upon the differences, the variable frame rate video generation device, at a next block  711 , divides the sequence of video frames into two or more sequential groups that have very marginal or minimal differences. At a next block  713 , the variable frame rate video generation device selectively discards some video frames from each of the groups to effectively alter the frame rates. At a next block  717 , the variable frame rate video generation device compares one or more of the neighboring video frames to determine numerical values of the differences, within this new sequence of video frames of the block  713 . The processes of the blocks  711 ,  713  and  717  continue as long as the variable frame rate video generation device is receiving sequences of video frames. 
     At a next block  715 , the variable frame rate video generation device time stamps the received sequences of video frames of the blocks  711 ,  713  and  717 , to be able to identify the time separations between any two frames. At a final block  719 , the variable frame rate video generation device encodes the received and time stamped sequences of video frames to produce the video stream. 
       FIG. 8  is a flow diagram illustrating functionality of a variable frame rate video generation device according to one or more embodiments of the present invention. The functionality of begins at a block  807  when the variable frame rate video generation device receives a first sequence of video frames at a first frame rate. As is the case with the embodiment of the  FIG. 4 , the first frame rate may be within a range of typical video generation devices, that is, between 24 to 30 video frames per second or outside that range. Moreover, the sequence of video frames may be of few tens in numbers, for instance. 
     Next, at a block  809 , the variable frame rate video generation device compares one or more of neighboring video frames to determine a numerical value for the differences henceforth determined. The variable frame rate video generation device may compare only one set of two neighboring video frames, when the number of video frames in the first sequence of video frames is only few; alternatively, many more comparisons may be made, when the numbers of video frames within the first sequence of video frames is high. 
     Based upon the differences at the block  809 , at a next block  811 , the variable frame rate video generation device identifies a second frame rate (that is less than the first frame rate) for subsequent sequence video frames. At a next block  813 , the variable frame rate video generation device receives a second (subsequent) sequence of video frames. 
     At a next block  815 , the variable frame rate video generation device encodes and time stamps the first received sequence at the first frame rate to produce the video stream. At a final block  817 , the variable frame rate video generation device encodes and time stamps the second received sequence at the second frame rate to produce the video stream. 
     The terms “circuit” and “circuitry” as used herein may refer to an independent circuit or to a portion of a multifunctional circuit that performs multiple underlying functions. For example, depending on the embodiment, processing circuitry may be implemented as a single chip processor or as a plurality of processing chips Likewise, a first circuit and a second circuit may be combined in one embodiment into a single circuit or, in another embodiment, operate independently perhaps in separate chips. The term “chip”, as used herein, refers to an integrated circuit. Circuits and circuitry may comprise general or specific purpose hardware, or may comprise such hardware and associated software such as firmware or object code. 
     As one of ordinary skill in the art will appreciate, the terms “operably coupled” and “communicatively coupled,” as may be used herein, include direct coupling and indirect coupling via another component, element, circuit, or module where, for indirect coupling, the intervening component, element, circuit, or module does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As one of ordinary skill in the art will also appreciate, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two elements in the same manner as “operably coupled” and “communicatively coupled.” 
     The present invention has also been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claimed invention. 
     The present invention has been described above with the aid of functional building blocks illustrating the performance of certain significant functions. The boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality. To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claimed invention. 
     One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof. 
     Moreover, although described in detail for purposes of clarity and understanding by way of the aforementioned embodiments, the present invention is not limited to such embodiments. It will be obvious to one of average skill in the art that various changes and modifications may be practiced within the spirit and scope of the invention, as limited only by the scope of the appended claims.