Patent Publication Number: US-2006018634-A1

Title: Creating a DVD compliant stream directly from encoder hardware

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims benefit to U.S. provisional application No. 60/578,288, filed on Jun. 10, 2004 entitled “Creating a DVD Compliant Stream Directly from Encoder Hardware,” which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to the compression of digital video signals and DVD recording and to the design of microcode for digital video encoders. More specifically, the present invention relates to a system, method and microcode instructions for generating a DVD compliant stream directly from an MPEG encoder.  
     BACKGROUND OF THE INVENTION  
      Development in the field of digital compression techniques and increases in the capacity of recording media are now enabling moving picture information to be compressed into digital data and recorded. DVD discs (which initials have been attributed to stand for “digital versatile disc” and “digital video disc”) are commonly used as a non-volatile storage medium for storing such audio and video image data. The audio and video data are typically formatted and encoded according to industry standard protocols before being stored on a DVD disc. Such standards include DVD VOB, VideoCD, CD-I, MPEG-1, MPEG-2, CD-ROM, or CD-DA.  
      Referring now to  FIG. 1 , there is shown a block diagram of a current prior art method for creating DVD disks. Typically, an analog signal, such as an analog signal from an antenna, a cable, a satellite receiver and the like, is converted into a digital signal by a conventional video analog-to-digital converter  102  and a conventional audio analog-to-digital converter  104  and inputted to an encoder  106 . The encoder  106  then compresses the digital signal into a compliant standard format such as an MPEG-2 bit stream and outputs the MPEG complant bit stream  114 . To create a DVD disk, third party DVD creation software  108  is required. The third party DVD disk software creates the various files required for creating the DVD disk, such as navigation VTS files, VMG files and the DVD VOB (MPEG-2) files. More specifically, the third party DVD disk creation software  108  takes the MPEG-2 compliant bit stream  114  as input and creates as output a DVD compliant stream  116 , such as a DVD VOB compliant stream, which may then be used to create a DVD disk  112 . This process is typically performed using a personal computer.  
      Referring now to  FIG. 2 , there is shown a block diagram of a conventional prior art digital video encoder  200 . Prior art video encoder  200  operates in accordance with video compression standards such as MPEG-2. Digital video encoder  200  comprises a global controller  202 , an SDRAM controller  204 , a video input buffer  206 , a video/audio compressor  207 , an encoder CPU  216  and a multiplexer  218 . Video/audio compressor  207  further comprises a motion estimator  208 , a digital signal processing core  210 , an audio processor  212  and a video bitstream processor  214 . Video input buffer  206  captures a video signal, which contains a current frame, or a plurality of current frames, to be encoded, and processes, accumulates and re-orders the frames according to a compression standard such as MPEG-2. The current frames are then transferred to motion estimation processor  208 . Reference frames which have already been encoded may also be transferred to the motion estimation processor  208 . Motion estimation processor  208  reads and compares both sets of frames, analyzes the motion of the video signal and transfers the motion analysis to digital signal processor core  210 .  
      Digital signal processor core  210  receives the current frames and according to the motion analysis received from motion estimation processor  208 , proceses and compresses the video signal. Digital signal processor  210  then transfers the compressed data to the video bitstream processor  214 . Digital signal processor  210  further reconstructs the reference frame and stores it in a reference memory. Video bitstream processor  214  encodes the compressed data and transfers an encoded video bitstream to an external post-encoding memory unit via SDRAM controller  204 . The external post-encoding memory unit may implement an output buffer (not shown) which stores the encoded video bitstream before it is transferred out of the encoder  200  as a compressed video output stream  220  to a target device. Encoder  200  may also contain an audio processor  212  for receiving and compressing an audio signal. The audio signal may then be multiplexed with the encoded video bitstream via multiplexer  218  and transferred out of the encoder  200  as a compressed video/audio output stream  220 .  
      The prior art method for compressing digital signals and creating DVD disks using third party software has several disadvantages. First, it is a cumbersome process requiring several hours to build a DVD disk. Creating the DVD VOB files required for the DVD disk is the largest bottle neck in the DVD disk creation process. The creation of the DVD disk requires first a conventional digital video encoder to convert an analog signal into an MPEG compliant bitstream, and then third party software and a personal computer which can then convert the MPEG stream outputted by the conventional digital video encoder into a DVD compliant stream. The DVD disk creation software must then demultiplex the MPEG compliant stream and then remultiplex the stream into the DVD VOB format.  
      Another disadvantage is that the creation of the DVD disk using conventional methods is not created in real time since it is dependent upon the third party software and upon software and hardware external to the conventional digital video encoder. Because a DVD burner requires the DVD VOB stream to create the DVD disk, there is at least a several hours delay from receiving the analog signal to creating the DVD disk.  
      Therefore, what is needed is a system and method which creates a DVD compliant stream directly from the encoder without third party software intervention and which can create DVD disks from an analog signal faster and more efficiently. It is also desirable to have a system and method for creating a DVD disk from an analog signal in real time.  
      Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.  
     SUMMARY OF THE INVENTION  
      The present invention comprises a system and method substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.  
       FIG. 1  illustrates a block diagram of a prior art system for creating DVDs.  
       FIG. 2  illustrates a block diagram of a prior art encoder.  
       FIG. 3  illustrates a block diagram of a system using an integrated encoder and DVD writer in accordance with one embodiment of the present invention.  
       FIG. 4  illustrates a block diagram of a system using an integrated encoder and DVD writer in accordance with another embodiment of the present invention.  
       FIG. 5  illustrates a block diagram of an integrated encoder and DVD writer in accordance with one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known processes and steps have not been described in detail in order not to unnecessarily obscure the present invention.  
      The invention generally pertains to a novel encoder for generating a DVD compliant stream from an analog signal. The present invention directly implements both a DVD VOB compliant stream and an MPEG compliant stream. In a preferred embodiment of the invention, this is achieved by providing microcode to be run by the integrated encoder and DVD writer of the present invention to generate a DVD VOB compliant stream directly from an analog signal according to the DVD VOB standards. In this embodiment, the system and method of the present invention advantageously provide an encoder with the ability to generate a DVD VOB compliant stream without third party software intervention thus allowing for a more efficient and faster process for generating a DVD VOB compliant stream and for creating DVD disks from an analog source in real time. The present invention also advantageously provides great flexibility in determining the output format for the inputted analog stream. For example, in one embodiment, the present invention may flexibly determine whether to output an MPEG compliant bit stream or a DVD VOB compliant stream or both.  
      Embodiments of the invention are discussed below with references to FIGS.  3  to  5 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments.  
      Referring now to  FIG. 3 , there is shown a block diagram of a system  300  using an integrated encoder and DVD writer in accordance with one embodiment of the present invention. In a preferred embodiment, the integrated encoder and DVD writer system comprises a BCM7040 or BCM7041 produced by Broadcom Corporation of Irvine, Calif. System  300  comprises a video analog-to-digital converter  302 , an audio analog-to-digital converter  304 , and an integrated encoder and DVD writer  306 . In this embodiment, an analog signal such as an analog signal from an antenna, a cable, a video camera or the like is inputted to the video analog-to-digital converter  302  and the audio analog-to-digital converter  304  and converted into a digital signal. The digital signal is then inputted into the integrated encoder and DVD writer  306 . One skilled in the art will realize that the present invention is not limited to inputting a digital signal into the integrated encoder and DVD writer  306 , but that the video analog-to-digital converter  302  and the audio analog-to-digital converter  304  may be intergated within the integrated encoder and DVD writer  306  thereby allowing an analog signal to be inputted directly to the integrated encoder and DVD writer  306 . The integrated encoder and DVD writer  306  then converts the digital video and audio signal into an MPEG compliant bit stream  308  and a DVD compliant stream  310  which may then be outputted directly from the integrated encoder and DVD writer  306  for further processing or storage. Thus, the present invention advantageously provides a system and method for generating a DVD compliant stream directly from an analog input signal which can then be outputted from the integrated encoder and DVD writer. The present invention also advantageously provides a system and method for generating a DVD compliant stream in real time.  
      Referring now to  FIG. 4 , there is shown a block diagram of a system  400  using an integrated encoder and DVD writer  406  in accordance with another embodiment of the present invention. In this embodiment, the integrated encoder and DVD writer  406  selects as a single output  408  either the MPEG compliant stream or the DVD compliant stream. More specifically, system  400  comprises a video analog-to-digital converter  402 , an audio analog-to-digital converter  404 , and an integrated encoder and DVD writer  406 . In a preferred embodiment, the integrated encoder and DVD writer system comprises a BCM7040 or BCM7041 produced by Broadcom Corporation of Irvine, Calif. In this embodiment, an analog signal such as an analog signal from an antenna, a cable, a video camera or the like is inputted to the video analog-to-digital converter  402  and the audio analog-to-digital converter  404  and converted into a digital signal. The digital signal is then inputted into the integrated encoder and DVD writer  406 . One skilled in the art will realize that the present invention is not limited to inputting a digital signal into the integrated encoder and DVD writer  406 , but that the video analog-to-digital converter  402  and the audio analog-to-digital converter  404  may be intergated within the integrated encoder and DVD writer  406  thereby allowing an analog signal to be inputted directly to the integrated encoder and DVD writer  406 . The integrated encoder and DVD writer then converts the digital video and audio signal into an MPEG compliant bit stream and a DVD VOB stream which may then be outputted directly from the integrated encoder and DVD writer  406 . The integrated encoder and DVD writer  406  further comprises an output controller or selector (not shown) which can then select or regulate which output stream  408 , either the MPEG stream or the DVD VOB stream, is outputted from the integrated encoder and DVD writer  406 . In yet another embodiment, the integrated encoder and DVD writer  406  may not automatically generate a DVD compliant stream, but may wait til receiving specific instructions for generating a DVD compliant stream. The present invention may also output either the DVD compliant stream or the MPEG stream for further processing or storage. Thus, the present invention advantageously provides great flexibility in determining the output format for the inputted analog stream.  
      Referring now to  FIG. 5 , there is shown a block diagram of an integrated encoder and DVD writer in accordance with one embodiment of the present invention. In a preferred embodiment, the integrated encoder and DVD writer  500  compresses a digital video signal in accordance with MPEG-2 video compression standards and converts the compressed MPEG-2 compliant bitstream into a DVD compliant bitstream in accordance with a DVD industry standard protocol such as DVD VOB. Integrated encoder and DVD writer  500  comprises a global controller  502 , an SDRAM controller  504 , a video input buffer  506 , a video/audio compressor  507 , a DVD writer engine  515 , an integrated encoder and DVD writer CPU  516  and a multiplexer  514 . Video/audio compressor  507  may further comprise a motion estimator, a digital signal processing core, an audio processor and a video bitstream processor for compressing the received input signal.  
      Video input buffer  506  captures an input video signal  518 , which contains a current frame, or a plurality of current frames, to be encoded, and processes, accumulates and re-orders the frames according to the standard required for the MPEG compression scheme. The current frames are then transferred to the video/audio compressor  507  where the digital video signal is compressed in accordance with a compression standard such as MPEG-2.  
      The MPEG compliant bitstream may then be transferred to the DVD writer or translator engine  515  which then converts or translates the MPEG compliant bitstream into a DVD compliant stream, such as a DVD VOB compliant stream. Thus, the DVD writer engine  515  directly implements the DVD VOB conversion process for the integrated encoder and DVD writer  500 . This unit may be instantiated separately within the integrated encoder and DVD writer  500  or may be integrated within another unit such as integrated encoder and DVD writer CPU  516 . In a preferred embodiment, integrated encoder and DVD writer CPU  516  comprises microcode for creating a compliant DVD VOB stream from the compressed video/audio output stream. In another embodiment, multiplexer  514  may select either the MPEG compliant bitstream or the DVD VOB compliant stream as the output  520  of the integrated encoder and DVD writer  500 .  
      While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.