Apparatus for segmenting encoded video signal for transmission

• US 5,168,356 A
• Filed: 12/20/1991
• Issued: 12/01/1992
• Est. Priority Date: 02/27/1991
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Acampora, Alfonse A., Siracusa, Robert J.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): LEE, MICHAEL
• Application Number:
  US07/814,207
• Time in Patent Office: 347 Days
• Field of Search: 358/133, 358/135, 358/136, 358/138, 358/141, 358/142, 358/12, 358/11, 375/122, 375/25, 375/27, 364/725, 371/2, 341/143, 370/118, 370/119, 370/110.1, 370/99
• US Class Current: 375/240.15
• CPC Class Codes: H04J 3/1605 Fixed allocated frame structures
• CPC Class Codes: H04N 19/37 with arrangements for assigning different transmission priorities to video input data or to video coded data
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4385 Multiplex stream processing, e.g. multiplex stream decrypting
• CPC Class Codes: H04N 7/015 High-definition television systems
• CPC Class Codes: H04N 7/54 the signals being synchronous H04N21/23602, H04N21/23614, H04N21/2365, H04N21/2368, H04N21/4341, H04N21/4342, H04N21/4347, H04N21/4348 take precedence

Abstract

A vide signal encoding system includes apparatus for segmenting encoded video data into transport blocks for signal transmission. The transport block format enhances signal recovery at the receiver by virtue of providing header data from which a receiver can determine re-entry points into the data stream on the occurrence of a loss or corruption of transmitted data. The number of re-entry points are maximized by providing secondary transport headers embedded within encoded video data in respective transport blocks.

Claims

1. In a video signal encoding system, wherein encoded video signal occurs, at least in part, as a succession of groups of data (e.g. slices), apparatus for segmenting encoded video signal data into transport blocks, comprising:

a source of encoded video signal data;

first means, responsive to said encoded video signal data, for deriving from said encoded video signal data, indicia identifying respective groups of said encoded video data and generating therefrom transport headers TH and RH, said transport header TH including a pointer to a relative position within a transport block at which said transport header RH is to be located;

second means, cooperating with said first means and responsive to said encoded video signal data, for multiplexing said transport header data and said encoded video signal data to form partial transport blocks of a predetermined amount of data; and

error encoding means, responsive to respective partial transport blocks, for generating error check codes for respective partial transport blocks, and appending said error check codes to corresponding partial transport blocks to form said transport blocks.

2. The apparatus set forth in claim 1 wherein respective transport blocks may include portions of consecutive groups of data, and said first and second means include means for embedding said transport header RH between said consecutive groups of data.

3. The apparatus set forth in claim 1 wherein said encoded video signal data is in the form of variable length codewords, and said apparatus further includes means responsive to said encoded video signal data, for arranging said variable length codewords into fixed length codewords.

4. In a video signal system for processing encoded video signal data conveyed in transport blocks, said transport blocks including a first transport header TH in a predetermined transport block location, a second transport header RH placed at variable locations within said transport blocks, which variable location is identified by a pointer in said first transport header, and an error check code located in a predetermined location in said transport block, apparatus comprising:

means for receiving and providing conveyed transport blocks;

error check means, responsive to said received transport blocks, for performing an error check on respective transport blocks in cooperation with associated error check codes, and providing an error indicating signal upon the detection of bit errors in said transport blocks;

control means, coupled to said error check means, for excising said error check codes from respective transport blocks, extracting said transport header TH from respective transport blocks and determining therefrom the location within said transport blocks of said transport headers RH, and extracting said transport header RH from respective transport blocks, and including means for providing encoded video signal included within said transport blocks exclusive of said extracted transport block headers and said error check codes.

5. The system set forth in claim 4 wherein said control means further includes means responsive to said error indicating signal for excising video signal transport blocks in which errors are detected.

6. The system set forth in claim 4 wherein at least a portion of the first transport header is Hamming code protected and the control means includes Hamming code error correction circuitry.

7. The system set forth in claim 4 wherein the signal processed by the system includes transport blocks of different signal types (e.g. video, audio etc.) and said control means includes means responsive to said first transport header for parsing the transport blocks of different signal types into respective signal paths.

8. The system set forth in claim 4 wherein the encoded video signal includes a sequence of transport blocks which have undergone forward error correction processing and forward error correction codes are appended thereto, and said means for receiving includes forward error processing circuitry, responsive to said forward error correction codes, for correcting at least a portion of errors incurred in conveying the encoded video signal data.

9. Apparatus for arranging compressed video data for transmission, comprising:

a source of compressed video data;

means responsive to said compressed video data for segmenting said video data into substantially equal blocks;

means responsive to said compressed video data for generating block header information related to the video data for respective blocks;

means for providing first error protection (e.g. HAMMING coding) to at least a portion of said header information;

means for concatenating said blocks of video data with respective header information;

means for providing second error protection (e.g. CRC coding)over concatenated blocks of video data and header information and appending error check bits thereto;

means for providing third error protection (e.g. forward error correction such as REED-SOLOMAN coding) over said concatenated video data and header information with error check bits appended, and appending further error check bits thereto; and

means for transmitting data provided with said third error protection.

10. The apparatus set forth in claim 9 wherein said video data is provided as variable length codewords and said apparatus further includes means for arranging said variable length codewords into codewords of predetermined numbers of bits.

11. The apparatus set forth in claim 9 wherein said means responsive to said compressed video data for generating block header information related to the video data for respective blocks, generates first header data TH to be located at a predetermined location in each block, and second header data RH to be imbedded between portions of video data within a block, and wherein said means for generating block header information includes means for generating indicia included in said first header for locating said second header.

12. In a video signal encoding system, wherein encoded video signal occurs, at least in part, as a succession of groups of data (e.g., slices), wherein each group includes a plurality of subgroups (e.g., blocks) of interdependent coded data representing a contiguous area of an image, apparatus for arranging encoded video signal data in transport blocks, comprising:

a source of encoded video signal data;

first means, responsive to said encoded video signal data, for dividing the encoded video data into segments of substantially equal amounts of data, respective segments representing encoded video data to be included in respective transport blocks, respective segments including video data from one or more of said groups, and wherein subgroups of data from ones of said groups may be in more than one segment;

second means, for generating transport headers including information to identify first occurring groups of data in respective segments, and for generating further headers including information identifying second occurring groups of data in respective segments which include data from first and second groups of data, said further headers to be located between first and second groups of data in respective transport blocks, said second means also generating, and including in respective transport headers, information indicating the location of said further headers in respective transport blocks;

third means, cooperating with said first and second means, for multiplexing respective transport headers with corresponding segments and further headers to form partial transport blocks, with respective transport headers located in a predetermined location in respective transport blocks; and

error encoding means, responsive to header information and encoded video data in respective partial transport blocks, for generating error check codes over respective partial transport blocks, and appending said error check codes to corresponding partial transport blocks to form said transport blocks.

13. The apparatus set forth in claim 12 wherein said second means generates and includes in said transport headers, information for detecting errors in at least a portion of said transport headers.

14. The apparatus set forth in claim 13 further including forward error check means (e.g., a REED-SOLOMAN coder) for generating error detection/correction codes over said transport blocks, and appending said error detection/correction codes to the blocks of data over which the error detection/correction codes were generated.

15. A system for receiving conveyed encoded video data occurring as a sequence of transport blocks, respective transport blocks including one or more of successively occurring groups of video data, wherein each group includes a plurality of subgroups (e.g., blocks) of interdependent coded data and each group represents a contiguous area of an image, and wherein subgroups of ones of said groups of video data may be included in successive transport blocks;

respective transport blocks including transport headers for identifying video data from a first occurring group of data in respective transport blocks, and information indicating the location of further headers in a respective transport block, said further headers identifying second occurring groups of data in respective transport blocks, said transport blocks also including respective error check codes for detecting data errors incurred during signal conveyance, said system comprising;

means for detecting said conveyed encoded video data and providing respective transport blocks;

error detection means, responsive to said error check codes for detecting the presence or absence of errors in respective transport blocks, excising transport blocks which include errors, and passing transport blocks which are free of errors;

means, responsive to error free transport blocks, for separating transport headers, and further headers from encoded video data; and

means, responsive to separated transport headers, for excising video data from error free transport blocks which video data corresponds to data included in a group of data occurring in part in said error free transport block and in part in a preceding transport block which included a detected error.

16. The system set forth in claim 15 wherein the encoded video data is conveyed in high and low priority channels of transport blocks of interdependent video data, with respective groups of data being conveyed in part in the low priority channel and in part in the high priority channel, and said means, responsive to separated transport headers, for excising video data from error free transport blocks, includes means for excising groups of error free video data in the low priority channel corresponding to groups of data in the high priority channel which have been excised.

17. A system for receiving conveyed encoded video data occurring as a sequence of transport blocks, respective transport blocks including one or more of successively occurring groups of video data each of which represents a contiguous area of an image, wherein each group includes a plurality of subgroups (e.g., blocks) of interdependent coded data, and wherein subgroups of ones of said groups of video data may be included in successive transport blocks;

respective transport blocks including transport headers for identifying video data from a first occurring group of data in respective transport blocks, and information indicating the location of further headers in a respective transport block, said further headers identifying second occurring groups of data in respective transport blocks, said transport blocks also including respective error check codes for detecting data errors incurred during signal conveyance, said system comprising;

means for detecting said conveyed encoded video data and providing respective transport blocks;

error detection means, responsive to said error check codes for detecting the presence or absence of errors in respective transport blocks, excising transport blocks which include errors, and passing transport blocks which are free of errors;

means, responsive to error free transport blocks, for separating transport headers, said further headers and encoded video data from the detected transport blocks; and

means, responsive to separated transport headers, said further headers and encoded video data for decoding said encoded video data.