Video coding/decoding apparatus which transmits different accuracy prediction levels

• US 5,731,840 A
• Filed: 03/08/1996
• Issued: 03/24/1998
• Est. Priority Date: 03/10/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Watanabe, Toshiaki, Ida, Takashi, Chujoh, Takeshi, Kikuchi, Yoshihiro, Dachiku, Kenshi, Yamaguchi, Noboru
• Primary Examiner(s): Britton, Howard W.
• Assistant Examiner(s): Le, Vu
• Application Number:
  US08/613,175
• Time in Patent Office: 746 Days
• Field of Search: 348/417, 348/418, 348/422, 348/412-416, 348/408, 348/402, 348/407, 386/27, 386/33, 386/37, 386/109, 386/111
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/20 using video object coding
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/517 by encoding
• CPC Class Codes: H04N 19/543 using regions
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 7/52 Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal assembling of a multiplex stream by combining a video stream with other content or additional data, remultiplexing of multiplex streams, insertion of stuffing bits into the multiplex stream, assembling of a packetised elementary stream at server side H04N21/236; disassembling of a multiplex stream, remultiplexing of multiplex streams, extraction or processing of Service Information, disassembling of packetised elementary stream at client side H04N21/434

Abstract

A video coding/decoding apparatus comprises a prediction circuit that divides an input video signal into large regions and small regions in a hierarchical fashion and produces a prediction signal by performing prediction region by region, a subtracter for generating a prediction error signal for a prediction signal at the lowest level, a DCT circuit for coding a prediction error signal, a quantization circuit and a variable-length encoder, a variable-length encoder for coding the prediction mode and motion vector information obtained at each level from the prediction circuit, and a multiplexer for multiplexing the code strings obtained from the variable-length encoder and dividing them into the upper-layer and lower-layer code strings to output the code strings obtained at the variable-length encoder particularly as upper-layer code strings.

Claims

1. A video coding apparatus comprising:

means for receiving an input video signal;

dividing means for dividing the input video signal into a plurality of first and a plurality of second regions smaller than the first regions;

prediction means for predicting each of the plurality of first regions and each of the plurality of second regions smaller than the first regions at respective prediction levels ranging from a first prediction level at which motion prediction is effected with a first accuracy to a second prediction level at which motion prediction is effected with a second accuracy higher than the first accuracy, for generating prediction signals corresponding to the first and second prediction levels, the first and second regions being obtained by dividing an input video signal at the respective levels;

prediction error generating means for generating a prediction error signal on the basis of the prediction signals obtained by said prediction means and the input video signal;

first coding means for coding the prediction error signal generated by said prediction error generating means to output first coded information;

second coding means for coding information on the prediction which is carried out at each of said prediction levels by said prediction means to output second coded information; and

code string output means for outputting the first and second coded information obtained by said first and second coding means in a hierarchical structure.

2. A video coding apparatus according to claim 1, wherein said prediction means generates a prediction signal including prediction mode information on the first regions and information indicating motion vectors thereof and a prediction signal containing prediction mode information on the second regions and information indicating motion vectors thereof, and said second coding means subjects the prediction mode information and motion vector information to variable-length coding.

3. A video coding apparatus according to claim 2, wherein said second coding means subjects the difference of the motion vectors for the regions adjacent to the first regions to variable-length coding, to output the second coded information.

4. A video coding apparatus according to claim 2, wherein said code string output means arranges the coded information in descending order of importance in decoding, to output the information.

5. A video coding apparatus according to claim 4, wherein said code string output means arranges the information in this order of prediction mode information and motion vector information.

6. A video coding apparatus according to claim 1, wherein said second coding means subjects the difference between the motion vectors for the first regions and the motion vectors for the second regions to variable-length coding, to output the second coded information.

7. A video decoding apparatus comprising:

receiving means for receiving upper-layer coded information and lower-layer coded information which are sent from a video coder and have been prediction-coded with a first accuracy and a second accuracy higher than the first accuracy, respectively;

first decoding means for obtaining a prediction error signal by decoding the upper-layer coded information and lower-layer coded information;

second decoding means for obtaining information on prediction by decoding the upper-layer coded information and the lower-layer coded information;

deciding means for deciding whether or not the prediction error signals decoded at said first and second decoding means and the information on prediction have been decoded correctly; and

picture generating means for reconstructing the video signal on the basis of said information decoded at said second decoding means, when said deciding means has decided that said first decoding means has not decoded the prediction error signal correctly.

8. A video decoding apparatus according to claim 7, wherein said picture generating means contains a memory for storing a reference picture corresponding to the preceding picture, prediction means for generating a prediction signal from at least one of the information from said second coding means and said prediction error signal and said reference picture, and means for generating said video signal on the basis of said prediction signal.

9. A video coding apparatus comprising:

means for receiving an input video signal;

dividing means for dividing the input video signal into a plurality of first and a plurality of second regions smaller than the first regions at the respective levels;

prediction means for predicting each of the plurality of first regions and each of the plurality of second regions at respective prediction levels ranging from a first prediction level at which motion prediction is effected with a first accuracy to a second prediction level at which motion prediction is effected with a second accuracy higher than the first accuracy, for generating prediction signals corresponding to the first and second prediction levels;

prediction error generating means for generating a prediction error signal on the basis of the prediction signals obtained by said prediction means and the input video signal;

first coding means for coding the prediction error signal generated by said prediction error generating means to output first coded information;

second coding means for coding information on the prediction which is carried out at each of said prediction levels by said prediction means to output second coded information; and

code string output means for outputting the first and second coded information in a hierarchical structure, and wherein

said prediction means obtains motion vectors for the first and second regions from the input video signal and reference video signal and on the basis of the motion vectors and generates a prediction signal corresponding to each of the prediction levels from the first prediction level to the second prediction level, and

said second coding means generates and codes the vector-quantized motion information corresponding to the motion vector as information on said prediction.

10. A video coding apparatus according to claim 9, wherein said second coding means subjects the difference of the motion vectors for the regions adjacent to the first regions to variable-length coding, to output the second coded information.

11. A video coding apparatus according to claim 9, wherein said second coding means subjects the difference between the motion vectors for the first regions and the motion vectors for the second regions to variable-length coding, to output the second coded information.

12. A video coding apparatus according to claim 9, wherein said code string output means arranges the coded information in descending order of importance in decoding, to output the information.

13. A video coding apparatus according to claim 12, wherein said code string output means arranges the information in this order of prediction mode information and motion vector information.

14. A video decoding apparatus comprising:

receiving means for receiving upper-layer coded information and lower-layer coded information which are sent from a video coder and have been prediction-coded with a first accuracy and a second accuracy higher than the first accuracy, respectively, the upper-layer coded information and lower-layer coded information containing coded motion information indicating vector-quantized motion vectors and coded prediction error information;

first decoding means for decoding the coded prediction error information from the upper-layer and lower-layer coded information;

second decoding means for obtaining the vector-quantized motion vector information by decoding the motion information in said upper-layer coded information and the lower-layer coded information;

deciding means for deciding whether or not the prediction error signals decoded at said first and second decoding means and the motion vector have been decoded correctly; and

picture generating means for reconstructing the video signal on the basis of the motion vector information decoded at said second decoding means, when said deciding means has decided that said first decoding means has not decoded the prediction error signal correctly.

15. A video decoding apparatus according to claim 14, wherein said picture generating means contains a memory for storing a reference picture corresponding to the preceding picture, prediction means for generating a prediction signal from at least one of the motion vector information from said second coding means and the prediction error signal and the reference picture, and means for generating the video signal on the basis of the prediction signal.

16. A video decoding apparatus according to claim 14, wherein said second decoding means contains a code book that is specified by index information serving as said coded motion information and outputs the corresponding motion vector information.

17. A video decoding apparatus according to claim 16, wherein said code book stores a plurality of motion vector candidates expressed with high pixel accuracy for motion vectors with small movement.

18. A video coding apparatus comprising:

means for receiving a video signal;

dividing means for dividing the input video signal into a plurality of blocks and further dividing the blocks into a plurality of regions in accordance with contents of pictures of the blocks;

prediction means having means for obtaining region information indicating each of the division shapes of the regions and motion vectors of the regions, and means for vector-quantizing a combination of the region shape information and the motion vectors of said regions, to generate a prediction signal;

prediction error generating means for generating a prediction error signal on the basis of the prediction signal and the video signal;

first coding means for coding the prediction error signal to output first coded information; and

second coding means for coding the vector-quantized motion information to output second coded information.

19. A video decoding apparatus comprising:

receiving means for receiving a coded prediction error signal based on a prediction signal and a video signal, the prediction signal being obtained by vector-quantizing a combination of region shape information indicating shapes of division regions divided in accordance with contents of pictures of blocks of the video signal;

first decoding means for decoding the coded prediction error signal;

second decoding means for decoding motion information obtained by combining the region shape information indicating the division shape of each region with the region'"'"'s motion vector for each region of the video signal and vector-quantizing the combination;

prediction means for generating a prediction signal by performing the motion compensation prediction of the video signal using the motion information decoded by said second decoding means; and

reconstructing means for reconstructing the video signal from said prediction signal and the prediction error signal decoded at said first decoding means.

20. A video coding apparatus which operates on an input video signal which has been divided by a dividing device into a plurality of first and a plurality of second regions smaller than the first regions, comprising:

prediction means for predicting each of the plurality of first regions and each of the plurality of second regions smaller than the first regions at respective prediction levels ranging from a first prediction level at which motion prediction is effected with a first accuracy to a second prediction level at which motion prediction is effected with a second accuracy higher than the first accuracy, for generating prediction signals corresponding to the first and second prediction levels, the first and second regions being obtained by dividing an input video signal at the respective levels;

prediction error generating means for generating a prediction error signal on the basis of the prediction signals obtained by said prediction means and the input video signal;

first coding means for coding the prediction error signal generated by said prediction error generating means to output first coded information;

second coding means for coding information on the prediction which is carried out at levels by said prediction levels by said prediction means to output second coded information; and

code string output means for outputting the first and second coded information obtained by said first and second coding means in two groups.

21. A video coding apparatus according to claim 20, wherein said second coding means outputs the second coded information including mode information indicating a prediction mode having a greatest importance.

22. A video coding apparatus according to claim 21, wherein the importance of said mode information indicates a seriousness of a deterioration which would result from an error in said mode information.

23. A video coding apparatus according to claim 20, wherein said second coding means outputs the second coded information including motion vector information.

24. A video coding apparatus according to claim 20, wherein said second coding means outputs the second coded information including mode information indicating a prediction mode having a greatest importance and motion vector information grouped in two groups.

25. A video coding apparatus according to claim 24, wherein the importance of said mode information indicates a seriousness of a deterioration which would result from an error in said mode information.