Entropy coding of interleaved sub-blocks of a video block

• US 8,483,282 B2
• Filed: 10/08/2008
• Issued: 07/09/2013
• Est. Priority Date: 10/12/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Karczewicz, Marta, Ye, Yan
• Primary Examiner(s): Smithers, Matthew
• Application Number:
  US12/247,788
• Publication Number:
  US 20090097568A1
• Time in Patent Office: 1,735 Days
• Field of Search: 375/240.23
• US Class Current: 375/240.23
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• 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

Abstract

This disclosure describes techniques for entropy coding of video blocks, and proposes a syntax element that may promote coding efficiency. The syntax element may identify a number of non-zero value sub-blocks within a video block, wherein the non-zero value sub-blocks comprise sub-blocks within the video block that include at least one non-zero coefficient. A method of coding a video block may comprise coding the syntax element, generating the non-zero value sub-blocks of the video block, and entropy coding the non-zero value sub-blocks.

Claims

1. A method of encoding a video block, the method comprising:

scanning the video block to define a one-dimensional vector of coefficients;

dividing the one-dimensional vector of coefficients to define a set of one-dimensional vectors of sub-blocks of the video block;

coding a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

interleaving coefficients of the non-zero value sub-blocks to define interleaved sub-blocks;

entropy coding the interleaved sub-blocks; and

skipping entropy coding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero.

2. The method of claim 1, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

3. The method of claim 1, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

4. The method of claim 1, wherein entropy coding the interleaved sub-blocks comprises performing at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on coefficients of the non-zero value sub-blocks.

5. An apparatus comprising an encoder configured to:

scan a video block to define a one-dimensional vector of coefficients;

divide the one-dimensional vector of coefficients to define a set of one-dimensional vectors of sub-blocks of the video block;

code a syntax element that defines a number of non-zero value sub-blocks of a video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

interleave coefficients of the non-zero value sub-blocks to define interleaved sub-blocks;

entropy code the interleaved sub-blocks; and

skip entropy coding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero.

6. The apparatus of claim 5, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

7. The apparatus of claim 5, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

8. The apparatus of claim 5, wherein the encoder performs at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on coefficients of the interleaved sub-blocks.

9. The apparatus of claim 5, wherein the apparatus comprises one of an integrated circuit and a microprocessor.

10. A non-transitory computer-readable storage medium having stored thereon instructions that upon execution in a video encoding device cause the device to code a video block, wherein the stored instructions cause the device to:

scan the video block to define a one-dimensional vector of coefficients;

divide the one-dimensional vector of coefficients to define a set of one-dimensional vectors of sub-blocks of the video block;

code a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

interleave coefficients of the non-zero value sub-blocks to define interleaved sub-blocks;

entropy code the interleaved sub-blocks; and

skip entropy coding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero.

11. The computer-readable storage medium of claim 10, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

12. The computer-readable storage medium of claim 10, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

13. The computer-readable storage medium of claim 10, wherein the instructions cause the device to:

perform at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on coefficients of the interleaved sub-blocks.

14. A device comprising:

means for scanning a video block to define a one-dimensional vector of coefficients;

means for dividing the one-dimensional vector of coefficients to define a set of one-dimensional vectors of sub-blocks of the video block;

means for coding a syntax element that defines a number of non-zero value sub-blocks of a video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

means for interleaving coefficients of the non-zero value sub-blocks to define interleaved sub-blocks;

means for entropy coding the interleaved sub-blocks; and

means for skipping entropy coding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero.

15. The device of claim 14, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

16. The device of claim 14, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

17. The device of claim 14, wherein the means for entropy coding the interleaved sub-blocks comprises means for performing at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on coefficients of the interleaved sub-blocks.

18. A device comprising:

an encoder configured to;

scan the video block to define a one-dimensional vector of coefficients;

divide the one-dimensional vector of coefficients to define a set of one-dimensional vectors of sub-blocks of the video block;

encode a syntax element that defines a number of non-zero value sub-blocks of a video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

interleave coefficients of the non-zero value sub-blocks to define interleaved sub-blocks;

entropy encode the interleaved sub-blocks; and

skip entropy encoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero; and

a wireless transmitter that sends a bitstream comprising the entropy encoded interleaved sub-blocks and the syntax element.

19. A device comprising:

a wireless receiver that receives a bitstream comprising a set of interleaved and entropy coded sub-blocks and a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient; and

a decoder configured to;

entropy decode the interleaved and entropy coded sub-blocks to define interleaved sub-blocks;

skip entropy decoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero;

generate one or more zero-value sub-blocks based on the syntax element, wherein the received bitstream does not include the zero-value sub-blocks;

generate a one-dimensional vector of coefficients based on the interleaved sub-blocks and the one or more zero value sub-blocks; and

inverse scan the one-dimensional vector of coefficients to define a two-dimensional representation of the video block.

20. A method of decoding a video block, the method comprising:

receiving a bitstream comprising a set of interleaved and entropy coded sub-blocks and a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

entropy decoding the interleaved and entropy coded sub-blocks to define interleaved sub-blocks;

skipping entropy decoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero;

generating one or more zero-value sub-blocks based on the syntax element, wherein the received bitstream does not include the zero-value sub-blocks;

generating a one-dimensional vector of coefficients based on the interleaved sub-blocks and the one or more zero-value sub-blocks; and

inverse scanning the one-dimensional vector of coefficients to define a two-dimensional representation of the video block.

21. The method of claim 20, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

22. The method of claim 20, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

23. The method of claim 20, wherein entropy decoding the interleaved and entropy coded sub-blocks comprises performing at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on the interleaved and entropy coded sub-blocks.

24. An apparatus comprising a decoder configured to:

receive a bitstream comprising a set of interleaved and entropy coded sub-blocks and a syntax element that defines a number of non-zero value sub-blocks of a video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

entropy decode the interleaved and entropy coded sub-blocks to define interleaved sub-blocks;

skip entropy decoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero;

generate one or more zero-value sub-blocks based on the syntax element, wherein the received bitstream does not include the zero-value sub-blocks;

generate a one-dimensional vector of coefficients based on the interleaved sub-blocks and the one or more zero value sub-blocks; and

inverse scan the one-dimensional vector of coefficients to define a two-dimensional representation of the video block.

25. The apparatus of claim 24, wherein the syntax element defines both the number of non-zero value sub-blocks and a number of zero-value sub-blocks that have all coefficients equal to zero.

26. The apparatus of claim 24, wherein the video block comprises one of an 8 by 8 video block comprising 64 coefficients and a 16 by 16 video block comprising 256 coefficients, and wherein the sub-blocks comprise 4 by 4 blocks comprising 16 coefficients.

27. The apparatus of claim 24, wherein the decoder performs at least one of content adaptive variable length coding (CAVLC) or context adaptive binary arithmetic coding (CABAC) on the interleaved and entropy coded sub-blocks.

28. The apparatus of claim 24, wherein the apparatus comprises one of an integrated circuit and a microprocessor.

29. A non-transitory computer-readable storage medium having stored thereon instructions that upon execution in a video decoding device cause the device to decode a video block, wherein the instructions cause the device to:

receive a bitstream comprising a set of interleaved and entropy coded sub-blocks and a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

entropy decode the interleaved and entropy coded sub-blocks to define interleaved sub-blocks;

skip entropy decoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero;

generate one or more zero-value sub-blocks based on the syntax element, wherein the received bitstream does not include the zero-value sub-blocks;

generate a one-dimensional vector of coefficients based on the interleaved sub-blocks and the one or more zero value sub-blocks; and

inverse scan the one-dimensional vector of coefficients to define a two-dimensional representation of the video block.

30. A device comprising:

means for receiving a bitstream comprising a set of interleaved and entropy coded sub-blocks and a syntax element that defines a number of non-zero value sub-blocks of the video block, wherein the non-zero value sub-blocks include at least one non-zero coefficient;

means for entropy decoding the interleaved and entropy coded sub-blocks to define interleaved sub-blocks;

means for skipping entropy decoding of zero-value sub-blocks, wherein zero-value sub-blocks comprise sub-blocks of the video block that have all coefficients equal to zero;

means for generating one or more zero-value sub-blocks based on the syntax element, wherein the received bitstream does not include the zero-value sub-blocks;

means for generating a one-dimensional vector of coefficients based on the interleaved sub-blocks and the one or more zero-value sub-blocks; and

means for inverse scanning the one-dimensional vector of coefficients to define a two-dimensional representation of the video block.