Acceleration of bypass binary symbol processing in video coding

• US 10,123,053 B2
• Filed: 05/23/2012
• Issued: 11/06/2018
• Est. Priority Date: 05/23/2011
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sze, Vivienne, Budagavi, Madhukar
• Primary Examiner(s): Czekaj, Dave
• Assistant Examiner(s): Abimbola, Kehinde O
• Application Number:
  US13/478,899
• Publication Number:
  US 20120300839A1
• Time in Patent Office: 2,358 Days
• Field of Search: 375240
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• 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 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

A method for encoding a video sequence in a video encoder to generate a compressed video bit stream is provided that includes binarizing a plurality of syntax elements, wherein each binarized syntax element comprises a string of one or more binary symbols (bins), wherein a bin is one selected from a context-coded bin and bypass bin, encoding the context-coded bins of the binarized syntax elements using binary arithmetic encoding, and adding the bypass bins of the binarized syntax elements to the compressed video bit stream with no encoding.

Claims

1. A method for encoding a video sequence in a video encoder to generate a compressed video bit stream, the method comprising:

binarizing a plurality of syntax elements to produce a plurality of binarized syntax elements, the plurality of binarized syntax elements including one or more context-coded binary symbols (bins) and one or more bypass bins;

encoding the context-coded bins of the binarized syntax elements using binary arithmetic encoding;

adding the encoded context-coded bins to the compressed video bit stream; and

adding the bypass bins of the binarized syntax elements to the compressed video bit stream without arithmetically encoding the bypass bins.

2. The method of claim 1,

wherein the compressed video bit stream comprises a bypass bit stream and a coded bit stream, and

wherein using binary arithmetic encoding comprises writing output of the binary arithmetic encoding of the context-coded bins to the coded bit stream, and

wherein adding the bypass bins comprises writing the bypass bins to the bypass bit stream with no encoding.

3. The method of claim 1,

wherein using binary arithmetic encoding comprises writing output of the binary arithmetic encoding to the compressed video bit stream, and

wherein adding the bypass bins comprises:

determining that a bin is a bypass bin;

buffering the bypass bin in a bypass buffer; and

writing the bypass bin from the bypass buffer to the compressed video bit stream when a predetermined number of bits is output by the binary arithmetic encoding of the context-coded bins after the bypass bin is buffered.

4. The method of claim 3, wherein the predetermined number of bits is nine.

5. The method of claim 3, wherein at least one more bypass bin is buffered in the bypass buffer before the predetermined number of bits is output.

6. The method of claim 5, wherein the bypass bin is comprised in a first binarized syntax element and the at least one more bypass bin is comprised in a second binarized syntax element.

7. The method of claim 1, wherein adding the bypass bins comprises multiplexing the bypass bins with a sub-bitstream output by the binary arithmetic encoding of the context-coded bins to generate the compressed video bit stream.

8. A method for decoding a compressed video bit stream in a video decoder, the method comprising:

determining a type of a syntax element encoded in the compressed bit stream, wherein the encoded syntax element comprises a plurality of context-coded binary symbols (bins) and a plurality of bypass bins;

reading the plurality of bypass bins from the compressed video bit stream with no decoding;

decoding the plurality of context-coded bins from the compressed video bit stream using binary arithmetic decoding; and

debinarizing the plurality of context-coded bins and the plurality of bypass bins to regenerate the syntax element.

9. The method of claim 8,

wherein the compressed video bit stream comprises a bypass bit stream and a coded bit stream, and

wherein using binary arithmetic decoding comprises reading bits from the coded bit stream, and

wherein reading the plurality of bypass bins comprises reading bypass bins from the bypass bit stream.

10. The method of claim 8,

wherein using binary arithmetic decoding comprises reading bits corresponding to a binary arithmetic encoding of the context-coded bins from the compressed video bit stream, and

wherein reading the plurality of bypass bins comprises:

determining that a next bin to be decoded is a bypass bin; and

reading the bypass bin from a location in the compressed video bit stream that is a predetermined number of bits after a most significant bit of a current offset of the binary arithmetic decoding.

11. The method of claim 10, wherein the predetermined number of bits is nine.

12. The method of claim 8, wherein the compressed video bit stream comprises bypass bins of a plurality of binarized syntax elements multiplexed with a sub-bitstream of binary arithmetic encoded context-coded bins of the plurality of binarized syntax elements.

13. A video coding apparatus comprising:

a processor; and

a memory coupled to the processor, wherein the memory is configured to store instructions that, when executed by the processor, cause the processor to;

binarize a plurality of syntax elements to produce a plurality of binarized syntax elements, the plurality of binarized syntax elements including one or more context-coded binary symbols (bin) and one or more bypass bins;

encode the context-coded bins of the binarized syntax elements using binary arithmetic encoding;

add the encoded context-coded bins to a compressed video bit stream; and

add the bypass bins of the binarized syntax elements to the compressed video bit stream without arithmetically encoding the bypass bins.

14. The video coding apparatus of claim 13,

wherein the compressed video bit stream includes a bypass bit stream and a coded bit stream, and

wherein using binary arithmetic encoding includes writing output of the binary arithmetic encoding of the context-coded bins to the coded bit stream, and

wherein the instructions that cause the processor to add the bypass bins include instructions that cause the processor to add the bypass bins to the bypass bit stream with no encoding.

15. The video coding apparatus of claim 13,

wherein using binary arithmetic encoding comprises writing output of the binary arithmetic encoding to the compressed video bit stream, and

wherein the instructions that cause the processor to add the bypass bins include instructions that cause the processor to:

determine that a bin is a bypass bin;

buffer the bypass bin in a bypass buffer; and

write the bypass bin from the bypass buffer to the compressed video bit stream when a predetermined number of bits is output by the binary arithmetic encoding of the context-coded bins after the bypass bin is buffered.

16. The video coding apparatus of claim 15, wherein the predetermined number of bits is nine.

17. The video coding apparatus of claim 15, wherein at least one more bypass bin is buffered in the bypass buffer before the predetermined number of bits is output.

18. The video coding apparatus of claim 17, wherein the bypass bin is comprised in a first binarized syntax element and the at least one more bypass bin is comprised in a second binarized syntax element.

19. The video coding apparatus of claim 13, wherein the instructions that cause the processor to add the bypass bins include instructions that cause the processor to multiplex the bypass bins with a sub-bitstream output by the binary arithmetic encoding of the context-coded bins to generate the compressed video bit stream.