US-12621453-B2 - Reducing the number of regular coded bins in entropy coding in video encoding and decoding

Abstract

To encode with CABAC, a non-binary syntax element value is mapped to a binary sequence (bin string), through a binarization process. A binary arithmetic coding engine encodes or decodes a bin, in a regular (context-based) mode and a bypass mode.

Inventors

• Fabrice Le Leannec
• Tangi POIRIER
• Ya Chen

Assignees

• INTERDIGITAL VC HOLDINGS, INC.

Dates

Publication Date

20260505

Application Date

20200304

Priority Date

20190311

Claims (20)

1. 1 . A method, comprising: decoding a plurality of binary symbols representing a syntax element, wherein one or more binary symbols at beginning of said plurality of binary symbols are entropy decoded using a bypass mode, and wherein the rest of said plurality of binary symbols is entropy decoded in a context-based mode; and obtaining said syntax element from said plurality of binary symbols, based on a binarization scheme.
2. 2 . The method of claim 1 , wherein said binarization scheme is a truncated Rice binarization scheme.
3. 3 . The method of claim 1 , wherein said syntax element indicates, from a set of weighting factors, a weighting factor for weighting one of two predictors when forming a weighted sum of said two predictors.
4. 4 . The method of claim 3 , wherein another weighting factor is obtained responsive to said weighting factor, said another weighting factor used in weighting another one of said two predictors when forming said weighted sum.
5. 5 . The method of claim 1 , wherein each binary symbol of said rest of said plurality of binary symbols uses a different context model.
6. 6 . A method, comprising: accessing a block to be encoded; and encoding a syntax element, wherein a plurality of binary symbols representing said syntax element are obtained based on a binarization scheme, wherein one or more binary symbols at beginning of said plurality of binary symbols are entropy encoded using a bypass mode, and wherein the rest of said plurality of binary symbols is entropy encoded in a context-based mode.
7. 7 . The method of claim 6 , wherein said binarization scheme is a truncated Rice binarization scheme.
8. 8 . The method of claim 6 , wherein said syntax element indicates, from a set of weighting factors, a weighting factor for weighting one of two predictors when forming a weighted sum of said two predictors.
9. 9 . The method of claim 8 , wherein another weighting factor is obtained responsive to said weighting factor, said another weighting factor used in weighting another one of said two predictors when forming said weighted sum.
10. 10 . The method of claim 6 , wherein each binary symbol of said rest of said plurality of binary symbols uses a different context model.
11. 11 . An apparatus, comprising one or more processors, wherein said one or more processors are configured to: decode a plurality of binary symbols representing a syntax element, wherein one or more binary symbols at beginning of said plurality of binary symbols are entropy decoded using a bypass mode, and wherein the rest of said plurality of binary symbols is entropy decoded in a context-based mode; and obtain said syntax element from said plurality of binary symbols, based on a binarization scheme.
12. 12 . The apparatus of claim 11 , wherein said binarization scheme is a truncated Rice binarization scheme.
13. 13 . The apparatus of claim 11 , wherein said syntax element indicates, from a set of weighting factors, a weighting factor for weighting one of two predictors when forming a weighted sum of said two predictors.
14. 14 . The apparatus of claim 13 , wherein another weighting factor is obtained responsive to said weighting factor, said another weighting factor used in weighting another one of said two predictors when forming said weighted sum.
15. 15 . The apparatus of claim 11 , wherein each binary symbol of said rest of said plurality of binary symbols uses a different context model.
16. 16 . An apparatus, comprising one or more processors, wherein said one or more processors are configured to: access a block to be encoded; and encode a syntax element, wherein a plurality of binary symbols representing a syntax element are obtained based on a binarization scheme, wherein one or more binary symbols at beginning of said plurality of binary symbols are entropy encoded using a bypass mode, and wherein the rest of said plurality of binary symbols is entropy encoded in a context-based mode.
17. 17 . The apparatus of claim 16 , wherein said binarization scheme is a truncated Rice binarization scheme.
18. 18 . The apparatus of claim 16 , wherein said syntax element indicates, from a set of weighting factors, a weighting factor for weighting one of two predictors when forming a weighted sum of said two predictors.
19. 19 . The apparatus of claim 18 , wherein another weighting factor is obtained responsive to said weighting factor, said another weighting factor used in weighting another one of said two predictors when forming said weighted sum.
20. 20 . The apparatus of claim 16 , wherein each binary symbol of said rest of said plurality of binary symbols uses a different context model.

Description

This application claims the benefit, under 35 U.S.C. § 371 of International Application No. PCT/US2020/021011, filed Mar. 4, 2020, which was published on Sep. 17, 2020, which claims the benefit of European Patent Application Nos. EP19305278.4 filed Mar. 11, 2019 and EP19305693.4 filed May 29, 2019. TECHNICAL FIELD The present embodiments generally relate to a method and an apparatus for video encoding or decoding, and more particularly, to a method and an apparatus for reducing the number of regular coded bins in entropy encoding and decoding. BACKGROUND To achieve high compression efficiency, image and video coding schemes usually employ prediction and transform to leverage spatial and temporal redundancy in the video content. Generally, intra or inter prediction is used to exploit the intra or inter picture correlation, then the differences between the original block and the predicted block, often denoted as prediction errors or prediction residuals, are transformed, quantized, and entropy coded. To reconstruct the video, the compressed data are decoded by inverse processes corresponding to the entropy coding, quantization, transform, and prediction. SUMMARY According to an embodiment, a method of video decoding is provided, comprising: decoding a plurality of binary symbols from a bitstream, wherein the first binary symbol of said plurality of binary symbols is entropy decoded using a context-based mode, and wherein each binary symbol following the first binary symbol is to be entropy decoded in a bypass mode; obtaining an index represented by said plurality of binary symbols, corresponding to a binarization scheme; and forming prediction for a block as a weighted sum of two predictors, wherein the index indicates respective weighting factors used in weighting said two predictors when forming said weighted sum. According to an embodiment, a method of video encoding is provided, comprising: accessing a block to be encoded; forming prediction for the block as a weighted sum of two predictors; and encoding an index to indicate respective weighting factors used in weighting said two predictors when forming said weighted sum, wherein said index is binarized, using a binarization scheme, into a plurality of binary symbols, wherein the first binary symbol of said plurality of binary symbols is entropy encoded using a context-based mode, and wherein each binary symbol following the first binary symbol is to be entropy encoded in a bypass mode. According to another embodiment, an apparatus for video decoding is provided, comprising one or more processors, wherein said one or more processors are configured to: decode a plurality of binary symbols from a bitstream, wherein the first binary symbol of said plurality of binary symbols is entropy decoded using a context-based mode, and wherein each binary symbol following the first binary symbol is to be entropy decoded in a bypass mode; obtain an index represented by said plurality of binary symbols, corresponding to a binarization scheme; and form prediction for a block as a weighted sum of two predictors, wherein the index indicates respective weighting factors used in weighting said two predictors when forming said weighted sum. According to another embodiment, an apparatus for video encoding is provided, comprising one or more processors, wherein said one or more processors are configured to: access a block to be encoded; form prediction for the block as a weighted sum of two predictors; and encode an index to indicate respective weighting factors used in weighting said two predictors when forming said weighted sum, wherein said index is binarized, using a binarization scheme, into a plurality of binary symbols, wherein the first binary symbol of said plurality of binary symbols is entropy encoded using a context-based mode, and wherein each binary symbol following the first binary symbol is to be entropy encoded in a bypass mode. According to another embodiment, an apparatus of video decoding is provided, comprising: means for decoding a plurality of binary symbols from a bitstream, wherein the first binary symbol of said plurality of binary symbols is entropy decoded using a context-based mode, and wherein each binary symbol following the first binary symbol is to be entropy decoded in a bypass mode; means for obtaining an index represented by said plurality of binary symbols, corresponding to a binarization scheme; and means for forming prediction for a block as a weighted sum of two predictors, wherein the index indicates respective weighting factors used in weighting said two predictors when forming said weighted sum. According to another embodiment, an apparatus of video encoding is provided, comprising: means for accessing a block to be encoded; means for forming prediction for the block as a weighted sum of two predictors; and means for encoding an index to indicate respective weighting factors used in weighting said two predictors when forming said weight