Texas Instruments Corporation

Massachusetts Institute of Technology

Vivienne Sze

Madhukar Budagavi

Minhua Zhou

Mehmet Umut Demircin

Do-Kyoung Kwon

Woo-Shik Kim

Akira Osamoto

Yasutomo Matsuba

Anantha P Chandrakasan

Vinay Sharma

Goksel Dedeoglu

Zhengdong Zhang

A method for encoding a video sequence is provided that includes entropy encoding syntax elements representative of transform coefficients generated as the video sequence is processed, wherein entropy encoding syntax elements representative of a transform coefficient includes binarizing the syntax elements representative of the transform coefficient to generate a plurality of binary symbols (bins), coding a portion of the plurality of bins in context coding mode, and coding a remaining portion of the plurality of bins in bypass coding mode. The method further includes reducing the number of bins that are coded in context coding mode for each transform coefficient in a plurality of subsequent transform coefficients that are entropy encoded after a specified number of transform coefficients have been entropy encoded.

Context adaptive binary arithmetic coding and bypass coding

A method for in-loop filtering in a video encoder is provided that includes determining filter parameters for each filtering region of a plurality of filtering regions of a reconstructed picture, applying in-loop filtering to each filtering region according to the filter parameters determined for the filtering region, and signaling the filter parameters for each filtering region in an encoded video bit stream, wherein the filter parameters for each filtering region are signaled after encoded data of a final largest coding unit (LCU) in the filtering region, wherein the in-loop filtering is selected from a group consisting of adaptive loop filtering and sample adaptive offset filtering.

Flexible region based sample adaptive offset (SAO) and adaptive loop filter (ALF)

A method for entropy encoding syntax elements of transform coefficient levels in a video encoder to generate a compressed video bit stream is provided that includes selecting a context for a first significant coefficient flag corresponding to a first transform coefficient level in a 32×32 transform block, wherein the first transform coefficient level is at a lowest frequency position in the 32×32 transform block, entropy encoding the first significant coefficient flag using the context, selecting the context for a second significant coefficient flag corresponding to a second transform coefficient level in a 16×16 transform block, wherein the second transform coefficient level is at a lowest frequency position in the 16×16 transform block, and entropy encoding the second significant coefficient flag using the context.

Simplified context selection for entropy coding of transform coefficient syntax elements

Techniques for context-adaptive binary arithmetic coding (CABAC) coding with a reduced number of context coded and/or bypass coded bins are provided. Rather than using only truncated unary binarization for the syntax element representing the delta quantization parameter and context coding all of the resulting bins as in the prior art, a different binarization is used and only part of the resulting bins are context coded, thus reducing the worst case number of context coded bins for this syntax element. Further, binarization techniques for the syntax element representing the remaining actual value of a transform coefficient are provided that restrict the maximum codeword length of this syntax element to 32 bits or less, thus reducing the number of bypass coded bins for this syntax element over the prior art.

Reducing context coded and bypass coded bins to improve context adaptive binary arithmetic coding (CABAC) throughput

A method and apparatus for encoding bit code utilizing context dependency simplification to reduce dependent scans. The method includes retrieving at least one 2 dimensional array of transform coefficient, transforming the at least one 2 dimensional array of transform coefficient to a 1 dimensional coefficient scanning using a diagonal scan in a fixed direction, utilizing the at least one 1 dimensional array of transform coefficients for context selection based on fewer than 11 neighbors, potentially selected based on scan direction, slice type, coding unit type and binarization, and performing arithmetic coding to generate coded bit utilizing context selection and binarization.

Method and apparatus for diagonal scan and simplified context selection for parallel entropy coding of significance map of transform coefficients

A method of entropy coding in a video encoder is provided that includes assigning a first bin to a first single-probability bin encoder based on a probability state of the first bin, wherein the first single-probability bin encoder performs binary arithmetic coding based on a first fixed probability state, assigning a second bin to a second single-probability bin encoder based on a probability state of the second bin, wherein the second single-probability bin encoder performs binary arithmetic coding based on a second fixed probability state different from the first fixed probability state, and coding the first bin in the first single-probability bin encoder and the second bin in the second single-probability bin encoder in parallel, wherein the first single-probability bin encoder uses a first rLPS table for the first fixed probability state and the second single-probability bin encoder uses a second rLPS table for the second fixed probability state.

Simplified binary arithmetic coding engine

A method for decoding an encoded video bit stream in a video decoder is provided that includes determining a scan pattern type for a transform block to be decoded, decoding a column position X and a row position Y of a last non-zero coefficient in the transform block from the encoded video bit stream, selecting a column-row inverse transform order when the scan pattern type is a first type, selecting a row-column inverse transform order when the scan pattern type is a second type, and performing one dimensional (1D) inverse discrete cosine transformation (IDCT) computations according to the selected transform order to inversely transform the transform block to generate a residual block.

Inverse transformation using pruning for video coding

A method for sample adaptive offset (SAO) filtering and SAO parameter signaling in a video encoder is provided that includes determining SAO parameters for largest coding units (LCUs) of a reconstructed picture, wherein the SAO parameters include an indicator of an SAO filter type and a plurality of SAO offsets, applying SAO filtering to the reconstructed picture according to the SAO parameters, and entropy encoding LCU specific SAO information for each LCU of the reconstructed picture in an encoded video bit stream, wherein the entropy encoded LCU specific SAO information for the LCUs is interleaved with entropy encoded data for the LCUs in the encoded video bit stream. Determining SAO parameters may include determining the LCU specific SAO information to be entropy encoded for each LCU according to an SAO prediction protocol.

Sample adaptive offset (SAO) parameter signaling

A method and apparatus for parallel context processing for example for high coding efficient entropy coding in HEVC. The method comprising retrieving syntax element relating to a block of an image, grouping at least two bins belonging to similar context based on the syntax element, and coding the grouped bins in parallel.

Context and bypass encoding video

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.

Acceleration of bypass binary symbol processing in video coding

Context adaptive binary arithmetic coding (CABAC) with scalable throughput and coding efficiency

A method and a video processor for preventing start code confusion. The method includes aligning bytes of a slice header relating to slice data when the slice header is not byte aligned or inserting differential data at the end of the slice header before the slice data when the slice header is byte aligned, performing emulation prevention byte insertion on the slice header, and combine the slice header and the slice data after performing emulation prevention byte insertion.

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Vivienne Sze