公开(公告)号：US11405631B2

公开(公告)日：2022-08-02

申请号：US16983342

申请日：2020-08-03

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Yaowu Xu ,  James Bankoski ,  Jia Feng

IPC: H04N19/00 ,  H04N19/51 ,  H04N19/196 ,  H04N19/182 ,  H04N19/176 ,  H04N19/513 ,  H04N19/433 ,  H04N19/55

Abstract: Decoding a current frame includes identifying a first reference frame and a second reference frame for decoding the current frame; storing reference motion vectors of reference blocks of the first reference frame, where other reference frames are used to decode the first reference frame; identifying motion trajectories that pass through the current frame by projecting the reference motion vectors of the reference blocks of the first reference frame onto the current frame using at least a third reference frame of the other reference frames, where the projecting identifies, for a first current block of the current frame a corresponding first reference block in the first reference frame, and a corresponding reference motion vector of the reference motion vectors is associated with the corresponding first reference block; and projecting the corresponding reference motion vector onto the second reference frame to obtain a second reference block in the second reference frame.

公开(公告)号：US11218737B2

公开(公告)日：2022-01-04

申请号：US16042261

申请日：2018-07-23

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Aki Kuusela ,  Stanislav Vitvitskyy ,  Yaowu Xu ,  Ching-Han Chiang ,  Dake He

IPC: H04N19/91 ,  H04N19/44 ,  H04N19/61 ,  H04N19/70

Abstract: Asymmetric probability model updating and entropy coding includes using different numbers of bits for storing probabilities of a probability model and for entropy coding symbols using that probability model. The probabilities of a probability model are updated according to values of syntax elements decoded from a bitstream. The probabilities are associated with possible values of the syntax elements and are stored using a first bit precision. Based on the updated probabilities, a second bit precision to use to entropy decode the syntax elements is determined. The second bit precision is less than the first bit precision. The syntax elements are then entropy decoded using the second bit precision, such as to produce quantized transform coefficients, which may be further processed and output to an output video stream. Using the first bit precision to entropy decode the syntax elements results in a lower compression throughput than using the second bit precision.

公开(公告)号：US11102477B2

公开(公告)日：2021-08-24

申请号：US16838544

申请日：2020-04-02

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Jingning Han ,  Ching-Han Chiang

IPC: H04N19/105 ,  H04N19/13 ,  H04N19/167 ,  H04N19/18 ,  H04N19/91

Abstract: A sign value of a DC coefficient of a current block is determined using neighbor blocks of the current block. First and second sign values are identified as respectively corresponding to an above neighbor block of the current block and a left neighbor block of the current block. A context value is calculated by applying a first weighting value to the first sign value and a second weighting value to the second sign value. The first weighting value is based on a boundary between the above neighbor block and the current block, and the second weighting value is based on a boundary between the left neighbor block and the current block. A probability value is selected based on the context value. The sign value of the DC coefficient of the current block is then determined using the probability model.

公开(公告)号：US20210144364A1

公开(公告)日：2021-05-13

申请号：US17090094

申请日：2020-11-05

Applicant: GOOGLE LLC

Inventor： Bohan Li ,  Yaowu Xu ,  Jingning Han

IPC: H04N19/105 ,  H04N19/139 ,  H04N19/573 ,  H04N19/172

Abstract: A motion field estimate determined using motion vector information of two or more reference frames of a current/encoded frame is used to derive a motion vector for inter-prediction of the current/encoded frame. Motion trajectory information, including concatenated motion vectors and locations of the current/encoded frame at which those concatenated motion vectors point, is determined by concatenating motion vectors of the reference frames. A motion field estimate is determined using the motion trajectory information and, in some cases, by interpolating unavailable motion vectors using neighbors. The motion field estimate is used to determine a co-located reference frame for the current/encoded frame, and an inter-prediction process is performed for the current/encoded frame using a motion vector derived using the co-located reference frame. During decoding, the motion field estimate may be determined using motion vectors signaled within a bitstream and without additional side information, thereby improving prediction coding efficiency.

公开(公告)号：US10986361B2

公开(公告)日：2021-04-20

申请号：US16456289

申请日：2019-06-28

Applicant: GOOGLE LLC

Inventor： Adrian William Grange ,  Ronald Sebastiaan Bultje ,  Yaowu Xu ,  Paul Gordon Wilkins

IPC: H04B1/66 ,  H04N19/52 ,  H04N19/46 ,  H04N19/105 ,  H04N19/117 ,  H04N19/124 ,  H04N19/13 ,  H04N19/159 ,  H04N19/61 ,  H04N19/172 ,  H04N19/176 ,  H04N19/182 ,  H04N19/184

Abstract: Decoding a video sequence may include generating decoded video data by decoding encoded video data from an encoded bitstream, wherein decoding the encoded video data includes identifying candidate reference motion vectors used to decode previously decoded blocks, identifying reconstructed pixel values from a block spatially adjacent to a current block in the current frame, for each candidate reference motion vector, determining a respective score based on a difference between the reconstructed pixel values and pixel values obtained using the candidate reference motion vector, identifying a candidate reference motion vector having the minimal score from the candidate reference motion vectors as the reference motion vector, decoding a motion vector from the encoded bitstream using the reference motion vector, and decoding the current block from the encoded bitstream using the motion vector.

公开(公告)号：US20200267391A1

公开(公告)日：2020-08-20

申请号：US16866591

申请日：2020-05-05

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Bohan Li ,  Jingning Han

IPC: H04N19/139 ,  H04N19/537 ,  H04N19/172 ,  H04N19/573 ,  H04N19/577 ,  H04N19/105

Abstract: Decoding a current block of a current frame includes selecting a first reference frame for forward inter prediction of the current frame; selecting a second reference frame for backward inter prediction of the current frame; generating an optical flow reference frame portion for inter prediction of the current block by performing an optical flow estimation using the first reference frame and the second reference frame, where the optical flow estimation produces a respective motion field for pixels of the current block; and performing a prediction process for the current block using the optical flow reference frame portion by: using a motion vector used to encode the current block to identify a reference block; adjusting boundaries of the reference block using a subpixel interpolation filter length; and identifying blocks encompassing pixels within the adjusted boundaries of the reference block.

公开(公告)号：US20200236375A1

公开(公告)日：2020-07-23

申请号：US16838529

申请日：2020-04-02

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Yaowu Xu

IPC: H04N19/436 ,  H04N19/82 ,  H04N19/14 ,  H04N19/117 ,  H04N19/86 ,  H04N19/176

Abstract: An apparatus for video coding using dual deblocking filter thresholds may include a processor generating a reconstructed frame by decoding an encoded bitstream and outputting the reconstructed frame. Decoding may include generating a decoded block by decoding a portion of the encoded bitstream, identifying a first deblocking threshold index from the encoded bitstream, identifying a second deblocking threshold index from the encoded bitstream, generating a reconstructed block based on the decoded block, and including the reconstructed block in the reconstructed frame. Generating the reconstructed block may include deblocking based on the first deblocking threshold index and the second deblocking threshold index.

公开(公告)号：US20200099956A1

公开(公告)日：2020-03-26

申请号：US16693438

申请日：2019-11-25

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  James Zern ,  Linfeng Zhang ,  Ching-Han Chiang ,  Yaowu Xu

IPC: H04N19/60 ,  H04N19/129 ,  H04N19/13 ,  H04N19/184 ,  H04N19/88

Abstract: A memory of an apparatus includes instructions executable by a processor to select a backward scan order for traversing, along scan-order anti-diagonal lines, a block of values related to the transform coefficients; select a template for entropy-coding the values, the template indicating, for a to-be-coded value, scan positions of already coded values, the scan positions arranged in at least two template anti-diagonal lines; maintain, for coding first values, where the first values are arranged along a current scan-order anti-diagonal line, a first line buffer and a second line buffer; for a current value of the current scan-order anti-diagonal line, determine a context using the first line buffer and the second line buffer, and entropy encode, in a compressed bitstream, the current value using the context; and replace one of the second line buffer or the first line buffer with the current scan-order anti-diagonal line.

公开(公告)号：US10567772B2

公开(公告)日：2020-02-18

申请号：US15646370

申请日：2017-07-11

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Jingning Han

IPC: H04N19/103 ,  H04N19/137 ,  H04N19/44 ,  H04N19/593 ,  H04N19/13 ,  H04N19/159 ,  H04N19/176 ,  H04N19/51 ,  H04N19/186 ,  H04N19/124

Abstract: Methods and apparatuses for coding a current block are disclosed. An apparatus for decoding a current block of size 8×8 including a memory and a processor is also disclosed. The processor configured to execute instructions stored in the memory to generate, for the current block, a luma block and a chroma block, divide the luma block into luma sub-blocks, and determine a respective prediction mode for each luma sub-block. The chroma block is of size 4×4, each luma sub-block is of size 4×4, and the respective prediction mode is an intra-mode or an inter-mode. The instructions also include instructions to, on condition that each of the respective prediction modes is the inter-mode, divide the chroma block into 2×2 chroma sub-blocks and determine a respective motion vector for each chroma sub-block.

公开(公告)号：US20200029098A1

公开(公告)日：2020-01-23

申请号：US16042261

申请日：2018-07-23

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Aki Kuusela ,  Stanislav Vitvitskyy ,  Yaowu Xu ,  Ching-Han Chiang ,  Dake He

IPC: H04N19/91 ,  H04N19/70 ,  H04N19/61 ,  H04N19/44

Abstract: Asymmetric probability model updating and entropy coding includes using different numbers of bits for storing probabilities of a probability model and for entropy coding symbols using that probability model. The probabilities of a probability model are updated according to values of syntax elements decoded from a bitstream. The probabilities are associated with possible values of the syntax elements and are stored using a first bit precision. Based on the updated probabilities, a second bit precision to use to entropy decode the syntax elements is determined. The second bit precision is less than the first bit precision. The syntax elements are then entropy decoded using the second bit precision, such as to produce quantized transform coefficients, which may be further processed and output to an output video stream. Using the first bit precision to entropy decode the syntax elements results in a lower compression throughput than using the second bit precision.