公开(公告)号：US20220264109A1

公开(公告)日：2022-08-18

申请号：US17738105

申请日：2022-05-06

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Bohan Li ,  Jingning Han

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

Abstract: Motion prediction using optical flow is determined to be available for a current frame in response to determining that a reference frame buffer includes, with respect to the current frame, a forward reference frame and a backward reference frame. A flag indicating whether a current block is encoded using optical flow is decoded. Responsive to determining that the flag indicates that the current block is encoded using optical flow, a motion vector is decoded for the current block; a location of an optical flow reference block is identified within an optical flow reference frame based on the motion vector; subsequent to identifying the location of the optical flow reference block, the optical flow reference block is generated using the forward reference frame and the backward reference frame without generating the optical flow reference frame; and the current block is decoded based on the optical flow reference block.

公开(公告)号：US11350102B2

公开(公告)日：2022-05-31

申请号：US16866591

申请日：2020-05-05

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Bohan Li ,  Jingning Han

IPC: H04N19/00 ,  H04N19/139 ,  H04N19/105 ,  H04N19/577 ,  H04N19/573 ,  H04N19/172 ,  H04N19/537

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：US11153588B2

公开(公告)日：2021-10-19

申请号：US16838529

申请日：2020-04-02

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Yaowu Xu

IPC: H04N19/85 ,  H04N19/436 ,  H04N19/176 ,  H04N19/86 ,  H04N19/117 ,  H04N19/14 ,  H04N19/82 ,  H04N19/157 ,  H04N19/122

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：US11025950B2

公开(公告)日：2021-06-01

申请号：US15893978

申请日：2018-02-12

Applicant: GOOGLE LLC

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

IPC: H04N19/00 ,  H04N19/573 ,  H04N19/567 ,  H04N19/70 ,  H04N19/147 ,  H04N19/51 ,  H04N19/577 ,  H04N19/176 ,  H04N19/182 ,  H04N19/44

Abstract: A motion-field based reference frame is rendered that can be used to perform a prediction process for a first frame of a video sequence to be predicted. A first reference frame from the video sequence for forward inter prediction of the first frame is determined, as is a second reference frame from the video sequence for backward inter prediction of the first frame. A respective motion field determined for blocks of the first frame is used to determine parameters forming an affine homographic model. A current block of a reconstructed reference frame is rendered at a co-located position within a motion field-based reference frame by applying the affine homographic model to the current block. An affine homographic model may be determined for each reconstructed reference frame block to render the motion-field based reference frame.

公开(公告)号：US20200382776A1

公开(公告)日：2020-12-03

申请号：US16995078

申请日：2020-08-17

Applicant: Google LLC

Inventor： Yaowu Xu ,  Jingning Han ,  Cheng Chen

IPC: H04N19/117 ,  H04N19/46 ,  H04N19/186 ,  H04N19/176

Abstract: Techniques for encoding and decoding image data are described. An image is reconstructed and deblocked. A respective deblocking filter is identified for different color planes of the image. The deblocking filters may include those having different lengths for a luma plane as compared to one or more chroma planes of the image. One or more of the color planes, such as the luma plane, may have different filters for filtering reconstructed pixels vertically as compared to filtering the reconstructed pixels horizontally.

公开(公告)号：US10820014B2

公开(公告)日：2020-10-27

申请号：US16561165

申请日：2019-09-05

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Yaowu Xu

IPC: H04N19/573 ,  H04N19/52 ,  H04N19/107 ,  H04N19/172 ,  H04N19/176 ,  H04N19/91 ,  H04N19/82 ,  H04N19/86 ,  H04N19/61 ,  H04N19/70 ,  H04N19/126 ,  H04N5/225 ,  H04N19/567 ,  H04N19/577

Abstract: A prediction scheme is selected for encoding or decoding a video block. A first compound motion block can be determined by weighting distances from a first reference frame to the video frame and from a second reference frame to the video frame using one or more quantized weighting coefficients. A second compound motion block can be determined based on an average of pixel values a video block of the first reference frame and pixel values from a video block of the second reference frame. One of the first compound motion block or the second compound motion block is selected and used to generate a prediction block. Alternatively, data encoded to a bitstream including the video frame can be used to determine which compound motion block to use to generate the prediction block. The current block of the video frame is then encoded or decoded using the prediction block.

公开(公告)号：US10701398B2

公开(公告)日：2020-06-30

申请号：US16451415

申请日：2019-06-25

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Ching-Han Chiang

IPC: H04N7/12 ,  H04N19/129 ,  G06T9/00 ,  H04N19/176 ,  H04N19/13 ,  H04N19/60 ,  H04N19/18 ,  H04N19/91 ,  H04N19/134 ,  H04N19/136 ,  H04N19/192

Abstract: Video coding using a context adaptive scan order for entropy coding may include an apparatus decoding a current block by identifying a context adaptive scan order for entropy decoding a transform block, which may include identifying non-zero-coefficient probabilities for the transform block such that each location in the transform block corresponds to a respective non-zero-coefficient probability from the non-zero-coefficient probabilities, assigning a respective context adaptive scan order position to each location in the transform block in descending magnitude order of the respective corresponding non-zero-coefficient probabilities such that the context adaptive scan order position for each location exceeds the context adaptive scan order position assigned to entropy coding context locations for the respective location, entropy decoding transform coefficients from the encoded video stream based on the context adaptive scan order, and reconstructing the decoded block based on the transform block.

公开(公告)号：US20190191164A1

公开(公告)日：2019-06-20

申请号：US15880939

申请日：2018-01-26

Applicant: GOOGLE LLC

Inventor： Jingning Han ,  Dake He

IPC: H04N19/129 ,  H04N19/61 ,  H04N19/18 ,  H04N19/176 ,  H04N19/82

CPC classification number: H04N19/129 ,  H04N19/176 ,  H04N19/18 ,  H04N19/61 ,  H04N19/82

Abstract: A scan order for encoding or decoding coefficients of a transform block is selected on a transform block-level. A set of candidate scan orders is processed by identifying end of block positions within the transform block for each of the candidate scan orders. Cost values are determined for each of the candidate scan orders to reflect a number of the coefficients of the transform block that are located before the respective end of block positions. In particular, a cost value for a candidate scan order reflects the number of zero-value coefficients located before the end of block position for that candidate scan order. One of the candidate scan orders is then selected based on those cost values. The selected scan order is used to scan the coefficients in the transform block, such as for encoding those coefficients to a bitstream or for decoding those coefficients to an output video stream.

公开(公告)号：US10326994B2

公开(公告)日：2019-06-18

申请号：US15950225

申请日：2018-04-11

Applicant: GOOGLE LLC

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

IPC: H04N19/00 ,  H04N19/129 ,  H04N19/159 ,  H04N19/61 ,  H04N19/86 ,  H04N19/13 ,  H04N19/82 ,  H04N19/124

Abstract: A method for coding a transform block of coefficients includes generating a new scan order from the original scan order such that a maximum scan distance of the new scan order is smaller than or equal to a predetermined distance, and coding the coefficients based on the new scan order. An apparatus for decoding a transform block of coefficients. The apparatus includes a memory and a processor. The memory includes instructions executable by the processor to identify an original scan order for encoding the coefficients, generate a new scan order from the original scan order such that a maximum scan distance of the new scan order is less than or equal to a predetermined distance, and decode, from an encoded bitstream, the coefficients based on the new scan order.

公开(公告)号：US20190158843A1

公开(公告)日：2019-05-23

申请号：US15817369

申请日：2017-11-20

Applicant: GOOGLE LLC

Inventor： Yaowu Xu ,  Bohan Li ,  Jingning Han

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

Abstract: An optical flow reference frame portion (e.g., a block or an entire frame) is generated that can be used for inter prediction of blocks of a current frame in a video sequence. A forward reference frame and a backward reference frame are used in an optical flow estimation that produces a respective motion field for pixels of a current frame. The motion fields are used to warp some or all pixels of the reference frames to the pixels of the current frame. The warped reference frame pixels are blended to form the optical flow reference frame portion. The inter prediction may be performed as part of encoding or decoding portions of the current frame.