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公开(公告)号:US11140407B2
公开(公告)日:2021-10-05
申请号:US16222254
申请日:2018-12-17
Applicant: Apple Inc.
Inventor: Xiang Fu , Xiaohua Yang , Linfeng Guo , Francesco Iacopino , Felix Chou , Ying Jian He
IPC: H04N19/172 , H04N19/52 , H04N19/176 , H04N19/182 , H04N19/55 , H04N19/167 , H04N19/119
Abstract: Techniques for encoding video with reduced frame-boundary artifacts are presented. The techniques include a video encoding method, where, when skip mode is selected as a motion prediction coding mode for a pixel block predicted from a reference block of a reference frame, estimating an amount of the reference block that extends beyond the edge of the reference frame. If the amount beyond the edge does not exceed a threshold, the prediction may be coded with skip mode. If the amount beyond the edge exceeds a threshold, the pixel block may be partitioned, and the partitioned blocks may be coded with motion prediction.
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公开(公告)号:US10567768B2
公开(公告)日:2020-02-18
申请号:US15487853
申请日:2017-04-14
Applicant: Apple Inc.
Inventor: Xiang Fu , Xiaohua Yang , Linfeng Guo , Francesco Iacopino , Krishna Rapaka , Felix Chou , Mukta Gore
IPC: H04N19/124 , H04L29/06 , H04N19/105 , H04N19/117 , H04N19/176 , H04N19/61 , H04N19/85
Abstract: Techniques are disclosed for developing quantization matrices for use in video coding. According to these techniques a first quantization matrix may be derived from a second quantization matrix by scaling quantization values of the second quantization matrix by scaling parameters. The scaling parameters may increase according to distance between each matrix position and a matrix origin, they may be derived from characteristics of a video sequence to be coded, or both. The first quantization matrix may be communicated to a decoder. Thereafter, a video sequence may be coded predictively. As part of the coding, pixel data of the video sequence may be transformed to a plurality of frequency domain coefficients, and the frequency domain coefficients may be quantized according to the first quantization matrix.
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公开(公告)号:US20200053362A1
公开(公告)日:2020-02-13
申请号:US16100310
申请日:2018-08-10
Applicant: Apple Inc.
Inventor: Xiang Fu , Linfeng Guo , Haiyan He , Wei Li , Xu Gang Zhao , Hao Pan , Xiaohua Yang , Krishnakanth Rapaka , Munehiro Nakazato , Haitao Guo
IPC: H04N19/176 , H04N19/126 , G06N3/08 , G06T7/13
Abstract: Techniques are disclosed for coding image data adaptively at different levels of downscaling. Such techniques may involve partitioning input data into pixel blocks for coding and performing content analysis on the pixel blocks. The pixel blocks may be input to block coders that operate at different pixel block sizes, which may code the pixel blocks input to them at their respective sizes. Except when a block coder operates at the partitioning size, block coders that operate at different pixel block sizes may perform downscaling of the pixel blocks to match their size with the block coders' respective coding size. A block decoder may invert the coding operations performed by the block coders, decoding coded image data at respective pixel block sizes, then upscaling decoded image data obtained therefrom to a common pixel block size. Image reconstruction may synthesize a resultant image from the decode pixel block data output by the decoders. Quality enhancements may be added by neural network processing systems that have been trained to other segmented images.
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公开(公告)号:US20230070492A1
公开(公告)日:2023-03-09
申请号:US17886858
申请日:2022-08-12
Applicant: Apple Inc.
Inventor: Jiancong Luo , Dzung T. Hoang , Francesco Iacopino , Linfeng Guo , Mukta S. Gore , Ryan Baldwin , Supradeep T. Rangarajan , Xiaohua Yang
IPC: H04N19/154 , H04N19/124 , H04N19/18 , H04N19/176
Abstract: Techniques for reducing reduce coding artifacts in video data are disclosed. In one aspect, a frame of video data is partitioned into pixel blocks, which are organized into slices. The pixel blocks of each slice are coded by a compression algorithm and an estimate of coding artifacts in the slice is made. For slices that are estimated to possess coding artifacts, the method revises coding parameters applied to pixel blocks in the slice and recodes the slice. The method substitutes recoded slices for originally-coded slices in frame, working in a priority order from a slice with the highest estimated likelihood of coding artifacts down to slices with lower estimated likelihoods of coding artifacts, measuring changes in the frame's coding size as it goes. The likelihood of coding artifacts can be estimated from slice statistics that may be developed from a comparison of transform coefficients among the pixel blocks within a slice, from an evaluation of transform coefficients of a pixel block with a slice that is estimated to have a lowest spatial complexity, or from coded luma data of the pixel blocks within a slice. In a further aspect, slice statistics may be computed from pixel block data only for a subset of slices within a frame. Slice statistics for other slices may be derived from the statistics of neighboring slices. In another aspect, a method may revise coding parameters in iterative fashion working from an initialized value and estimate (without recoding them) data sizes of coded slices that may be obtained from the revised parameters. As the method operates, it may compare the coding parameters to parameters used in a first iteration of coding and terminate the iterative process for that slice if the first iteration coding parameters are higher than the revised parameter.
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公开(公告)号:US10764588B2
公开(公告)日:2020-09-01
申请号:US16100310
申请日:2018-08-10
Applicant: Apple Inc.
Inventor: Xiang Fu , Linfeng Guo , Haiyan He , Wei Li , Xu Gang Zhao , Hao Pan , Xiaohua Yang , Krishnakanth Rapaka , Munehiro Nakazato , Haitao Guo
IPC: H04N19/176 , H04N19/126 , G06T7/13 , G06N3/08
Abstract: Techniques are disclosed for coding image data adaptively at different levels of downscaling. Such techniques may involve partitioning input data into pixel blocks for coding and performing content analysis on the pixel blocks. The pixel blocks may be input to block coders that operate at different pixel block sizes, which may code the pixel blocks input to them at their respective sizes. Except when a block coder operates at the partitioning size, block coders that operate at different pixel block sizes may perform downscaling of the pixel blocks to match their size with the block coders' respective coding size. A block decoder may invert the coding operations performed by the block coders, decoding coded image data at respective pixel block sizes, then upscaling decoded image data obtained therefrom to a common pixel block size. Image reconstruction may synthesize a resultant image from the decode pixel block data output by the decoders. Quality enhancements may be added by neural network processing systems that have been trained to other segmented images.
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公开(公告)号:US11871052B1
公开(公告)日:2024-01-09
申请号:US16580184
申请日:2019-09-24
Applicant: Apple Inc.
Inventor: Hao Pan , Haitao Guo , Ke Chen , Francesco Iacopino , Jim C. Chou , Xiaohua Yang , Linfeng Guo , Munehiro Nakazato , Krishnakanth Rapaka , Ye Cong
IPC: G06F15/16 , H04N21/2343 , G02B27/00 , G06T19/00 , H04N21/2662
CPC classification number: H04N21/2343 , G02B27/0093 , G06T19/006 , H04N21/2662
Abstract: In one implementation, a method of generating a bit stream encoding a video stream is performed by a device including one or more processors and non-transitory memory. The method includes decomposing a video stream into a plurality of frequency band video streams. The method includes determining a target bitrate and determining, for each frequency band video stream, a respective frequency band bit rate based on the target bit rate. The method includes encoding each of the plurality of frequency band video streams at its respective frequency band bit rate and transmitting, over a channel, each encoded frequency band video stream.
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公开(公告)号:US20180352240A1
公开(公告)日:2018-12-06
申请号:US15613172
申请日:2017-06-03
Applicant: Apple Inc.
Inventor: Krishnakanth Rapaka , Mukta Gore , Sunder Venkateswaran , Xiaohua Yang , Xiang Fu , Francesco Iacopino , Linfeng Guo
IPC: H04N19/187 , H04N19/51 , H04N19/31 , H04N19/39
Abstract: Techniques for encoding video with temporal layering are described, comprising predicting a sequence of pictures with a motion prediction reference pattern having a number of virtual temporal layers, and encoding the sequence of pictures into an encoded bitstream with a temporal layering syntax, wherein a number of signaled temporal layers is less than the number of virtual temporal layers. The number of signaled temporal layers may be determined from a target highest frame rate, a target base layer frame rate, and the number of virtual temporal layers.
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公开(公告)号:US20180302621A1
公开(公告)日:2018-10-18
申请号:US15487853
申请日:2017-04-14
Applicant: Apple Inc.
Inventor: Xiang Fu , Xiaohua Yang , Linfeng Guo , Francesco Iacopino , Krishna Rapaka , Felix Chou , Mukta Gore
IPC: H04N19/124 , H04L29/06 , H04N19/105 , H04N19/117 , H04N19/176 , H04N19/61 , H04N19/85
CPC classification number: H04N19/124 , H04L65/4069 , H04L65/602 , H04L65/607 , H04N19/105 , H04N19/117 , H04N19/126 , H04N19/136 , H04N19/154 , H04N19/176 , H04N19/463 , H04N19/61 , H04N19/85
Abstract: Techniques are disclosed for developing quantization matrices for use in video coding. According to these techniques a first quantization matrix may be derived from a second quantization matrix by scaling quantization values of the second quantization matrix by scaling parameters. The scaling parameters may increase according to distance between each matrix position and a matrix origin, they may be derived from characteristics of a video sequence to be coded, or both. The first quantization matrix may be communicated to a decoder. Thereafter, a video sequence may be coded predictively. As part of the coding, pixel data of the video sequence may be transformed to a plurality of frequency domain coefficients, and the frequency domain coefficients may be quantized according to the first quantization matrix.
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