公开(公告)号：US20230362387A1

公开(公告)日：2023-11-09

申请号：US18296351

申请日：2023-04-05

Applicant: Apple Inc.

Inventor： Felix C. Fernandes

IPC: H04N19/147 ,  H04N19/176 ,  H04N19/124

CPC classification number: H04N19/147 ,  H04N19/176 ,  H04N19/124

Abstract: Block-based, low latency rate control for an encoding system in which a wavelet transform decomposes pixel blocks into subbands stored as subbands in wavelet blocks (WBs) for encoding. Quantization parameters (QPs) for the subbands in each WB are estimated using a method that minimizes wavelet-inverse distortion given a rate bound. For each subband, a rate curve is generated based on an unquantized DCT histogram and bit count statistics for the subband, and a distortion curve is generated based on the unquantized DCT histogram and a distortion estimate for the subband that is estimated using a masked estimator. Once the rate-distortion curves for the subbands are generated, a bisection search may be used to find a point on each curve where the slope is the same for all the curves. The QPs associated with those equally sloped points are the global minimizing QPs for the wavelet block.

公开(公告)号：US20230085391A1

公开(公告)日：2023-03-16

申请号：US17591572

申请日：2022-02-02

Applicant: Apple Inc.

Inventor： Felix C. Fernandes ,  Liviu R. Morogan

IPC: H04N19/117 ,  H04N19/82 ,  H04N19/132 ,  H04N19/86 ,  H04N19/186 ,  G06T5/40

Abstract: Systems and methods of analyzing the luma statistics or chroma statistics to correct for image artifacts in decoded images. Video decoder circuitry may enable luma statistics collection circuitry housed in the loop filters to collect luma samples during the last stage of the decoding process. This enables output of luma statistics data and output of the decoded image together.

公开(公告)号：US20230009707A1

公开(公告)日：2023-01-12

申请号：US17933057

申请日：2022-09-16

Applicant: Apple Inc.

Inventor： Hao Pan ,  Jim C. Chou ,  Felix C. Fernandes

IPC: H04N19/146 ,  H04N19/14 ,  H04N19/176 ,  H04N19/169 ,  H04N19/63 ,  H04L65/70 ,  H04L65/75

Abstract: A video encoding system in which pixel data is decomposed into frequency bands prior to encoding. The frequency bands for a slice of a frame may be buffered so that complexity statistics may be calculated across the frequency bands prior to encoding. The statistics may then be used by a rate control component in determining quantization parameters for the frequency bands for modulating the rate in the encoder for the current slice. The quantization parameters for the frequency bands may be calculated jointly to optimize the quality of the displayed frames after decoder reconstruction and wavelet synthesis on a receiving device. Information about one or more previously processed frames may be used in combination with the statistics for a current slice in determining the quantization parameters for the current slice.