Apple Inc.

Felix C Fernandes

Jim Chen Chou

Hao Pan

Sorin Constantin Cismas

Jeffrey J Irwin

Yaxiong Zhou

Liviu R Morogan

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.

Rate control for low latency video encoding and transmission

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.

Block-based low latency rate control

Systems and methods of parallel image parsing and processing for video decoding are provided. Video decoder circuitry may enable an incoming encoded bitstream to be split into multiple bitstreams corresponding to the bitstream compression scheme and processed by multiple parsers corresponding to the bitstream compression scheme in parallel. This enables parallel decoding of the incoming bitstream and, thus, more efficient decoder processing.

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Saratoga, CA, United States of America

Felix C Fernandes