Adaptive quantization for enhancement layer video coding

摘要

Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels.

主权项

1. A computing device including a processor and memory, wherein the computing device implements a video encoder adapted to perform operations comprising:
encoding video for a picture organized in multiple color channels, including:
varying quantization spatially and between the multiple color channels of the video for the picture; andfor a current unit of the video for the picture, predicting a unit-level quantization parameter (“QP”) for the current unit using multiple unit-level QPs for spatially neighboring units; and outputting the encoded video for the picture in a bitstream, including:
signaling QP information in the bitstream that indicates multiple QPs that at least in part parameterize the varied quantization of the video for the picture, the QP information including the unit-level QP for the current unit signaled as a differential QP relative to the predicted unit-level QP for the current unit.