Reducing latency in video encoding and decoding

摘要

Techniques and tools for reducing latency in video encoding and decoding by constraining latency due to reordering of video frames, and by indicating the constraint on frame reordering latency with one or more syntax elements that accompany encoded data for the video frames. For example, a real-time communication tool with a video encoder sets a syntax element that indicates a constraint on frame reordering latency, which is consistent with inter-frame dependencies between multiple frames of a video sequence, then outputs the syntax element. A corresponding real-time communication tool with a video decoder receives the syntax element that indicates the constraint on frame reordering latency, determines the constraint on frame reordering latency based on the syntax element, and uses the constraint on frame reordering latency to determine when a reconstructed frame is ready for output (in terms of output order).

主权项

1. In a computing system that implements a video decoder, a method comprising:
receiving and parsing one or more syntax elements that indicate a constraint on frame reordering latency, wherein the constraint on frame reordering latency is expressed in terms of a maximum count of frames that can precede any frame of a video sequence in output order but follow that frame in coded order; determining the constraint on frame reordering latency based upon the one or more syntax elements; receiving encoded data for plural frames of the video sequence; with the video decoder, decoding at least some of the encoded data to reconstruct one of the plural frames; and outputting the reconstructed frame, wherein the constraint is used to determine when the reconstructed frame is ready for output.