RECOVERING FROM DISCONTINUITIES IN TIME SYNCHRONIZATION IN AUDIO/VIDEO DECODER

摘要

A decoder for decoding compressed video and audio data. The demultiplexer provides a prediction of a presentation timestamp (PTS) after a discontinuity occurs that is conditional on whether data of the elementary bit stream is still present in the demultiplexer and control decoder module when the discontinuity is detected. If data is still present, the prediction is based on extrapolation from a PTS received prior to the discontinuity using a duration of sample data in the elementary bit stream. If data is no longer present in the demultiplexer, the prediction is based on the current time indicated by the local clock extrapolated using a defined latency.

主权项

1. A decoder for decoding a packetized elementary bit stream containing compressed audio and video data and a series of presentation timestamps (PTS) for synchronizing presentation of the audio and video, the decoder comprising:
a demultiplexer and control decoder module for retrieving elementary bit streams from the packetized elementary bit stream; a local clock; and a presentation decoder module that decodes the retrieved elementary bit streams for presentation, wherein, if the last PTS in data from the elementary bit stream is valid when a discontinuity occurs in the series of PTS, the demultiplexer and control decoder module provides a prediction of a PTS after the discontinuity that is based on extrapolation from a PTS received prior to detection of the discontinuity using a defined duration of sample data in the elementary bit stream, and if the last PTS in data from the elementary bit stream has lapsed when the discontinuity is detected, the prediction of the PTS after detection of the discontinuity is based on the current time indicated by the local clock extrapolated using a defined duration.