Synchronization method of audio/video frames of set top box

Abstract

The invention provides a synchronization method of audio / video frames of a set top box, which comprises the steps of: firstly, receiving the audio / video frames, analyzing display time labels and program clock references of the audio / video frames before decoding; secondly, computing the maximum play time of the audio / video frames in a whole buffer area according to the buffer capacity and the size of the audio / video frames in the buffer area; thirdly, computing the average decoding time of the audio / video frames and comparing the display time labels with a system clock according to the average decoding time, obtaining the compared difference of the display time labels and the system clock before decoding; and fourthly, comparing the compared difference before decoding, the average decoding time and the maximum play time to dynamically and self-adaptively select corresponding synchronization conditions.

Description

technical field [0001] The invention relates to a method for synchronizing audio and video frames of a set-top box, in particular to an adaptive method for synchronizing audio and video frames of a set-top box. Background technique [0002] Today's set-top box (Set Top Box, STB) needs to perform synchronous operation according to the display time stamp (Presentation Time Stamp, PTS) of the audio and video frame and refer to the program clock reference (ProgramClock Reference, PCR) when playing digital TV programs, so that Sound and video can be played normally. [0003] See Figure 1A ~ 1C , Figure 1A ~ 1C Respectively depict the time correspondence between the audio and video frames received by the set-top box system and their display time labels AU, VI and the program clock reference PCR. Under normal circumstances, the program clock reference PCR will be as Figure 1A The display time labels AU and VI of the audio and video frames slightly ahead of the time shown in , ...

AI Technical Summary

Problems solved by technology

In some programs, the clock reference PCR is ahead of the display time labels AU and VI of the audio and video frames for a very short time. If the synchronization conditions are set too strictly, after the audio and video frames AU and VI are decoded, it is easy to cause outdated frame drop phenomenon.

Additionally, if Figure 1B As shown in , the program clock reference PCR of some code streams is ahead of the display time stamps of audio and video frames AU and VI for a long time, which may cause insufficient buffer capacity for storing audio and video frames and make it difficult to synchronize

or, as in Figure 1C As shown in , the display time labels AU and VI of the audio and video frames of some code streams are simply behind the program clock reference PCR, which makes the synchronization impossible

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