高清晰度电视芯片中视频和音频同步的异步实现

高清晰度电视的传输流采用了MPEG－2系统层标准ISO／IEC 13818－1。阐述了高清晰度电视（HDTV）传送流中时间信息码在视频和音频同步中的作用，分析了信源解码器中视频和音频同步的原理。就实际芯片中系统时钟的恢复，视频和音频的跳帧等机制进行了讨论，并提出了一种非锁相异步全数字视音同步实现方案。该方案采用了直接置数法恢复系统时钟,滞后跳帧法实现视频与系统时钟的同步，数字锁相法控制音频与系统时钟同步，最后，对视频帧率和音频PCM时钟的偏差等问题作了进一步的探讨。

Asynchronous implementation of synchronizing the video and audio in HDTV decoder

The format of transport stream of high definition television(HDTV) is defined in MPEG\|2 system standard ISO/IEC 13818\|1.The function of timing information code on synchronizing the video and audio is explained in this paper,and the principle of synchronization of video and audio in HDTV decoder is analyzed.The problems in practical ASIC design, such as the mechanisms of rebuilding of system clock and repeating frame or skipping frame in video and audio, are discussed, a simple non\|PLL digital scheme of synchronizing the video and audio is also provided. Update now the method of rebuilding system clock, lagged skipping frame method of synchronization of video and system clock, and digital PLL method of synchronization of audio and system clock are adopted in this scheme. The frame rate of video and warp of audio PCM clock frequency are discussed at last.