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1. 发明授权

US5828414A Reduction of timing jitter in audio-video transport streams 失效
标题翻译：降低音视频传输流中的定时抖动
公开(公告)号：US5828414A
公开(公告)日：1998-10-27
申请号：US606197
申请日：1996-02-23
申请人： Michael G. Perkins , Thomas Lookabaugh
发明人： Michael G. Perkins , Thomas Lookabaugh
IPC分类号： H04N21/43 , H04N21/434 , H04N21/643 , H04N7/12
CPC分类号： H04N21/4305 , H04N21/4344 , H04N21/64307
摘要： A method and apparatus for reducing program clock reference (PCR) jitter in transport packets of a transport stream compliant with MPEG-2 or another suitable audio-video encoding standard. The PCRs from a given single program transport stream (SPTS) of a multi-program transport stream are processed in a phase-locked loop (PLL) to generate dejittered PCRs for that SPTS. The PLL for a given SPTS receives as inputs the PCRs from that SPTS and a cycle count for each PCR indicative of the number of asynchronous clock cycles counted since the previous PCR. The PLL generates a given dejittered PCR as a function of the previous dejittered PCR, the cycle count for the given PCR, and a clock frequency mismatch estimate for the given program clock. The clock frequency mismatch estimate is generated by filtering a sequence of jitter estimates, each corresponding to the difference between a previous PCR and its corresponding dejittered PCR. The SPTS transport packets may then be restamped with the dejittered PCRs from the PLL to provide a dejittered multi-program transport stream.
摘要翻译：一种用于减少符合MPEG-2或其他合适的音频 - 视频编码标准的传输流的传输分组中的节目时钟参考（PCR）抖动的方法和装置。来自多节目传输流的给定单个节目传输流（SPTS）的PCR在锁相环（PLL）中被处理，以产生针对该SPTS的解聚PCR。给定SPTS的PLL接收来自该SPTS的PCR作为输入，并且每个PCR的循环计数指示自先前PCR以来计数的异步时钟周期的数量。 PLL产生给定的去抖动PCR作为先前的去极化PCR的函数，给定PCR的循环计数以及给定程序时钟的时钟频率失配估计。时钟频率失配估计是通过对抖动估计序列进行滤波而产生的，每个抖动估计对应于先前的PCR与其对应的去极化PCR之间的差异。然后可以使用来自PLL的去抖动PCR来修复SPTS传输分组，以提供解复用的多节目传输流。

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