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Do soc support snd_pcm_rewind() and snd_pcm_forward ?

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No driver demand yet, though it'd be trivially implemented if anyone wanted to do it.

if size of fifo is around 1x ~ 3x fames

How accucate do those media player need to allow A/V lip sync , Video is about 24 ~ 30 frames per seconds and audio is 48000Hz ?