[pulseaudio-discuss] Gap, silence and latency

James Lee csejl at yahoo.com
Fri Mar 16 10:34:40 PDT 2012

Tanu Kaskinen <tanuk <at> iki.fi> writes:

> On Thu, 2012-03-15 at 21:43 +0000, James Lee wrote:
> > Tanu Kaskinen <tanuk <at> iki.fi> writes:
> > > Regardless of any delays due to the underruns, Pulseaudio will report
> > > the current latency to the client, and that latency information should
> > > be used to synchronize the video playback with audio. If things get
> > > permanently out-of-sync, then either the video player isn't using this
> > > information properly, or the alsa driver is acting funny, leading to
> > > incorrect latency information.
> > 
> > Any other thoughts on this?  If there's any other info I can provide, please 
> > me know.  Thanks.
> Well, how do you do the a-v sync? Do you actively monitor the audio
> latency, or do you check it only at the beginning of the stream, or do
> you ignore it altogether?

A/V sync is handled in the decoders based on the current PCR and PTS values for 
each audio/video frame.  Our concern is audio latency through pulse, not A/V 
synchronization.  The latency jumps right after the gap.

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