On 10/21/06, Torgeir Veimo <[EMAIL PROTECTED]> wrote:
> I'm getting bad lipsync with mgatv output, I often see video lagging
> behind the audio by several frames.

I confirm this! I've been struggling with this problem for quite long
time now. I've been thinking if it would be possible to do the syncing
without dropping/doubling video frames by altering the audio playback
somehow. This would perhaps also remove the annoying jerky playback
when switching channels.

Perhaps the optimal solution would be that both of the streams were
synced to the same to one master clock that is kept in sync with the
encoder clock by timestamps from the stream (STC ?) but I don't know
if it is possible in a PC. If I understood correctly, this is what
settopboxes do.

Video stream could in theory be synced by altering video timings
(frame rate?) but how does TV accept this and how could it be done in
practice by software? The audio stream could (again in theory) be
delayed/advanced by altering playback samplerate. But does ALSA allow
this ? If not, how about resampling the audio stream and playing with
a constant sample rate? Another question is if this would make the
audio too noisy.

--
Ari Koponen
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