[mythtv-users] 30 second skip == stutter

[Doug Larrick]

Jesper Sörensen wrote:

[snip]
> lastaudiotime = 175, buffer->timecode = 80188658
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 177, buffer->timecode = 80188698
> lastaudiotime = 180, buffer->timecode = 80188738
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 181, buffer->timecode = 80188778
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 184, buffer->timecode = 80188818
> lastaudiotime = 186, buffer->timecode = 80188858
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 188, buffer->timecode = 80188898
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 189, buffer->timecode = 80188938
> lastaudiotime = 193, buffer->timecode = 80188978
> 2004-08-21 22:03:36 A/V diverged by -200 frames, dropping frame to keep 
> audio in sync
> lastaudiotime = 194, buffer->timecode = 80189018

The 'lastaudiotime' is supplied by the audio driver. 'buffer->timecode' 
is from the video stream.  The a/v sync code's goal is to keep them as 
close to each other as possible.

As you can see, the audio timestamp is quite a bit smaller than the 
video timestamp.  As playback continues, is there a point where they're 
suddenly much closer to one another?  That's the point where the audio 
driver has finally regained its composure and is sending good data.

I took a brief look at both OSS and ALSA videoout source in Myth, and 
both are supposed to return 0 for the time if they don't know where they 
are.  Figure out why they're not and you'll have this fixed.

I honestly think you (Jesper or John) are better able to debug this than 
I am, since you're seeing the problem and I'm not.  That means (a) you 
have a large supply of test data, and (b) you're motivated to fix it.

-Doug
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 256 bytes
Desc: OpenPGP digital signature
Url : http://mythtv.org/pipermail/mythtv-users/attachments/20040822/98576f4a/signature.pgp