[mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues

Andrew Gallatin gallatin at cs.duke.edu
Fri Dec 11 15:54:36 UTC 2009


Byron Poland [wpoland at gmail.com] wrote:
> for the past couple of months anything I record from WPVI in Philadelphia
> (delivered via clear qam from Verizon FIOS in Wilmington, DE), has had
> playback problems where the video and audio fall out of sync, and myth then
> speeds up the video and/or drops frames for a second or 2 to catch up.  I've
> read the list and seen other threads describing a similar phenomenon,
> including being isolated to one channel.  All other 720p and 1080 recordings

<..>

I think this is the same problem as reported here, nearly
2 years ago:
  http://www.gossamer-threads.com/lists/mythtv/dev/317736

As DanielK said "they are just using an encoding extension we don't
support very well.....I believe they are broadcasting about 40 fps on
a 60fps stream and marking some of the frames as repeatable"
If this is true, you may have luck complaining to the broadcaster like
the people in that thread did.  Unfortunately, that's not much of an
option for me, as multiple broadcasters in my market have their
encoders setup this way.  The only way I was able to play back these
sorts of streams was by using a non-MythTV front end (sigma based
SageTV HD100).

I'd love to come back to MythTV, and I'm eagerly looking forward to a
fix to this.  I have a mythbox setup running trunk, and I'm happy to
test patches, make snippets of these streams available to the devs,
etc.

Drew


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