[mythtv-users] A/V delay when recording HD

[Florin Andrei]

I stumbled upon this post on doom9:

http://forum.doom9.org/showthread.php?t=125966&page=326#6517

eac3to is a Windows tool to demux A and V tracks from an HD file.
The OP is correct, as far as I was able to verify - demuxing HD records 
made by my MythTV 0.21 server from Comcast cable in NorCal, using HDHR, 
does exhibit the same pattern: there's a 1000ms or more sync difference 
between A and V tracks.

Now, the files are played correctly by MythTV - when displaying the 
recording, there's no A/V desync. Also, eac3to seems to extract the 
tracks correctly - when remuxed, they stay in sync (but a chunk of video 
is lost, presumably by eac3to when demuxing to fix the A/V timing 
difference).

Therefore there appears to be no problem, but the OP is right - this is 
mystifying. Where does the timing difference come from? Is that how HD 
is being broadcast, or is it due to some buffering or something 
performed by MythTV, or is that how HDHR sends the A/V streams?

I don't know if the OP uses an HDHR, or whether that matters at all. I'm 
just puzzled by the situation.

-- 
Florin Andrei

http://florin.myip.org/