[MEncoder-users] Audio Sync issues

[Jeff Cranmer]

On Fri, 2011-09-16 at 15:53 -0500, Rolf Ernst wrote:
> On Fri, Sep 16, 2011 at 1:45 PM, Jeff Cranmer <jeff at lotussevencars.com>wrote:
> 
> > -mc 0 didn't seem to help.
> > Perhaps I'm misunderstanding this, but wouldn't we want to set the
> > number to something else other than 0, to allow the program to A-V sync
> > sucessfully?
> >
> > On Fri, 2011-09-16 at 09:35 -0400, Jeff Cranmer wrote:
> > > > About the -noskip option:  maximum A-V sync correction per frame (in
> > > > seconds) -mc 0 should always be combined with -noskip for mencoder,
> > > > otherwise it will almost certainly cause A-V desync.  I don't know if
> > > > that will help.  All you can do is try it.
> > > >
> > > > Bill
> >
> > Jeff,
> 
> what he says is correct - normally you want to set it to 0 which means
> 'don't deviate at all from the a/v sync'. That being said - I have never
> used it with the PVR encodes, not sure whether it would be of benefit or
> detriment - I just don't have any sync issues. I will give it a try using
> -oac pcm and see whether this might play into it.
> 
> Part of the problem could be that I don't think pcm has timecodes built into
> it, just x number of samples/sec whereas if you copy the AC3 stream that has
> timecodes. This becomes important as there are occasional 'glitches' in the
> recordings that the PVR makes. It's really of no big importance as the
> playback can always recover because of the timecodes for both the audio and
> video stream. (Look months back in this list and you will see how I brought
> it up before). Since the pcm does not carry timecode information the
> occasional glitch might throw it off, just a hypothesis. Just for grins I
> would suggest to do an -oac copy and see whether this solves the problem. At
> least you will know where to look then.

So far, I've had no luck with -oac copy, as I get an error when I try
it.  The audio stream appears to be AAC rather than AC3.  Does this
change anything?  
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