[mythtv-users] lossless cut and audio sync drift?

Ian Evans dheianevans at gmail.com
Fri Nov 23 15:29:15 UTC 2012

On Fri, Nov 23, 2012 at 7:37 AM, Doug Vaughan <r.d.vaughan at rogers.com> wrote:
> Ian,
>     I have, but rarely, noticed some audio drift. I am fairly sure, as so
> many of the other issues are, that mkvmerge finds some problem with the
> original recorded mpg file. Here is a reference to mkvmerge parameters that
> you can use from the commandline on an out of sync mkv file post lossless
> cut.
> From: https://www.bunkus.org/videotools/mkvtoolnix/doc/mkvmerge.html
> Some movies start synced correctly but slowly drift out of sync. For these
> kind of movies you can specify a delay factor that is applied to all
> timestamps -- no data is added or removed. So if you make that factor too
> big or too small you'll get bad results. An example is that an episode I
> transcoded was 0.2 seconds out of sync at the end of the movie which was
> 77340 frames long. At 29.97fps 0.2 seconds correspond to approx. 6 frames.
> So I did:
> $ mkvmerge -o goodsync.mkv -y 23456:0,77346/77340 outofsync.mkv
> I hope this helps.
> Doug

thanks for the info, I'll give it a try,

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