[MEncoder-users] a/v sync issues transcoding UK DVB-T

RC cooleyr at gmail.com
Sun Mar 8 23:46:16 CET 2009

On Sun, 8 Mar 2009 19:31:11 +0000
jon bird <news at onastick.clara.co.uk> wrote:

> Here's what I doing to record the stream:
> mencoder -ovc copy -oac copy -of mpeg -endpos -o somefile.avi
> dvb://somechannel

Nothing but bad ideas all around:

Demuxing and remuxing, for no reason.

Creating an MPEG-2 file named .avi

Using -endpos is not going to be clock-accurate.

No attempt taken to avoid skipped frames completely corrupting the


> or in some instances to DVD:
> mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf -vf
> scale=720:576,harddup -lavcopts
> vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=2500:ke
> yint =15:vstrict=0:acodec=mp2:abitrate=192:aspect=16/9 -ofps 25   -o
> test.avi infile.avi

Just about guaranteed A/V sync issues if you use -oac lavc.  Besides,
twolame sounds much better.

> I also tried similar transcoding direct with ffmpeg and this also
> exhibits a similar problem which makes me think its something in the
> source (recorded) format

It makes _me_ think you didn't use the -copyts option.

Don't trust me! I'm wrong!

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