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

jon bird news at onastick.clara.co.uk
Mon Mar 9 20:47:16 CET 2009

In article <20090308154616.7ce5f041.cooleyr at gmail.com>, RC 
<cooleyr at gmail.com> writes
>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.
bad cut and paste on my part there...

>No attempt taken to avoid skipped frames completely corrupting the
ok, well I'm sure I got that from an example somewhere off the web - if 
it's all bad then what is the 'good' way of doing it? I'm after 
something playable in most OTS players so not the raw stream (that you'd 
get by just doing a 'cp').

>> 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.
true, I didn't. In the wealth of options available to both packages I'd 
really like a steer on what is needed then.



== jon bird - software engineer
== <reply to address _may_ be invalid, real mail below>
== <reduce rsi, stop using the shift key>
== posted as: news 'at' onastick 'dot' clara.co.uk

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