[MEncoder-users] Audio - Video - Desynchronisation with mencoder

[didiboo at didiboo.de]

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Hello and greetings,


first, my english ist not good, i hope you excuse it.


I want to record MPEG via DVB and recode it to XVID.

The way I do it is:


I catch the MPEG-Stream via dvbstream:

dvbstream -f 11953 -p h -s 27500 -v 110 -a 120 -n 120 -c 0 -o > out.mpeg


Clean it with mencoder:

mencoder -idx -lavdopts er=4 -vc ffmpeg12 -of mpeg -oac copy -ovc copy
out.mpeg -o clean.mpeg


Recode it with mencoder:

mencoder -idx -vf scale=640:-2 -ovc xvid -xvidencopts bitrate=800 -oac
mp3lame -lameopts cbr:br=128 clean.mpeg -o out.avi


This results everytime in a audio-video-desynchronisation. The thing is,
that all the mpeg-streams have got a good audio-video-synch, but the
rsulting avi not. It seems the the audio comes like 100-200 ms too late.

I tried an other way, used szap to select frequency:

szap -r ZDF

and cat to catch the mpeg-stream:

cat /dev/dvb/adapter0/dvr0 > out.mpeg


and then the steps above to encode to avi. The same a/v-desynch problem.
So I believe this problem comes by mencoder.


I compensatet it till now with the use of "-audio-delay -0.17" in the
encoding-step, but this seems a hack for me, and does not result in
really synchronisation.


I would be very happy, if anybody has an idea how to produce avis from
dvb without using vdr and without this audio-video-desynchronisation.



Thank You in advance,

J. Dietrich Boock



Some Informations about the system I use:


- - Linux, Debian unstable, Kernel 2.6.21-2-amd64
- - dvbstream: Version 0.6
- - mencoder: Version dev-SVN-rUNKNOWN-4.1.2

DVB-S-Card, Hauppauge:

dmesg->
cx2388x dvb driver version 0.0.6 loaded
cx8802_register_driver() ->registering driver type=dvb access=shared
CORE cx88[0]: subsystem: 0070:9200, board: Hauppauge Nova-SE2 DVB-S
[card=38]
cx88[0]/2: cx2388x based dvb card
DVB: registering new adapter (cx88[0]).
DVB: registering frontend 0 (Conexant CX24123/CX24109)...
<-

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