Mencoder a/v Sync Problem + Transcode Tutorial ? [Solved]

le_barbu · #1 09-12-2006, 01:40 AM

hi, I use mencoder 1.08pre (and Mandriva 2006) to backup a DVD, but I have audio desynchronisation while playing my KSVCD (at the beginning the audio is sync). Here's my command line:

Code:

mencoder dvd://1 -aid 129 -ovc lavc -oac lavc -lavcopts acodec=mp2:abitrate=224:vcodec=mpeg2video:trell:keyint=24:vstrict=-1:vrc_eq=(tex/avgTex+1)^0.5:vmax_b_frames=2:dia=2:dc=8:mbd=2:vrc_buf_size=917:vbitrate=1000:vrc_maxrate=2520:mv0:psnr:inter_matrix=$kvcd_matrix:intra_matrix=$kvcd_matrix -srate 44100 -af lavcresample=44100,volnorm=1 -vf scale=352:432,expand=352:576,harddup,hqdn3d=2:1:2,pp=hb/vb/dr/al/lb -of mpeg -mpegopts vaspect=4/3:format=xsvcd -fps 25000/1000 -ofps 25 -o movie.mpeg

And does someone have a transcode tutorial since I've read the manpage but... it's so complicated!

thx.

Dialhot · #2 09-12-2006, 02:54 AM

Mencoder is considered as not reliable so we frozen the forum where we were speaking about it. Moreover we do not use to encode audio at the same time as video, so it's not sure that you would have an answer.

As a workarround you should encode video first, then see if length in minutes of the encoded video matches the length au the source. Then encode the audio with something else (besweetGUI for instance) and see if all has the same length. Else I guess that you have a framerate issue somewhere (is the source PAL or NTSC ?).

About transcode, I don't know it, can you give a link to it ?

le_barbu · #3 09-12-2006, 05:09 AM

[Edit]

The problem came from the "lavc" audio codec !
I was encoding my video with the lavc codec for the video and the audio streams...

So, I've tried with: lavc for the video stream and twolame for the audio one: It worked !

I have no more synchronisation problem !!!!!!!!!!!!!!!!!!!

PS: the "twolame" codec is present in the Linux/Unix version of mplayer but (by default) is not present in the windows one.
So Linux Users: Let's go enccoding !!!!!!!!!!!!!!!!

[/Edit]

Ok, I'll try to encode Audio and Video separately...

for transcode, here's the url: http://www.transcoding.org/cgi-bin/transcode
it is another unix "swiss knife" video tool, and it's often used for converting videos... like in the "tovid" scripts.

thx.

PS: for the framerate issue, I don't think: my video source is 25fps (I think because it is PAL) and my target video is 25fps PAL

Dialhot · #4 09-12-2006, 06:20 AM

Great. People often look for unix/linux tool to handle their video