[MPlayer-users] video desynchronisation artefact

Vladimir Komendantsky komendantsky at gmail.com
Fri Feb 18 18:14:10 CET 2011


Hi there,

Can anyone help me to understand why I'm getting a very strange "no frame
per second" phenomenon when I encode mpeg2 videos copied from dvds with the
following profile data:

[dvdcopy]
ovc=copy=yes
oac=copy=yes
of=mpeg=yes
mpegopts=format=dvd:tsaf=yes
noskip=yes
mc=0

The profiles for the 2-pass mpeg4 encoding are as follows:

[dvd-mpeg4-pass1]
ffourcc=DX50
ovc=lavc=yes
oac=copy=yes
lavcopts=vcodec=mpeg4:autoaspect=yes:mbd=2:vbitrate=2025:trell=yes:v4mv=yes:turbo=yes:vpass=1:vqcomp=0.55
nosub=yes
alang=en
noskip=yes
mc=0

[dvd-mpeg4-pass2]
profile=dvd-mpeg4-pass1
lavcopts=turbo=no:vpass=2

When MPlayer plays back the resulting AVI file, audio and video are
completely out of sync with audio played at the original speed while video
streams extremely fast, apparently with no frame-per-second correspondence.
Only "-mc 0" helps to synchronise playback.

And this is given that mplayer is aware of the correct FPS, for example:

VIDEO:  [DX50]  720x480  24bpp  29.970 fps  2062.7 kbps (251.8 kbyte/s)

This feature appears as standard when I first copy a DVD and then encode the
copy with lavc. It does not appear if xvid encoder is used instead. But lavc
is much better for my purposes than xvid.

I want the encoded file be normal, so that mplayer should not require "-mc
0" to play it correctly. How would you encode it?

Many thanks,
Vladimir


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