[FFmpeg-user] AVC / AAC 2 passes , Incomplete MB-tree stats file. message

Carl Eugen Hoyos cehoyos at ag.or.at
Mon Jan 21 23:57:08 CET 2013

jacky <renaux.jacky <at> orange.fr> writes:

> Le 21/01/2013 16:35, Carl Eugen Hoyos a écrit :
> > jacky <renaux.jacky <at> orange.fr> writes:
> >
> >> set lcmda1=    -an
> >> set lcmda2=    -acodec libvo_aacenc -ab 48k -ar 22050 -ac 1
> >
> > Does it also fail if you use the same options for lcmda1 as
> > for lcmda2 ?
> it does not fail if I use lcmda2 for pass 1 and pass 2

I absolutely may miss something, but to keep A/V-sync, it is not 
unusual to drop or duplicate frames (it is actually the default 
behaviour). This of course never happens with -an (no audio, no 
A/V sync to take care of). So depending on your input sample 
(and the chosen output container), -pass 1 -an vs -pass 2 
-acodec ... may lead to a different number of frames and that 
definitely hurts the rate-control badly.

Carl Eugen

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