[MPlayer-users] Mencoder big noise

[Reimar Döffinger]

On Tue, May 20, 2014 at 09:57:58AM +0200, Manuel wrote:
> Hi,
> I'm trying to encode a file, using mencoder:
> 
> ./mencoder Frag-Los.400.Dual.1920x820p.H264.AC3.mkv -o v-3782.avi -ovc x264
> -x264encopts \
> qcomp=0.7:subq=6:partitions=all:8x8dct:me=umh:frameref=5:bframes=3:b_pyramid=normal:weight_b
> -vf scale=1280:546 \
> -aid 2 -oac mp3lame -lameopts preset=standard
> 
> And the result is that v-3782.avi hasa loud noise instead of sound.
> 
> I have tried the same with AC3 with the same results:
> 
> ./mencoder Frag-Los.400.Dual.1920x820p.H264.AC3.mkv -o v-3782.avi -ovc x264
> -x264encopts \
> qcomp=0.7:subq=6:partitions=all:8x8dct:me=umh:frameref=5:bframes=3:b_pyramid=normal:weight_b
> -vf scale=1280:546 \
> -aid 2 -oac lavc -lavcopts acodec=ac3:abitrate=224
> 
> The same problem arises with other mkv files.

This is in many ways rather a limitation/missing feature in MEncoder than
a bug: MEncoder cannot handle when the format of the audio stream
changes in any way.
I made it print a warning for that case.
However what (I guess) is a bug for this specific file is that it
doesn't detect the format correctly initially when it seems it could.
I think I fixed that.

> The problem does not appear (IT WORKS OK) with mencoder svn r34540 (Ubuntu),
> lame 3.99.3, libx264-120.2151

"Work" in the meaning of "it just happens to work because FFmpeg just
happens to decode to the format MEncoder thought it would by chance".
So I think the only thing that changed is which format FFmpeg decodes to
by default.