[FFmpeg-user] inconsistent ffmpeg results when running same command on different machines

[Anatol]

The same ffmpeg/Linux binary running on different hardwares or different
Linux version might produce different output files.
We had this with MPEG-TS decoding - there was bug in ffmpeg 0.10, it used
multi-threaded decoding as a default. Some machines handled it properly,
while others had nasty artifacts. It had to do with type of hw acceleration
that each machine had and the drivers that it used.


On Mon, Aug 12, 2013 at 1:57 AM, Frank Schwieterman <fschwiet at gmail.com>wrote:

>   Thanks for the insight Moritz.  I suspect that the libx264 version is
> determined by whoever puts together the build, and so picking up windows
> and mac builds there isn't a straightforward way to keep those in sync.
>  Getting a binary match is not critical, so this is ok.
>   One concern though is that the result lengths are different.  I am trying
> to extract a clip of a specific length, which is going to be concatenated
> for a loop effect.  It is important that the concatenated portion is a
> specific time duration because the loop establishes a musical tempo.
>   The command I run should extract video from time 0.1 to 0.2, so I'd
> expect the output result to be 0.1 seconds long.  From the output, it says
> it is 0.11s or 0.12s instead (I see "frame= 3 fps=0.0 q=-1.0 Lsize= 133kB
> time=00:00:00.12 bitrate=8851.7kbits/s dup=6 drop=0" in one). I suppose
> 0.02 error on the duration is reasonable, if the error stays the same as
> the clip is extended. Would you know if I could expect a similar fixed-size
> error regardless of the duration of the extracted clip?
>
> On Sun, Aug 11, 2013 at 3:04 PM, Moritz Barsnick <barsnick at gmx.net> wrote:
>
> > On Sun, Aug 11, 2013 at 14:51:49 -0700, Frank Schwieterman wrote:
> > > I suspect the ffmpeg configuration is different...
> >
> > The ffmpeg output (at the very top) will hint you towards that.
> >
> > > Is it possible to configure things such that I'd get the same result
> > > from both machines?
> >
> > I guess if the identical versions of ffmpeg and all used libraries are
> > identical (same versions, same configuration, not necessarily same
> > compilers though), it should work.
> >
> > Your ffmpeg base code seems in sync (judging from the reported versions
> > of the libav* libraries).
> >
> > But since these two differ version-wise:
> > > [libx264 @ 0x7ff461908e00] 264 - core 125 - H.264/MPEG-4 AVC codec -
> > Copyleft 2003-2012 - http://www.videolan.org/x264.html - options:
> cabac=1
> > ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1
> psy_rd=1.00:0.00
> > mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0
> deadzone=21,11
> > fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1
> > sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0
> > constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1
> > weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40
> > intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60
> qpmin=0
> > qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
> > > [libx264 @ 0000000002246da0] 264 - core 130 r2274 c832fe9 -
> H.264/MPEG-4
> > AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html -
> > options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7
> psy=1
> > psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1
> > cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6
> > lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
> > bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
> > b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
> > scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
> > qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
> > you can suspect that they won't create bitwise identical output in the
> > payload.
> >
> > Moritz
> > _______________________________________________
> > ffmpeg-user mailing list
> > ffmpeg-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>