[MPlayer-users] AC3 stream reordered on encode

[Rich Felker]

On Sat, Oct 22, 2005 at 11:13:03AM +0930, n0dalus wrote:
> On 10/22/05, Giacomo Comes <comes at naic.edu> wrote:
> > To be more accurate what you have is:
> >
> > 0 front left
> > 1 rear left
> > 2 rear right
> > 3 centre
> > 4 front right
> > 5 lfe
> >
> > Probably nobody has noticed the bug because nobody will
> > reencode an ac3 5.1 stream to an ac3 5.1 stream with libavcodec.
> >
> > > Is there something I can do to fix this? I can't hear the difference
> >
> > add -af channels=6:6:0:0:4:1:1:2:2:3:3:4:5:5 to you command line.
> >
> > Giacomo
> >
> 
> Thankyou that seems to have worked.
> Do you think that someone will be able to write a patch for this bug?
> 
> Is there anything wrong with re-encoding ac3? I am doing it here
> because I am changing framerate (to PAL) and -oac copy doesn't work.

Are you changing framerate with -speed? This is the best way, but if
you change it with -ofps (frame duplication) you can use -oac copy.
The tradeoff is that video will look choppy. On the other hand, audio
pitch will me increased with -speed, so neither way is perfect.

Another solution that would work with -oac copy would be a
2:2:2:2:2:2:2:2:2:2:2:3 pulldown mode in the mpeg muxer, but that's
not implemented yet.

Rich