[MPlayer-dev-eng] Re: [PATCH] channel reordering for 6ch audio

[Frank Aurich]

Alexander 'Lazy Ranma' Ponyatikh wrote:
> Mplayer's support for 6 ch sound is crappy. The only thing that works
> correctly is AC3 audio (at least with -ao dsound). Every codec
> produces or requests channels in its own order, and mplayer almost
> never reorders them. As result channels are often mixed up.
> 
> I made some research on channel ordering of various codecs and
> drivers, and made some patches to make them correctly reorder channels
> to/from mplayer default order. I took L R SL SR C LFE sequence as
> mplayer default, since it's used by ad_liba52.c, af_hrtf.c,
> ao_dsound.c.
> 
> ao_dsound.c
> Native order:   L R C  LFE SL SR (windows default)
> Expected input: L R SL SR  C LFE (mplayer default)
> Driver correctly reorders channels
> 
> ao_pcm.c
> Native order: L R C LFE SL SR (windows default)
> Expected input: native
> Reordering required
> 
> ad_faad.c
> Native order: C L R  SL SR LFE
> Output order: native
> Reordering required
> 
> ad_liba52.c
> Native order: L R SL SR C LFE converted from planar LFE L C R SL SR
> (using MMX)
> Output order: L R SL SR C LFE (mplayer default)
> Codec correctly reoders channels
> 
> ad_libvorbis.c
> Native order: unknown
> Output order: native
> I didn't find any standards for Vorbis, b/c many codecs differently
> reorder channels. Even files encoded/decoded by the same tools got
> their channel order completely mixed up.
> 
> ad_pcm.c
> Native order: L R C LFE SL SR (windows default)
> Output order: native
> Reordering required
> 
> ae_lavc.c
> Native order: L C R  SL SR LFE
> Expected input: native
> Reordering required
> 
> ae_pcm.c
> Native order: L R C LFE SL SR (windows default)
> Output order: native
> Reordering required
> 
> 
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Corey Hickey addressed the problem of wrong channel order in AAC/faad audio a 
while ago:

http://thread.gmane.org/gmane.comp.video.mplayer.devel/32141/focus=32141

I've been using this patch since then, and it works as expected. I can't say 
which one of the patches is better, you decide.


Frank