[FFmpeg-devel] [PATCH] ALSA: implement channel layout for playback.

Carl Eugen Hoyos cehoyos
Mon Mar 14 12:13:29 CET 2011

Nicolas George <nicolas.george <at> normalesup.org> writes:

> > More difficult is to fix AV_CH_LAYOUT_4POINT0
> > (Edward.Scissorhands.x264.DTS-4.0-48_24.mkv), because it has to be mapped to
> > 5.1 - Alsa's 4-channel layout is AV_CH_LAYOUT_QUAD.
> My opinion is that the output driver should not do that automatically. Using
> an audio filter: "-af layout=5.1", would IMHO be a better solution.

I don't disagree, but if 4 channel output was requested, it should either set
surround to silence or map the back channel to both surround channels. What
should be done with centre in this case?

Carl Eugen

More information about the ffmpeg-devel mailing list