Alsa output channel order is wrong
|Reported by:||Carl Eugen Hoyos||Owned by:||Michael Niedermayer|
|Blocking:||Reproduced by developer:||yes|
|Analyzed by developer:||yes|
When using ffmpeg -i input -f alsa, the channel order is typically wrong for >2 channels.
Alsa expects 5.1 in the order: front left - front right - surround left - surround right - centre - lfe, FFmpeg's internal channel order is front left - front right - centre - lfe - surround left - surround right (for 7.1, back channels are last in both cases).
The order is correct for AV_CH_LAYOUT_QUAD, for AV_CH_LAYOUT_4POINT0 (Edward.Scissorhands.x264.DTS-4.0-48_24.mkv), it would be necessary to expand output to (at least) five channels.