Opened 6 years ago

Closed 6 years ago

#6 closed defect (fixed)

Alsa output channel order is wrong

Reported by: cehoyos Owned by: michael
Priority: normal Component: avformat
Version: git Keywords:
Cc: Blocked By:
Blocking: Reproduced by developer: yes
Analyzed by developer: yes

Description

http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/129213
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.

Change History (1)

comment:1 Changed 6 years ago by cehoyos

  • Resolution set to fixed
  • Status changed from new to closed

This is fixed now for 5.1 and 7.1 audio.

I believe it would make sense for four and five channel audio to automatically select six channel alsa output and map the channels accordingly. This has not been implemented yet.

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