[FFmpeg-trac] #4698(avcodec:closed): Wrong channel layout for FLAC 3/1 channels on playback

FFmpeg trac at avcodec.org
Mon Jul 20 10:30:06 CEST 2015

#4698: Wrong channel layout for FLAC 3/1 channels on playback
             Reporter:  Mango        |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:  avcodec
              Version:  unspecified  |               Resolution:  invalid
             Keywords:  flac         |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |

Comment (by Mango):

 Replying to [comment:24 cehoyos]:
 > Replying to [comment:23 Mango]:
 > > ffmpeg version 2.7 Copyright (c) 2000-2015 the FFmpeg developers
 > Please test current FFmpeg git head unless you want to report a
 regression or a security issue that is not reproducible with current
 > > For out.flac, mediainfo reports the correct channel positions (which
 means ffmpeg has set the WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag correctly):
 > So there is no bug? I will close the ticket, if there still is an issue,
 please explain how I can reproduce with current FFmpeg.
 > Or does {{{ffmpeg -i out.flac}}} show an incorrect channel layout?

 Like ffplay and ffprobe, {{{ffmpeg -i out.flac}}} fails to show the
 {{{WAVEFORMATEXTENSIBLE_CHANNEL_MASK: 0x107}}} which was written by ffmpeg
 (and ffmpeg based players wrongly play is as 2/2 instead of 3/1 channels):

     ENCODER         : Lavf56.36.100
   Duration: 00:00:12.32, start: 0.000000, bitrate: 2740 kb/s
     Stream #0:0: Audio: flac, 48000 Hz, 4.0, s32 (24 bit)

 But the tag IS there, as mediainfo shows and LAV plays it correctly with
 the 3/1 channel layout.

 And as said above:

 ffmpeg playback is the problem (2/2 channels instead of 3/1) + the red
 error on encoding

 '''The only purpose of this red error seems to be to inform that ffmpeg
 will play it back with a wrong channel mapping.''' Other tools (i.ex LAV,
 mediainfo), show the right channel mapping with this ffmpeg encoded flac).

Ticket URL: <https://trac.ffmpeg.org/ticket/4698#comment:26>
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