[FFmpeg-trac] #5718(avcodec:open): ffmpeg not remapping channels for libopus automatically

FFmpeg trac at avcodec.org
Sun Jul 17 02:52:24 EEST 2016

#5718: ffmpeg not remapping channels for libopus automatically
             Reporter:  agressiv     |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  important    |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  libopus      |               Blocked By:
  regression                         |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |

Comment (by mgraczyk):

 When I wrote this patch, I did not realize that channel_layouts was used
 to automatically remix the channel layout from 5.1(side) to 5.1. I did not
 intend to change default behavior with that patch.

 However, my understanding was that the error here is potentially
 desirable.  The ogg audio stream in output.mkv has a different channel
 layout than the audio in the input file.

 I see that in most cases remapping 5.1(side) to 5.1 is the right thing to
 do. Is there any way to get this automatic remapping only when the
 mapping_family parameter is not provided?

 Also, what do you mean by "Command-line opusenc automatically remaps as
 well"? How do you process mkv files with opusenc? Are you sure the process
 used to extract audio from the mkv file didn't do the remapping?

Ticket URL: <https://trac.ffmpeg.org/ticket/5718#comment:5>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker

More information about the FFmpeg-trac mailing list