Bug 6.1 Opus Audio Channel Mapping?
#1
I have a movie with a 6.1 opus audio track.  During playback it sounds like the channel mapping is incorrect (dialog is in rear right channel, etc)

When I press o to get the "Player Process Information OSD" it says the channel maps are:

     Audio stream: FL, FR, FC, LFE, BC, SL, SR, ff-opus 32 bits, 48,000 Hz

But when I check the opus spec, its says the channelmap should be:

      7 channels: 6.1 surround (front left, front center, front right, side left, side right, rear center, LFE).

https://datatracker.ietf.org/doc/html/rf...on-5.1.1.2

When I play a 6.1 dtsma audio track the channels sound correct, and the reported channel mapping is the same order.

Is kodi using the correct channel mapping for 6.1 opus audio?

I am using version 20.2.0 on linux.

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#2
Found the problem.  It is with ffmpeg's opus encoder, not kodi's playback.

Evidently ffmpeg has a bug that gets the channel map wrong for 6.1.   But there is a work around, add "-mapping_family 1" like so:

   -c:a:0  libopus -b:a:0 700k -mapping_family 1

Reportedly that causes ffmpeg to use a newer api to talk to the libopus library.  It sounds like it is safe to add that regardless of the number of channels too.
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6.1 Opus Audio Channel Mapping?0