[FFmpeg-user] ProRes422 with 8 audio tracks converted to mp4 -- muffles audio 4

[Harvey Pikelberger]

> On Nov 21, 2018, at 9:25 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 
> 2018-11-21 18:18 GMT+01:00, Harvey Pikelberger <communque at gmail.com>:
> 
>> RE "The audio configuration of your two input is very different..."
>> Is the issue that the ProRes is encoded 7.1 -- or -- that it's not 7.1
>> but FFmpeg is interpreting as such?
> 
> I missed "Guessed Channel Layout for Input Stream #0.1 : 7.1" and
> after looking at the file, the channel layout is not supported by FFmpeg.
> 
> Not sure if it really would make a difference if the layout were
> recognized, you would still have to use the split filter because
> the channel layout couldn't be written and writing it will not be
> trivial imo.
> 

Does this imply there's something particular about the test files that makes the audio layout unrecognizable to FFmpeg
or Is there something about ProRes files in general that makes the audio layout unrecognizable?