[FFmpeg-devel] [PATCH 000/279] New channel layout API

[Lynne]

9 Dec 2021, 15:24 by george at nsup.org:

> Anton Khirnov (12021-12-09):
>
>> I see you repeating the same two arguments:
>> - it was implemented like this in the past and therefore must keep
>>  working exactly the same
>> - it might be useful under some vaguely specified conditions
>>
>> Neither of these strikes me as a good enough reason to make major
>> changes to the API design.
>>
>
> I will turn this argument back on you: you have designed your API so
> that it is too limited, it does not strike me as a good reason to make
> major changes in existing filters and devices that have given
> satisfaction to users for years.
>

As a compromise, could we specify that while having multple
channels with the same ID in a single frame can happen and
can be generated by decoders, we would also specify that they
possibly won't be treated correctly by encoders and filters, and
could be outright dropped with a warning if unsupported.

I can see why having multiple channels with the
same ID can happen, an in fact, will, for custom user
layouts with more channels than there are IDs.
For example, an Opus stream containing a hundred or
so channels from multiple overlapping locations from a venue.
Each of those channels would have to have an ID of NONE,
because the codec mapping family doesn't carry such information
for such a configuration.