[FFmpeg-devel] [PATCH 1/5] avutil/channel_layout: add 22.2 layout

Carl Eugen Hoyos ceffmpeg at gmail.com
Sat Aug 1 16:04:13 EEST 2020

Am Sa., 1. Aug. 2020 um 14:47 Uhr schrieb Jan Ekström <jeebjp at gmail.com>:
> On Sat, Aug 1, 2020 at 3:08 PM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> >
> > Am Sa., 1. Aug. 2020 um 14:06 Uhr schrieb Jan Ekström <jeebjp at gmail.com>:
> >
> > > Additionally, the spec only mentions stereo/5.1 for direct mapping, so
> > > I've kept to 5.1 since we have the capability for that one.
> >
> > And you still believe it would be a disadvantage if the decoder outputs
> > this 5.1 mapping by default if nothing else was requested?
> Yes. API users so far have received the audio frames according to
> encoded layout by default, so doing something else breaks that rule of
> least surprises.
> > Is there an option to request the 5.1 mapping?
> As noted in the 0/0 cover letter, you can do it just fine with
> `-channel_layout "5.1"` with ffmpeg.c. I have verified that it returns
> the 5.1 channels as-is.

But this does not make the decoder output 5.1 or does it?

While I should probably only care about ffmpeg and ignore
the library users I still wonder who can live with your approach...

> At this point I would not like to attempt to figure out how to skip
> channel coding units in the AAC decoder

Just throw them away?

Thank you for your effort, Carl Eugen

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