[Libav-user] 7.1 audio in aac codec

[Carl Eugen Hoyos]

Am Sa., 10. Aug. 2019 um 02:07 Uhr schrieb Gonzalo Garramuño
<ggarra13 at gmail.com>:
>
>
> El 9/8/19 a las 17:33, Gonzalo Garramuño escribió:
> >
> > El 9/8/19 a las 17:05, Carl Eugen Hoyos escribió:
> >> Am Fr., 9. Aug. 2019 um 21:41 Uhr schrieb Gonzalo Garramuño
> >> <ggarra13 at gmail.com>:
> >>> I am trying to encode 7.1 audio in an aac codec in my program, but the
> >>> codec only supports up to 6 channels and I get an error to that effect
> >>> if I try to force it to use AV_CH_LAYOUT_7POINT1.
> >> Please provide sample code, 7.1 is supposed to work fine with the
> >> native aac encoder.
> >>
> >> Carl Eugen
> > Never mind me.  I was saving with the ac3 encoder.  Sorry for the noise.
> >
> Well, I was able to save aac 7.1 audio.  However, upon playback I get an
> information message that says:
>
> Assuming an incorrectly encoded 7.1 channel layout instead of a
> spec-compliant 7.1(wide) layout, use -strict 1 to decode according to
> the specification instead.

This is correct.

> I use:
>
> avctx->std_strict_compliance = FF_COMPLIANCE_STRICT;
>
> and it removes one of the info messages, but not all.

> Anyway, it would be better if the messages were not produced at all.

Why do you think so?

> I tried saving with a channel layout of AV_CH_LAYOUT_7POINT1_SIDE
> but it resulted in noise upon reproduction.

Probably because your input is not 7.1(wide).

Carl Eugen