[FFmpeg-devel] [PATCH] avfilter/af_pan: ignore named channels not in current layout

[Marton Balint]

On Wed, 10 May 2017, Ricardo Constantino wrote:

> instead of erroring out.
>
> af pan=stereo|FL=FL|FR=FR|FC=FC would error because there's no
> Front Center in stereo layout.
>
> This allows just changing the output channel layout and keeping
> the same channel configuration across more than one output.
>
> Example usecase
> * changing balance to the right-side channels for stereo and 7.1
>
> before:
> pan=stereo|FL=0.2*FL+0.8*FR|FR=0*FL+1*FR
> pan=7.1|FL=0.2*FL+0.8*FR|FR=0.0*FL+1.0*FR|FC=FC|LFE=LFE|BL=0.2*BL+0.8*BR|BR=0.0*BL+1.0*BR|SL=0.2*SL+0.8*SR|SR=0.0*SL+1.0*SR
>
> after:
> pan=stereo|FL=0.2*FL+0.8*FR|FR=0.0*FL+1.0*FR|FC=FC|LFE=LFE|BL=0.2*BL+0.8*BR|BR=0.0*BL+1.0*BR|SL=0.2*SL+0.8*SR|SR=0.0*SL+1.0*SR
> pan=7.1|FL=0.2*FL+0.8*FR|FR=0.0*FL+1.0*FR|FC=FC|LFE=LFE|BL=0.2*BL+0.8*BR|BR=0.0*BL+1.0*BR|SL=0.2*SL+0.8*SR|SR=0.0*SL+1.0*SR

You still have to use a different command line for stereo and 7.1, so I 
don't quite see how this simplifies your use case. Even if your use case 
were justified, I'd still think the current behaviour should be preserved 
as a default.

Regards,
Marton