How to downmix 5.1 and 7.1 channels to 2 channels

[Amanda Ava Koci Pereira]

Thanks for the tip!

Em qua., 21 de out. de 2020 às 10:57, Ricard Wanderlof <ricardw at axis.com>
escreveu:

>
> On Tue, 20 Oct 2020, Amanda Ava Koci Pereira wrote:
>
> > Hi guys...
> >
> > We need some clues about to downmix 5.1 and 7.1 channels to 2 channels
> >
> > for the moment we are using the following code ->
> >
> > It works but fails miserably if all channels have data at same time
> >
>
> Is the problem that you get clipping if there is audio on more than one
> input channel?
>
> In general, if you sum a number (N)( of digital channels which have a
> maximum amplitude of M, then the maximum amplitude of the sum will be N *
> M. So in this case you need to reduce the output amplitude by 1/N if you
> want to keep the maximum amplitude of the sum at M.
>
> So in your case you need to set
>
> > #define AR_K_P_ATTENUATION_LEVEL 1.0
>
> according to the number of channels being downmixed per output channel.
>
> /Ricard
> --
> Ricard Wolf Wanderlof                           ricardw(at)axis.com
> Axis Communications AB, Lund, Sweden            www.axis.com
> Phone +46 46 272 2016                           Fax +46 46 13 61 30
>