[MPlayer-users] 6 channel audio, 2 channel card

[Andy Furniss]

Paolo Bolzoni wrote:
> Dear list, I wanted to see a movie with 5.1 audio in my laptop, but
> the dialogues were too low so I wanted to play with volumes with the
> -pan- audio filter.
>
> I downloaded the 6 channel .wav file from (1) and something is
> wrong.
>
>
> If I play it in my desktop system with a 5.1 system it works fine,
> strangely also my 2 channel laptop I hear all the channel a part of
> the subwoofer.
>
>
> Anyhow, to see what is the channel order I tried this:
>
> -af pan=2:0:0:0:0:0:0:0:0:0:0:0:0 , as expected everything is silent
> -af pan=2:1:0:0:0:0:0:0:0:0:0:0:0 , something is strange; I hear
> from the left channel the front left, center, and back left voices.
> As far as I understood I should only hear only one channel from its
> correct speaker. -af pan=2:0:1:0:0:0:0:0:0:0:0:0:0 , same voices as
> before from the right channel. This is expected since the previous
> results, but it is strange.
>
>
> Now, what can possibly happening? Is there some kind of downmix
> before the audio filter? Can I disable that?

If you want boost center do this -

mplayer -channels 6 -af pan=2:0.4:0:0:0.4:0.2:0:0:0.2:0.5:0.5:0.1:0.1

The two 0.5 s are normally 0.3 (so it could in theory clip - probably
not much in practice)

Maybe the wierdness in your tests is because by default mplayer does
downmix (or for ac3/dts actually requests 2 channels from the codec) so
you need -channels 6