[MPlayer-users] more 4speaker questions

[Stephen Davies]

On 7 Oct 2002, gabor wrote:

> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> hi,
> 
> so i'm playing with my sb-live + 4speakersm, oss, alsa9 etc.
> 
> 1.
> when i'm playing an ac3(5.1) movie, ac3 5.1 means that it contains 6
> (5?) mono audio channels. correct?
> 
> and when specifying -channels_4 those 6 channels get correctly downmixed
> to 4, or just 2 channels get ignored?

channels 4 will mix centre to left and right front, equally, and drop the
LFE channel, IIRC.

> 2.
> i'm trying to use the sp/dif on my sb-live ( -afm hwac3 ) ( with no
> success for now :-) ....
> so let's assume it would work...
> now that means that i send the ac3 data directly to the card. correct?
> but now how does the card know if he should create 6channels or
> 4channels? ( maybe this is not mplayer's problem, but maybe someone can
> answer this )

The card doesn't do anything except push the ac3 stream out of the spdif
port.  Your external AC3 decoder will decode it.

Steve