[MPlayer-users] Decoding AC3 to multiple soundcards ?

[Stephen Davies]

On 4 Feb 2002, Steffen Neumann wrote:

> 
> Hi,
> 
> I would like to avoid bying 
> an expensive 5.1 soundcard.
> 
> Instead I'd like the ac3 signal to be decoded 
> and two of the 5 sent to an onboard soundchip,
> and the remaining 3 to a cheap 4 channel card.
> Alsa is in place for both cards.
> 
> Is that feasible ? Would Latency between cards
> be a problem ? If not:
> 
> How to do this ? Would it need a new 
> sound filter plugin ?
> 

Hi,

I think that you will have some difficulties with syncronising the two
sound cards.  They will have different fragment sizes and so forth.

But I'd like to see someone have a go and see how well it works in
practice.

I'd suggest that you start with a "quick and dirty" proof of concept -
perhaps a new ao2 output driver that opens both dsp devices and splits the
audio to both.  You will probably need some buffering in the driver.

The audio plugin system doesn't currently allow for a plugin to drive two
sound drivers - so you can't easily implement as a plugin - perhaps Anders
can comment on extending the plugin architecture to "split" the stream.

Steve