[Jackit-devel] [linux-audio-dev] Re: Multiplexing 4 channels on SPDIF

[Lee Revell]

On Mon, 2006-10-30 at 17:35 +0100, Alfons Adriaensen wrote:
> On Mon, Oct 30, 2006 at 10:07:06AM -0500, Lee Revell wrote:
> 
> > > Some ALSA plugin? Of course, doing it in JACK's ALSA backend is also
> > > reasonably simple, but would require small changes in many places to
> > > override samplerates, etc.
> > 
> > I don't think it even needs to be a plugin, just tell ALSA about the
> > audio format.
> 
> How can you tell ALSA that an SPDIF input is 4 channels ?
> 

The ALSA code would have to be extended... I'm not sure exactly where.

I don't think it should be called SPDIF because SPDIF implies two
channels.

> > Where can the detailed specs be downloaded?
> 
> According to the Core Sound website this thing is still in development,
> and the specs there are incomplete. 
> 
> What they want to do is trick  hardware 2-ch recorders into accepting
> the 4-ch signal. So what is in reality 4 channels at 48 kHz will be
> presented as 2 channels at 96 kHz.
> 

I don't think it's useful to discuss further until technical details are
available.

When specs are available, this thread should probably be re-started on
alsa-devel.

Lee