[linux-audio-dev] Multiplexing 4 channels on SPDIF

[Fons Adriaensen]

Hello all,

Core Sound <http://www.core-sound.com/default.php> willsoon
be offering a tetrahedral (Ambisonic) microphone at a very
reasonable price. They are also working on a combined preamp
+ AD converter unit for this mic. This will be able to multiplex
the 4 channels over a single SPDIF link, by using it a the
double sample frequency.

I'm currently working on a software controller unit for this
microphone. It will perform A-format to B-format conversion,
and allow measured impulse responses to be used for calibrating
the four mics. The result should be a very high quality portable
surround recording system at a reasonable price (compared to other
solutions which cost easily five times as much).

The remaining problem is the demultiplexing of the two double
speed SPDIF channels to four channels. It could either be done
within the ALSA layer, or in JACK's ALSA backend. Doing this
in a JACK client will not work unless it would be the only
client - all others would get the wrong idea of the sample
frequency and buffer size. 

So here's my question to both the ALSA and JACK teams: what
would be your idea of a solution for this ?

-- 
FA

Lascia la spina, cogli la rosa.