Re: [LAU] Multiple asynchronous JACK chains resampled?

> What I want to do, is to use the resources I have to run multiple
> signal generation and processing chains asynchronously, in
> parallel, and then use the final audio-hardware-synchronized chain
> to resample them all into one, perhaps using the Zita tools.
> Anyone know if this is possible? I saw this flow structure work
> very well in the video domain, quite a few years ago.
>
>
> That's not what you want to do at all.
>
> JACK is designed to be a *synchronous* system. All clients process
> audio corresponding to the same period of time, precisely in sync with
> each other. You do not want to "resample them all into one", and
> certainly not with the zita tools.
>
> A "correct" digital audio processing and/or synthesis environment
> consists of a single audio interface (or at least, a single digital
> sample ("word") clock). You can run any number of JACK clients,
> connected in arbitrary ways. But using multiple audio interfaces
> (which is what the zita tools are related to) is not the right thing
> to do unless you are forced to by lack of funds or inappropriate hardware.
>

I do understand that JACK is designed to be completely synchronous. But
a good pipelined architecture, can take multiple synchronous processing
chains running independently (asynchronously to each other), and then
merge them at the output end. What I want to do is the equivalent using
JACK at the synchronous level, so that I take advantage of more of my
computing power. Eventually I will want to do exactly the same using
four or five RPi-compatibles, with just one of them having the audio
output; but right now I have about 75% of my CPU and 6+ gigabytes of RAM
not being touched, so clearly the testbed is waiting :-). The video
processing pipeline I saw a while ago used a proprietary bus (it was a
while ago), I am thinking IP is probably the simplest now, over
localhost within this box, and through a good switch whenever I start
work on RPis (which is probably not soon but is worth contemplating).

And to use the Zita tools, I was going to see if there was an
audio-over-IP transport which delivered ALSA ports :-) I don't quite
remember, it has been about eight months since I looked. If there is, I
would expect the existing Zita tools would do wonderfully for the
resampling connectors. If not, I wonder what best to use for
JACK-to-JACK resampling?

-- 
Jonathan E. Brickman   jeb@email-addr-hidden   (785)233-9977
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Received on Tue Feb 23 20:15:02 2016