[Ardour-Users] Web Audio API with Ardour

Chris Caudle 6807.chris at pop.powweb.com
Wed Dec 29 09:51:52 PST 2021

On Wed, December 29, 2021 10:09 am, Johnny NC wrote:
> I have written a live lightshow driven by the music I'm playing.
> I'd like to be able to record with Ardour and flow the music through to
> my web page https://johnnywunder.info/SmokingOnThePorch/liveTheMusic.html
> but with Ardour up it never flows. I'm using Ubuntu Studio with Jack
> with a Mackie Onyx USB Producer.
> I'm relatively new to Ardour either recording or the lightshow work fine
> separately. I've played with many setting but can't see to get Ardour
> to stop exclusively grabbing the audio.
> Is it possible and if so what do I need to change?

Are you actually using the JACK backend in Ardour, or the ALSA backend?
If you are using the ALSA backend, Ardour will grab exclusive use of the
audio hardware, there is no way around that, you will need to use jackd. 
Rather, you will need to use an audio server, the three currently suitable
being jackd 1, which works well but it not really maintained these days,
or jackd 2, latest version is 1.9.19, or Pipewire, which implements
several audio and video APIs including JACK.
Probably Ubuntu Studio has jackd 2, and that will be the best way for you
to do what you need.
You can start jackd from the command line, but often people use a GUI
application like QJackControl or Catia to configure jackd.  I do not know
which Ubuntu Studio provides, perhaps someone who uses Ubuntu regularly
could help out with that.

Using the JACK backend, then jackd has exclusive control of the audio
hardware, and you need to setup connections from the audio source to both
Ardour track input and the lightshow software input.  That is where using
the GUI configuration tools are most convenient, you will need to draw
connections from system_in ports (assuming you are playing music live) to
both the lightshow  software inputs and the Ardour track inputs you want
to use for recording.

You did not mention which software you are using for the lightshow
control. Hopefully it supports the JACK API already, otherwise you will
have to bridge from jackd to whatever API the software supports. 
Presumably ALSA, but all the software I use is natively JACK aware, so I
am not sure of the procedures to do that.  Someone on the list may be able
to advise once you have given more details about the lightshow software

Chris Caudle

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