Set latency for a plugin generated with faust (faust2juce)

Audio Plugins
1

Hi all,
I wrote an audio plugin in faust. It has a defined latency because of a lookahead function.
As the faust2juce architecture has no option to report latency to the projucer, my question is: Where and how can I set the latency which the plugin reports back to the DAW?
Thanks!

2

You should use the method AudioProcessor::setLatencySamples().

3

Thanks. Where in the projucer code would I put that?

4

And is there a way to make this dependent on the samplerate?
My lookahead in faust is defined as 0.001 seconds.

5

There is no way to do it from the projucer, you’ll have to code it in the prepareToPlay() or processBlock() methods. You should have a look at the example DSPModuleDemoPlugin.

6

thank you, will try

7

Just a note that from my experience, putting setLatencySamples() in processBlock() is not handled well by a number of Windows hosts, resulting in audio artifacts. PrepareToPlay() is a safe place to do it.

8

And this is not well supported by Cubase on macOS either :wink: Indeed, it seems that prepareToPlay() is the best place to do it.

9

@trummerschlunk We could possibly code that at Faust DSP level using a syntax like:

  • declare options [latency_frames:<frames>] or declare options [latency_sec:<sec>]

  • the have the C++ architecture uses this metadata with AudioProcessor::setLatencySamples() in prepareToPlay() .

Would this work?

10

That would be awesome :slightly_smiling_face:
latency_samples would also be great.

11

Done in [NEW] Latency metadata added in faust2juce. Set version to 2.48.4. · grame-cncm/faust@a8dd82e · GitHub
and read faust/architecture/juce at master-dev · grame-cncm/faust · GitHub