Question: Volume control?

Sjoerd82 commented 6 years ago

This probably demonstrates my lack of understanding on the inner workings of JACK, but here it goes... Why doesn't come jackclient with any volume controls? This is my No.1 Python need for Jack ;-) Thanks for clarifying.

MaurizioB commented 6 years ago

Because that's not how jack works. Audio streams are treated as they are received from the source client, it's up to the source or the receiver to eventually process the sound stream.

If you need volume controls, use a dedicated client (such as jack_mixer) and connect it according to your needs. It is technically possible to control the gain of a stream connected to a owned jack client, but since python is not very reliable for real time audio processing, I'd advise against that.

Il mer 11 apr 2018 13:57 Sjoerd82 notifications@github.com ha scritto:

This probably demonstrates my lack of understanding on the inner workings of JACK, but here it goes... Why doesn't come jackclient with any volume controls? This is my No.1 Python need for Jack ;-) Thanks for clarifying.

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Sjoerd82 commented 6 years ago

Ok, thanks for clarifying :+1:

mgeier commented 6 years ago

@Sjoerd82 In what way do you want to change the volume?

There are multiple ways to do this, but not all of them might make sense in your case.

simply multiply each sample with a weighting factor (very easy if you use NumPy)
use a separate JACK client to change the volume, as @MaurizioB suggested (BTW, the URL http://home.gna.org/jackmixer seems to be broken ATM)
try to change the volume of a certain channel in the audio backend (e.g. ALSA, CoreAudio)

@MaurizioB:

It is technically possible to control the gain of a stream connected to a owned jack client

Are you talking about multiplying each sample with a given factor? If not, what are you talking about?

spatialaudio / jackclient-python

Question: Volume control? #49