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spatialaudio / python-sounddevice

:sound: Play and Record Sound with Python :snake:
https://python-sounddevice.readthedocs.io/
MIT License
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multi processing with sounddevice #245

Open VectorLane opened 4 years ago

VectorLane commented 4 years ago

Hi there,

Newbie, hope this is the correct place to raise issues.

I'm trying to build a program with both input and output using 'sounddevice'. The program outputs into a USB audio interface and reads back the data from it. The process is very heavy so I had separated the incoming data (from USB audio interface) to a different process. Hence - multi processing.

The program uses 'multiprocess queue' between the two processes. For some reason, I couldn’t set the processes to work with the same queue.

What am I doing wrong ?

VectorLane commented 4 years ago

MP_SingleProgram.txt

VectorLane commented 4 years ago

Problem seems to be not relevant to multi processing.

mgeier commented 4 years ago

There have been issues with the multiprocessing module before (#120, #147).

But if it's not related to multiprocessing, can you please provide a minimal example without it?

VectorLane commented 4 years ago

SingleProgramOneProcess_forForum.txt

Yes, here is the working example (single processing).

The problem was that the 'callback' used 'copy by reference' instead of 'copy by value' - so the last audio buffer was always re-written.

In any case, I'm attaching the working and tested example for anyone to use (commercial or private).

The program now generates a sinewave, sends it to the USB audio interface and reads it back. If the audio interface is in "talkback" mode (RME) then one will see the input reflected onto the output.

Setup: Windows 10 PC RME Fireface RME ASIO drivers (as well as testing with ASIO4ALL drivers)