Fixed buffer size but with a loopback device?

[ghost]

Hello,
I am trying to use the example here: https://github.com/mackron/miniaudio/blob/master/examples/fixed_size_callback.c but amend it so that it reads from a loopback device, not a sine wave. I tried replacing the global ring_buffer without success. Is there such an example?

Thanks.

[mackron]

Moved this to the Discussions section.

I don't know what you're trying to achieve. Are you wanting to capture data from a loopback device and then output that to a different playback device? If so, you'll need to use a completely different approach to the fixed_size_callback example. If on the other hand you just want to replace ma_device_type_playback with ma_device_type_loopback, you'll need to swap the direction of the data flow. In both cases, no, there's no example.

[ghost]

Thank you so much for the reply and for the wonderful library. Let me explain. I need to accumulate 4096 samples from either a microphone or a loop-back device, and only then process the buffer to an output device (loudspeakers / writing a wav file to disk).

I am not sure which of the above-named scenarios fits.

[mackron]

OK, it sounds like you want a duplex device. Use the simple_duplex example as a basis instead: https://github.com/mackron/miniaudio/blob/master/examples/simple_duplex.c

A duplex device takes input from a microphone which allows you to output that to a playback device. Doing processing in chunks of 4096 will make things complicated due to needing to keep everything in sync. It should be possible, but it's a non-trivial problem which you'll need to spend time figuring out on your own (not even miniaudio's duplex system handles syncing properly yet).

As a start, I would suggest taking that simple_duplex example I mentioned above and plug in the WAV encoding logic from the simple_capture example for outputting to a wav file.

[mackron]

Further to this, after implementing the WAV encoding logic I would suggest adapting the fixed_size_buffer example to suit your purposes for fixed sized processing. I'm not sure off the top of my head how you'd implement it for both reading and writing.