Recording multiple audio in a session messes up my COM, am I doing something wrong?

[ahmadharis4u]

I have used miniaudio to handle/insert & play audio in my application.
When I record multiple audio in the same session (5 times, to be precise), it messes up COM registration and my application stops doing a key COM based action.
I am using below variables for recording and doing init & uninit of device for each recording.
// Recording params
ma_device_config m_deviceConfig;
ma_device m_device;
drwav m_wav;
The complete code of my miniAudioPlayer sample app can be found here:
https://github.com/ahmadharis4u/MiniAudio-Player/blob/master/MiniAudioPlayer/AudioEngine.cpp

Recording itself works fine, but don't know how to fix the COM corruption issue.
PS: I suspect double COM deregister within the audio lib, or maybe something wrong in the way I coded the Record process.

Any leads would be appreciated.

[mackron]

I don't have an exact answer for you. But I can see you've initialized an engine with ma_engine_init(), but I can't see an ma_engine_uninit(). Maybe look at that?

miniaudio will initialize and uninitialize COM in two places - one is whenever a ma_context is initialized and uninitialized and the other is in the worker thread. You can see them in ma_worker_thread() and ma_context_init_backend_apis__win32() / ma_context_uninit_backend_apis__win32(). There's no bugs with the way miniaudio is doing it from what I can tell. If you need to customize the value that's passed into CoInitializeEx() you can do so by overriding MA_COINIT_VALUE:

#define MA_COINIT_VALUE 0 // <-- Set this to your desired value.
#define MINIAUDIO_IMPLEMENTATION
#include <miniaudio.h>

[mackron]

Also, just a minor thing with your code which is not related to your COM problem - you don't need to persistently hold the ma_device_config object. Once ma_device_init() has returned the device config is no longer used and can be discarded. You would normally declare the device config on the stack.

[ahmadharis4u]

Setting below solved the issue.
#define MA_COINIT_VALUE COINIT_APARTMENTTHREADED

But I am afraid if that will affect other COM functions of my app (if it uses COINIT value 0 elsewhere).
Should COINIT value be same app wide ? or it can be different based on thread usage?

Also, the engine uninit is missing in my sample app, but I have it in my actual app and verified that as well.

[mackron]

The whole COM situation is stupid and really confusing. I'm not 100% sure on the rules, but the documentation says this (https://docs.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-coinitializeex):

Multiple calls to CoInitializeEx by the same thread are allowed as long as they pass the same concurrency flag

So I guess all calls on the same thread must match, but across different threads it can be different?

[ahmadharis4u]

Thank you for the explanation.
Appreciate the effort.