Sets the display name of the Flutter app in Windows' mixer. Solves the issue of the name not changing in the mixer without setting the user agent (DartVLC).

set_display_name.dart

import 'dart:ffi';

import 'package:ffi/ffi.dart';
import 'package:win32/win32.dart';

/// Documentation:
/// Dart Win32 Example - https://github.com/timsneath/win32/blob/main/example/wasapi.dart
/// 
/// Win32Api IMMDeviceEnumerator - https://docs.microsoft.com/en-us/windows/win32/api/mmdeviceapi/nn-mmdeviceapi-immdeviceenumerator
/// 
/// Win32Api IMMDevice - https://docs.microsoft.com/en-us/windows/win32/api/mmdeviceapi/nn-mmdeviceapi-immdevice
/// 
/// Win32Api IAudioClient - https://docs.microsoft.com/en-us/windows/win32/api/audioclient/nn-audioclient-iaudioclient
/// 
/// Win32Api IAudioSessionControl - https://docs.microsoft.com/en-us/windows/win32/api/audiopolicy/nn-audiopolicy-iaudiosessioncontrol
///
/// This is done with win32 v2.6.1
void setDisplayName(String name) {
    // Get the default audio device.
    Pointer<COMObject> ptrIMMDE = COMObject.createFromID(CLSID_MMDeviceEnumerator, IID_IMMDeviceEnumerator);
    IMMDeviceEnumerator immde = IMMDeviceEnumerator(ptrIMMDE);
    Pointer<Pointer<COMObject>> ptrIMMD = calloc<Pointer<COMObject>>();
    immde.GetDefaultAudioEndpoint(0, 0, ptrIMMD);

    // Active an IAudioClient for the output device.
    IMMDevice immd = IMMDevice(ptrIMMD.cast());
    Pointer<Pointer<COMObject>> ptrIAC = calloc<Pointer<COMObject>>();
    Pointer<GUID> ptrIACGuid = convertToIID(IID_IAudioClient);
    immd.Activate(ptrIACGuid, CLSCTX_ALL, nullptr, ptrIAC);

    // Initialize IAudioClient and get the IAudioSessionControl service.
    IAudioClient iac = IAudioClient(ptrIAC.cast());
    Pointer<Pointer<WAVEFORMATEX>> ptrMixFormat = calloc<Pointer<WAVEFORMATEX>>();

    iac.GetMixFormat(ptrMixFormat);
    iac.Initialize(0, 0, 30000, 0, ptrMixFormat.value, nullptr);

    Pointer<Pointer<COMObject>> ptrIASC = calloc<Pointer<COMObject>>();
    Pointer<GUID> ptrIASCGuid = convertToIID(IID_IAudioSessionControl);
    iac.GetService(ptrIASCGuid, ptrIASC);

    // Set the display name.
    IAudioSessionControl iasc = IAudioSessionControl(ptrIASC.cast());
    iasc.SetDisplayName(name.toNativeUtf16(), nullptr);

    // Release resources.
    calloc.free(ptrIMMDE);
    calloc.free(ptrIMMD);
    calloc.free(ptrIAC);
    calloc.free(ptrIACGuid);
    calloc.free(ptrMixFormat);
    calloc.free(ptrIASC);
    calloc.free(ptrIASCGuid);

    immde.Release();
    immd.Release();
    iac.Release();
    iasc.Release();
}