C# How to programatically change the playback device

Question

How can I programatically change the default audio device on a vista / win 7 system? Using C# or a Win API call?

Pages

This is basically a duplicate of #1334576 except input vs output device, either way, there is no API for it on Vista+ unless you want to decompile media center and find the undocumented stuff – Annotate

Answer 1

The WinMM API should provide the functionality that you request.

You would use the DRVM_MAPPER_PREFERRED_SET message, which is sent with waveOutMessage() function.

Documentation: http://msdn.microsoft.com/en-us/library/aa909789.aspx

However, if you are trying to send the waveform sound out yourself, you should look at the WinMM.Net library.

http://winmm.codeplex.com

Quan

All I need to do is change the sound device on Windows, so that all audio routes through that device. Essentially I have a lot of sound devices on my system, and I want to replace the default sys tray app, so that I don't need to right click , open the device manager each time I need to switch a device. Will this API do this? – Pages

Yes, You can set the default audio playback device in XP with the DRVM_MAPPER_PREFERRED_SET message, which is sent with waveOutMessage(). This doesn't work in Vista. I am researching. – Quan

Thanks, I think this last link will work, it should port to win 7 hopefully! – Pages

Love that last link! It's been driving nuts in Win7 having to launch the Playback devices dialog every time I want to switch from headphones to speakers, and vice-versa. Much easier now. Thanks! – Repute

@Repute how exactly did you do that ? WinMM.net doesn't seem to have waveOutMessage functionality. In fact native library import for waveOutMessage is surrounded with #if false preprocessor directive. – Landonlandor

Jonathan Sampson removed the link to vistaaudiochanger.com because it's inactive. That sucks. I didn't play with WinMM.net. – Repute

In fact DRVM_MAPPER_PREFERRED_SET doesn't work even on XP, it returns MMSYSERR_INVALPARAM. And documentation that you linked to clearly states it's for Windows Mobile. – Diophantus

Answer 2

I found the AudioSwitcher constructor to be extra slow in my case.

I suggest using the "CoreAudio" API for managing audio devices.

Here is a current wrapper library available on NuGet. https://github.com/morphx666/CoreAudio/tree/master

Set device:

public static void SetDefaultDevice(string id) {
    MMDeviceEnumerator deviceEnum = new MMDeviceEnumerator(Guid.NewGuid());
    MMDevice device = deviceEnum.GetDevice(id);
    deviceEnum.SetDefaultAudioEndpoint(device);
}

Get devices

public static MMDeviceCollection GetAudioDevices() {
    MMDeviceEnumerator deviceEnum = new MMDeviceEnumerator(Guid.NewGuid());
    return deviceEnum.EnumerateAudioEndPoints(DataFlow.Render, DeviceState.Active);
}

Cashier

Answer 3

This can now (actually for quite some time already) be done very easily using the AudioSwitcher.AudioApi.CoreAudio NuGet package.

Simply create a new CoreAudioController:

var controller = new AudioSwitcher.AudioApi.CoreAudio.CoreAudioController();

Get hold of the desired device using its GUID:

var device = controller.GetDevice(Guid.Parse(...));

And lastly set it as the default playback device:

controller.DefaultPlaybackDevice = device;

Footsie

I get error CS0200: Property or indexer 'AudioController<CoreAudioDevice>.DefaultPlaybackDevice' cannot be assigned to -- it is read only – Sporophyte

Okay so the API has changed but I can't get playbackDevice.SetAsDefault() to work either. Always returns false. – Sporophyte

@KenNetherland I'd suggest you open an issue on their GitHub page then, StackOverflow comments are usually not the best place to find answers to problems like these ;) – Footsie