Controlling Volume Mixer

Question

I want to control other application volume(firefox).

i can do it with Volume Mixer

What is the libraries of the Volume Mixer?

Answer 1

Here is a sample C# Console Application that does it. It's based on the Windows Core Audio Library. It works only on Windows 7 and higher.

using System; using System.Runtime.InteropServices; using System.Collections.Generic;  namespace SetAppVolumne {     class Program     {         static void Main(string[] args)         {             const string app = "Mozilla Firefox";              foreach (string name in EnumerateApplications())             {                 Console.WriteLine("name:" + name);                 if (name == app)                 {                     // display mute state & volume level (% of master)                     Console.WriteLine("Mute:" + GetApplicationMute(app));                     Console.WriteLine("Volume:" + GetApplicationVolume(app));                      // mute the application                     SetApplicationMute(app, true);                      // set the volume to half of master volume (50%)                     SetApplicationVolume(app, 50);                 }             }         }          public static float? GetApplicationVolume(string name)         {             ISimpleAudioVolume volume = GetVolumeObject(name);             if (volume == null)                 return null;              float level;             volume.GetMasterVolume(out level);             return level * 100;         }          public static bool? GetApplicationMute(string name)         {             ISimpleAudioVolume volume = GetVolumeObject(name);             if (volume == null)                 return null;              bool mute;             volume.GetMute(out mute);             return mute;         }          public static void SetApplicationVolume(string name, float level)         {             ISimpleAudioVolume volume = GetVolumeObject(name);             if (volume == null)                 return;              Guid guid = Guid.Empty;             volume.SetMasterVolume(level / 100, ref guid);         }          public static void SetApplicationMute(string name, bool mute)         {             ISimpleAudioVolume volume = GetVolumeObject(name);             if (volume == null)                 return;              Guid guid = Guid.Empty;             volume.SetMute(mute, ref guid);         }          public static IEnumerable<string> EnumerateApplications()         {             // get the speakers (1st render + multimedia) device             IMMDeviceEnumerator deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());             IMMDevice speakers;             deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);              // activate the session manager. we need the enumerator             Guid IID_IAudioSessionManager2 = typeof(IAudioSessionManager2).GUID;             object o;             speakers.Activate(ref IID_IAudioSessionManager2, 0, IntPtr.Zero, out o);             IAudioSessionManager2 mgr = (IAudioSessionManager2)o;              // enumerate sessions for on this device             IAudioSessionEnumerator sessionEnumerator;             mgr.GetSessionEnumerator(out sessionEnumerator);             int count;             sessionEnumerator.GetCount(out count);              for (int i = 0; i < count; i++)             {                 IAudioSessionControl ctl;                 sessionEnumerator.GetSession(i, out ctl);                 string dn;                 ctl.GetDisplayName(out dn);                 yield return dn;                 Marshal.ReleaseComObject(ctl);             }             Marshal.ReleaseComObject(sessionEnumerator);             Marshal.ReleaseComObject(mgr);             Marshal.ReleaseComObject(speakers);             Marshal.ReleaseComObject(deviceEnumerator);         }          private static ISimpleAudioVolume GetVolumeObject(string name)         {             // get the speakers (1st render + multimedia) device             IMMDeviceEnumerator deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());             IMMDevice speakers;             deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);              // activate the session manager. we need the enumerator             Guid IID_IAudioSessionManager2 = typeof(IAudioSessionManager2).GUID;             object o;             speakers.Activate(ref IID_IAudioSessionManager2, 0, IntPtr.Zero, out o);             IAudioSessionManager2 mgr = (IAudioSessionManager2)o;              // enumerate sessions for on this device             IAudioSessionEnumerator sessionEnumerator;             mgr.GetSessionEnumerator(out sessionEnumerator);             int count;             sessionEnumerator.GetCount(out count);              // search for an audio session with the required name             // NOTE: we could also use the process id instead of the app name (with IAudioSessionControl2)             ISimpleAudioVolume volumeControl = null;             for (int i = 0; i < count; i++)             {                 IAudioSessionControl ctl;                 sessionEnumerator.GetSession(i, out ctl);                 string dn;                 ctl.GetDisplayName(out dn);                 if (string.Compare(name, dn, StringComparison.OrdinalIgnoreCase) == 0)                 {                     volumeControl = ctl as ISimpleAudioVolume;                     break;                 }                 Marshal.ReleaseComObject(ctl);             }             Marshal.ReleaseComObject(sessionEnumerator);             Marshal.ReleaseComObject(mgr);             Marshal.ReleaseComObject(speakers);             Marshal.ReleaseComObject(deviceEnumerator);             return volumeControl;         }     }      [ComImport]     [Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")]     internal class MMDeviceEnumerator     {     }      internal enum EDataFlow     {         eRender,         eCapture,         eAll,         EDataFlow_enum_count     }      internal enum ERole     {         eConsole,         eMultimedia,         eCommunications,         ERole_enum_count     }      [Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface IMMDeviceEnumerator     {         int NotImpl1();          [PreserveSig]         int GetDefaultAudioEndpoint(EDataFlow dataFlow, ERole role, out IMMDevice ppDevice);          // the rest is not implemented     }      [Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface IMMDevice     {         [PreserveSig]         int Activate(ref Guid iid, int dwClsCtx, IntPtr pActivationParams, [MarshalAs(UnmanagedType.IUnknown)] out object ppInterface);          // the rest is not implemented     }      [Guid("77AA99A0-1BD6-484F-8BC7-2C654C9A9B6F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface IAudioSessionManager2     {         int NotImpl1();         int NotImpl2();          [PreserveSig]         int GetSessionEnumerator(out IAudioSessionEnumerator SessionEnum);          // the rest is not implemented     }      [Guid("E2F5BB11-0570-40CA-ACDD-3AA01277DEE8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface IAudioSessionEnumerator     {         [PreserveSig]         int GetCount(out int SessionCount);          [PreserveSig]         int GetSession(int SessionCount, out IAudioSessionControl Session);     }      [Guid("F4B1A599-7266-4319-A8CA-E70ACB11E8CD"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface IAudioSessionControl     {         int NotImpl1();          [PreserveSig]         int GetDisplayName([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);          // the rest is not implemented     }      [Guid("87CE5498-68D6-44E5-9215-6DA47EF883D8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]     internal interface ISimpleAudioVolume     {         [PreserveSig]         int SetMasterVolume(float fLevel, ref Guid EventContext);          [PreserveSig]         int GetMasterVolume(out float pfLevel);          [PreserveSig]         int SetMute(bool bMute, ref Guid EventContext);          [PreserveSig]         int GetMute(out bool pbMute);     } } 

Note: I have not defined the interfaces completely, only what was needed for the code to work.

Answer 2

I know this is too late, but I needed this lately, I tried Simon's answer and couldn't get it to work, tried ElektroStudios's comment and Simon's other answer and still nothing, I don't know what I did wrong but I gave up on it.

I later found this asnwer and got it to work using CSCore

private static void Main(string[] args) {     using (var sessionManager = GetDefaultAudioSessionManager2(DataFlow.Render))     {         using (var sessionEnumerator = sessionManager.GetSessionEnumerator())         {             foreach (var session in sessionEnumerator)             {                 using (var simpleVolume = session.QueryInterface<SimpleAudioVolume>())                 using (var sessionControl = session.QueryInterface<AudioSessionControl2>())                 {                     if (sessionControl.ProcessID == 2436)                         simpleVolume.MasterVolume = 0.5f;                 }             }         }     }      Console.ReadKey(); }  private static AudioSessionManager2 GetDefaultAudioSessionManager2(DataFlow dataFlow) {     using (var enumerator = new MMDeviceEnumerator())     {         using (var device = enumerator.GetDefaultAudioEndpoint(dataFlow, Role.Multimedia))         {             Debug.WriteLine("DefaultDevice: " + device.FriendlyName);             var sessionManager = AudioSessionManager2.FromMMDevice(device);             return sessionManager;         }     } }