ボリュームミキサーを制御する

Question

他のアプリケーションボリューム（firefox）を制御したい。

私はVolume Mixer

Volume Mixerのライブラリーは何であるとそれを行うことができますか？

Answer 1

ここでは、それを行うサンプルのC＃コンソールアプリケーションを示します。これはWindows Core Audio Libraryに基づいています。 Windows 7以降でのみ動作します。

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); 
    } 
} 

注：インタフェースを完全に定義しておらず、コードが動作するために必要なものだけを定義しています。