Populated.

Enums.cs

@@ -0,0 +1,35 @@
+using System;
+
+namespace SwitchSound
+{
+  [Flags]
+  enum EDeviceState : uint
+  {
+    Active = 1,
+    Disabled = 2,
+    NotPresent = 4,
+    Unplugged = 8,
+    All = Active | Disabled | NotPresent | Unplugged
+  }
+
+  enum EDataFlow
+  {
+    Render,
+    Capture,
+    All
+  }
+
+  enum ERole
+  {
+    Console,
+    Multimedia,
+    Communications
+  }
+
+  enum StorageAccessMode : uint
+  {
+    Read,
+    Write,
+    ReadWrite
+  }
+}

MultimediaDevice.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [Guid("D666063F-1587-4E43-81F1-B948E807363F")]
+  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+  interface IMultimediaDevice
+  {
+    void Activate();
+    IPropertyStore OpenPropertyStore(StorageAccessMode accessMode);
+    string Id { [return : MarshalAs(UnmanagedType.LPWStr)] get; }
+  }
+
+  static class MultimediaDevice
+  {
+    static PropertyKey PKEY_DEVICE_FRIENDLY_NAME = new PropertyKey(new Guid("A45C254E-DF1C-4EFD-8020-67D146A850E0"), 14);
+    public static string Name(this IMultimediaDevice device) => device.OpenPropertyStore(StorageAccessMode.Read).GetValue(ref PKEY_DEVICE_FRIENDLY_NAME).AsString;
+  }
+}

MultimediaDeviceCollection.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [Guid("0BD7A1BE-7A1A-44DB-8397-CC5392387B5E")]
+  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+  interface IMultimediaDeviceCollection
+  {
+    uint Count { get; }
+    IMultimediaDevice this[uint index] { get; }
+  }
+
+  static class MultimediaDeviceCollection
+  {
+    public static IEnumerable<IMultimediaDevice> ToEnumerable(this IMultimediaDeviceCollection collection)
+    {
+      for (uint i = 0, n = collection.Count; i < n; ++i)
+        yield return collection[i];
+    }
+  }
+}

MultimediaDeviceEnumerator.cs

@@ -0,0 +1,17 @@
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [Guid("A95664D2-9614-4F35-A746-DE8DB63617E6")]
+  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+  interface IMultimediaDeviceEnumerator
+  {
+    IMultimediaDeviceCollection EnumAudioEndpoints(EDataFlow dataFlow, EDeviceState stateMask);
+    IMultimediaDevice GetDefaultAudioEndpoint(EDataFlow dataFlow, ERole role);
+  }
+
+  [ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")]
+  class MultimediaDeviceEnumerator
+  {
+  }
+}

PolicyConfig.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [Guid("F8679F50-850A-41CF-9C72-430F290290C8")]
+  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+  internal interface IPolicyConfig
+  {
+    void GetMixFormat();
+    void GetDeviceFormat();
+    void ResetDeviceFormat();
+    void SetDeviceFormat();
+    void GetProcessingPeriod();
+    void SetProcessingPeriod();
+    void GetShareMode();
+    void SetShareMode();
+    void GetPropertyValue();
+    void SetPropertyValue();
+    void SetDefaultEndpoint([MarshalAs(UnmanagedType.LPWStr)] string pszDeviceName, ERole role);
+  }
+
+  [ComImport, Guid("870AF99C-171D-4F9E-AF0D-E63DF40C2BC9")]
+  class PolicyConfig
+  {
+  }
+}

Program.cs

@@ -0,0 +1,37 @@
+using System;
+
+namespace SwitchSound
+{
+  class Program
+  {
+    static void Main(string[] args)
+    {
+      try
+      {
+        var devices = (IMultimediaDeviceEnumerator)new MultimediaDeviceEnumerator();
+        var default_id = devices.GetDefaultAudioEndpoint(EDataFlow.Render, ERole.Multimedia).Id;
+
+        if (args.Length < 1)
+          foreach (var device in devices.EnumAudioEndpoints(EDataFlow.Render, EDeviceState.Active).ToEnumerable())
+          {
+            var id = device.Id;
+            Console.WriteLine("{0}{1}\n {2}\n", id == default_id ? "*" : " ", device.Name(), id);
+          }
+        else
+        {
+          var new_default_id = args[0];
+          if (new_default_id == default_id)
+          {
+            if (args.Length < 2) return;
+            new_default_id = args[1];
+          }
+          ((IPolicyConfig)new PolicyConfig()).SetDefaultEndpoint(new_default_id, ERole.Multimedia);
+        }
+      }
+      catch (Exception e)
+      {
+        Console.Error.WriteLine(e.Message);
+      }
+    }
+  }
+}

PropVariant.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [StructLayout(LayoutKind.Sequential)]
+  struct PropVariant
+  {
+    short vt;
+    short wReserved1;
+    short wReserved2;
+    short wReserved3;
+    IntPtr LPWSTR;
+
+    public string AsString => (VarEnum)vt == VarEnum.VT_LPWSTR ? Marshal.PtrToStringUni(LPWSTR) : null;
+  }
+}

Properties/AssemblyInfo.cs

@@ -0,0 +1,35 @@
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("SwitchSound")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("SwitchSound")]
+[assembly: AssemblyCopyright("Copyright © 2017 Sergey Nozhenko")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible 
+// to COM components.  If you need to access a type in this assembly from 
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("71716191-d69b-4409-bfca-d3a9579e03ca")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers 
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

PropertyKey.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [StructLayout(LayoutKind.Sequential)]
+  struct PropertyKey
+  {
+    public Guid FormatId;
+    public uint PropertyId;
+
+    public PropertyKey(Guid formatId, uint propertyId)
+    {
+      FormatId = formatId;
+      PropertyId = propertyId;
+    }
+  }
+}

PropertyStore.cs

@@ -0,0 +1,13 @@
+using System.Runtime.InteropServices;
+
+namespace SwitchSound
+{
+  [Guid("886D8EEB-8CF2-4446-8D02-CDBA1DBDCF99")]
+  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+  interface IPropertyStore
+  {
+    void GetCount();
+    void GetAt();
+    PropVariant GetValue(ref PropertyKey propertyKey);
+  }
+}

README.md

@@ -1 +1,53 @@
-# SwitchSound
+# SwitchSound
+
+A tiny console tool for switching between audio output devices.
+
+#### Run:
+
+ - Without agruments - list devices with their interface identifiers.
+   Currently active is marked with '*'.
+
+ - With a list of interface identifiers as arguments - switch between devices in a circle: active -> next, last -> first.
+
+#### For example:
+
+```
+> SwitchSound.exe
+
+*S22E390 (HD Audio Driver for Display Audio)
+ {0.0.0.00000000}.{24a8b3c5-8ece-48eb-9980-cf104f3ff711}
+
+ Digital Audio (S/PDIF) (High Definition Audio Device)
+ {0.0.0.00000000}.{42b8a793-61c3-430d-a214-d43c9b086421}
+
+ Speakers (High Definition Audio Device)
+ {0.0.0.00000000}.{a4a19331-61d9-46d4-8118-33c5003c1c20}
+
+
+> SwitchSound.exe {0.0.0.00000000}.{24a8b3c5-8ece-48eb-9980-cf104f3ff711} {0.0.0.00000000}.{a4a19331-61d9-46d4-8118-33c5003c1c20}
+> SwitchSound.exe
+
+ S22E390 (HD Audio Driver for Display Audio)
+ {0.0.0.00000000}.{24a8b3c5-8ece-48eb-9980-cf104f3ff711}
+
+ Digital Audio (S/PDIF) (High Definition Audio Device)
+ {0.0.0.00000000}.{42b8a793-61c3-430d-a214-d43c9b086421}
+
+*Speakers (High Definition Audio Device)
+ {0.0.0.00000000}.{a4a19331-61d9-46d4-8118-33c5003c1c20}
+
+
+> SwitchSound.exe {0.0.0.00000000}.{24a8b3c5-8ece-48eb-9980-cf104f3ff711} {0.0.0.00000000}.{a4a19331-61d9-46d4-8118-33c5003c1c20}
+> SwitchSound.exe
+
+*S22E390 (HD Audio Driver for Display Audio)
+ {0.0.0.00000000}.{24a8b3c5-8ece-48eb-9980-cf104f3ff711}
+
+ Digital Audio (S/PDIF) (High Definition Audio Device)
+ {0.0.0.00000000}.{42b8a793-61c3-430d-a214-d43c9b086421}
+
+ Speakers (High Definition Audio Device)
+ {0.0.0.00000000}.{a4a19331-61d9-46d4-8118-33c5003c1c20}
+```
+
+A typical usage is to create a shortcut with arguments to switch between selected devices and assign it to a hotkey.

SwitchSound.csproj

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{71716191-D69B-4409-BFCA-D3A9579E03CA}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>SwitchSound</RootNamespace>
+    <AssemblyName>SwitchSound</AssemblyName>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>none</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup>
+    <ApplicationIcon>SwitchSound.ico</ApplicationIcon>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Enums.cs" />
+    <Compile Include="MultimediaDevice.cs" />
+    <Compile Include="MultimediaDeviceCollection.cs" />
+    <Compile Include="MultimediaDeviceEnumerator.cs" />
+    <Compile Include="PolicyConfig.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="PropertyKey.cs" />
+    <Compile Include="PropertyStore.cs" />
+    <Compile Include="PropVariant.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <Content Include="SwitchSound.ico" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>