Change the volume in Skype

You can use this simple program to control the volume of a given device using global hotkeys:

/* Small Volume Control Author: MSDN.WhiteKnight License: WTFPL Requirements: Windows Vista, .NET 4.5 (or newer) */ using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Text; using System.Runtime.InteropServices; using System.Windows.Forms; using System.Runtime.Serialization; using System.Xml; using System.Xml.Serialization; namespace SmallVolumeControl { static class Program { /// <summary> /// Главная точка входа для приложения. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } public class Form1 : Form { /// <summary> /// Требуется переменная конструктора. /// </summary> private System.ComponentModel.IContainer components = null; /// <summary> /// Освободить все используемые ресурсы. /// </summary> /// <param name="disposing">истинно, если управляемый ресурс должен быть удален; иначе ложно.</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Код, автоматически созданный конструктором форм Windows /// <summary> /// Обязательный метод для поддержки конструктора - не изменяйте /// содержимое данного метода при помощи редактора кода. /// </summary> private void InitializeComponent() { this.SuspendLayout(); // // Form1 // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(290, 117); this.Name = "Form1"; this.Text = "Form1"; this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.Form1_FormClosed); this.Load += new System.EventHandler(this.Form1_Load); this.ResumeLayout(false); } #endregion [DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] public static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk); [DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool UnregisterHotKey(IntPtr hWnd, int id); public const int WM_HOTKEY = 0x312; public Form1() { InitializeComponent(); } protected override void OnLoad(EventArgs e) { Visible = false; ShowInTaskbar = false; base.OnLoad(e); } protected override void WndProc(ref Message m) { try { if (m.Msg == WM_HOTKEY) { if ((int)m.WParam == 3) { this.Close(); return; } float f = Audio.Volume; switch ((int)m.WParam) { case 1: f -= Conf.Instance.Increment; break; case 2: f += Conf.Instance.Increment; break; } if (f < 0.0f) f = 0.0f; if (f > 1.0f) f = 1.0f; Audio.Volume = f; m.Result = (IntPtr)0; return; } } catch (Exception ex) { MessageBox.Show("Error: " + ex.ToString(), "Small Volume Control"); } base.WndProc(ref m); } private void Form1_Load(object sender, EventArgs e) { string path = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "volume.xml"); try { Conf conf; if (System.IO.File.Exists(path)) conf = Conf.Load(path); else { conf = new Conf(); conf.Save(path); } Conf.Instance = conf; bool res = RegisterHotKey(this.Handle, 1, 0, conf.DownKeyCode); if (res == false) MessageBox.Show("Error: RegisterHotKey failed", "Small Volume Control"); res = RegisterHotKey(this.Handle, 2, 0, conf.UpKeyCode); if (res == false) MessageBox.Show("Error: RegisterHotKey failed", "Small Volume Control"); this.Visible = false; res = RegisterHotKey(this.Handle, 3, 0, conf.ExitKeyCode); if (res == false) MessageBox.Show("Error: RegisterHotKey failed", "Small Volume Control"); this.Visible = false; } catch (Exception ex) { MessageBox.Show("Error: " + ex.ToString(), "Small Volume Control"); } } private void Form1_FormClosed(object sender, FormClosedEventArgs e) { try { UnregisterHotKey(this.Handle, 1); UnregisterHotKey(this.Handle, 2); UnregisterHotKey(this.Handle, 3); } catch (Exception ex) { MessageBox.Show("Error: " + ex.ToString(), "Small Volume Control"); } } } [Serializable] public class Conf { public string DeviceID { get; set; } public float Increment { get; set; } public uint DownKeyCode { get; set; } public uint UpKeyCode { get; set; } public uint ExitKeyCode { get; set; } public static Conf Instance { get; set; } public Conf() { Increment = 0.1f; DownKeyCode = (uint)Keys.F10; UpKeyCode = (uint)Keys.F11; ExitKeyCode = (uint)Keys.F9; DeviceID = ""; //Example: {0.0.0.00000000}.{954b1750-0438-45f0-87ed-a4c1167eb4f2} } public void Save(string file) { XmlSerializer xs = new XmlSerializer(typeof(Conf)); var obj = new Conf(); using (XmlWriter writer = XmlWriter.Create(file)) { xs.Serialize(writer, obj); } } public static Conf Load(string file) { XmlSerializer xs = new XmlSerializer(typeof(Conf)); using (XmlReader reader = XmlReader.Create(file)) { return (Conf)xs.Deserialize(reader); } } } [Guid("5CDF2C82-841E-4546-9722-0CF74078229A"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IAudioEndpointVolume { int f(); int g(); int h(); int i(); // Unused int SetMasterVolumeLevelScalar(float fLevel, System.Guid pguidEventContext); int j(); int GetMasterVolumeLevelScalar(out float pfLevel); int k(); int l(); int m(); int n(); int SetMute([MarshalAs(UnmanagedType.Bool)] bool bMute, System.Guid pguidEventContext); int GetMute(out bool pbMute); } [Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IMMDevice { int Activate(ref System.Guid id, int clsCtx, int activationParams, out IAudioEndpointVolume aev); } [Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IMMDeviceEnumerator { int f(); // Unused int GetDefaultAudioEndpoint(int dataFlow, int role, out IMMDevice endpoint); int GetDevice(string pwstrId, out IMMDevice endpoint); } [ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")] class MMDeviceEnumeratorComObject { } public class Audio { static IAudioEndpointVolume Vol() { IMMDeviceEnumerator enumerator = new MMDeviceEnumeratorComObject() as IMMDeviceEnumerator; IMMDevice dev = null; Marshal.ThrowExceptionForHR(enumerator.GetDevice(Conf.Instance.DeviceID, out dev)); IAudioEndpointVolume epv = null; System.Guid epvid = typeof(IAudioEndpointVolume).GUID; Marshal.ThrowExceptionForHR(dev.Activate(ref epvid, /*CLSCTX_ALL*/ 23, 0, out epv)); return epv; } public static float Volume { get { float v = -1; Marshal.ThrowExceptionForHR(Vol().GetMasterVolumeLevelScalar(out v)); return v; } set { Marshal.ThrowExceptionForHR(Vol().SetMasterVolumeLevelScalar(value, System.Guid.Empty)); } } public static bool Mute { get { bool mute; Marshal.ThrowExceptionForHR(Vol().GetMute(out mute)); return mute; } set { Marshal.ThrowExceptionForHR(Vol().SetMute(value, System.Guid.Empty)); } } } } 

Build command:

 %WINDIR%\Microsoft.NET\Framework\v4.0.30319\Csc.exe /noconfig /nowarn:1701,1702,2008 /nostdlib+ /platform:anycpu32bitpreferred /errorreport:prompt /warn:4 /define:TRACE /errorendlocation /preferreduilang:ru-RU /highentropyva+ /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Microsoft.CSharp.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\mscorlib.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Core.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Data.DataSetExtensions.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Data.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Deployment.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Drawing.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Windows.Forms.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Xml.dll" /reference:"%ProgramFiles(x86)%\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Xml.Linq.dll" /debug:pdbonly /filealign:512 /optimize+ /out:SmallVolumeControl.exe /subsystemversion:6.00 /target:winexe /utf8output Program.cs 

It is configured through the My Documents \ volume.xml file :

DeviceID - A string of the form "{0.0.0.00000000}. {GUID}", where GUID is the name of the subkey in the HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ MMDevices \ Audio \ Render registry key corresponding to the device you need

Increment - Volume change step (0.1 = 10%)

DownKeyCode - Virtual key code to reduce the volume

UpKeyCode - Virtual Key Code for Volume Up

ExitKeyCode - Virtual key code for exiting the program

The code from the answer to SO is used: https://stackoverflow.com/a/31751275/8674428

Put in the "playback devices windows" headphones by default.

If for some reason this fails, it may help to disconnect the speakers from the computer (logically, then the headphones will become the default sound device).