Okay, here goes:
const int MAXPNAMELEN = 32;
const int MIXER_SHORT_NAME_CHARS = 16;
const int MIXER_LONG_NAME_CHARS = 64;
[Flags] enum MIXERLINE_LINEF : uint{
ACTIVE = 0x00000001,
DISCONNECTED = 0x00008000,
SOURCE = 0x80000000
}
[Flags] enum MIXER : uint{
GETLINEINFOF_DESTINATION = 0x00000000,
GETLINEINFOF_SOURCE = 0x00000001,
GETLINEINFOF_LINEID = 0x00000002,
GETLINEINFOF_COMPONENTTYPE = 0x00000003,
GETLINEINFOF_TARGETTYPE = 0x00000004,
GETLINEINFOF_QUERYMASK = 0x0000000F,
GETLINECONTROLSF_ALL = 0x00000000,
GETLINECONTROLSF_ONEBYID = 0x00000001,
GETLINECONTROLSF_ONEBYTYPE = 0x00000002,
GETLINECONTROLSF_QUERYMASK = 0x0000000F,
GETCONTROLDETAILSF_VALUE = 0x00000000,
GETCONTROLDETAILSF_LISTTEXT = 0x00000001,
GETCONTROLDETAILSF_QUERYMASK = 0x0000000F,
OBJECTF_MIXER = 0x00000000,
OBJECTF_WAVEOUT = 0x10000000,
OBJECTF_WAVEIN = 0x20000000,
OBJECTF_MIDIOUT = 0x30000000,
OBJECTF_MIDIIN = 0x40000000,
OBJECTF_AUX = 0x50000000,
OBJECTF_HANDLE = 0x80000000,
OBJECTF_HMIXER = OBJECTF_HANDLE | OBJECTF_MIXER,
OBJECTF_HWAVEOUT = OBJECTF_HANDLE | OBJECTF_WAVEOUT,
OBJECTF_HWAVEIN = OBJECTF_HANDLE | OBJECTF_WAVEIN,
OBJECTF_HMIDIOUT = OBJECTF_HANDLE | OBJECTF_MIDIOUT,
OBJECTF_HMIDIIN = OBJECTF_HANDLE | OBJECTF_MIDIIN
}
[Flags] enum MIXERCONTROL_CT : uint{
CLASS_MASK = 0xF0000000,
CLASS_CUSTOM = 0x00000000,
CLASS_METER = 0x10000000,
CLASS_SWITCH = 0x20000000,
CLASS_NUMBER = 0x30000000,
CLASS_SLIDER = 0x40000000,
CLASS_FADER = 0x50000000,
CLASS_TIME = 0x60000000,
CLASS_LIST = 0x70000000,
SUBCLASS_MASK = 0x0F000000,
SC_SWITCH_BOOLEAN = 0x00000000,
SC_SWITCH_BUTTON = 0x01000000,
SC_METER_POLLED = 0x00000000,
SC_TIME_MICROSECS = 0x00000000,
SC_TIME_MILLISECS = 0x01000000,
SC_LIST_SINGLE = 0x00000000,
SC_LIST_MULTIPLE = 0x01000000,
UNITS_MASK = 0x00FF0000,
UNITS_CUSTOM = 0x00000000,
UNITS_BOOLEAN = 0x00010000,
UNITS_SIGNED = 0x00020000,
UNITS_UNSIGNED = 0x00030000,
UNITS_DECIBELS = 0x00040000, /* in 10ths */
UNITS_PERCENT = 0x00050000, /* in 10ths */
}
[Flags] enum MIXERCONTROL_CONTROLTYPE : uint{
CUSTOM = MIXERCONTROL_CT.CLASS_CUSTOM | MIXERCONTROL_CT.UNITS_CUSTOM,
BOOLEANMETER = MIXERCONTROL_CT.CLASS_METER | MIXERCONTROL_CT.SC_METER_POLLED | MIXERCONTROL_CT.UNITS_BOOLEAN,
SIGNEDMETER = MIXERCONTROL_CT.CLASS_METER | MIXERCONTROL_CT.SC_METER_POLLED | MIXERCONTROL_CT.UNITS_SIGNED,
PEAKMETER = SIGNEDMETER + 1,
UNSIGNEDMETER = MIXERCONTROL_CT.CLASS_METER | MIXERCONTROL_CT.SC_METER_POLLED | MIXERCONTROL_CT.UNITS_UNSIGNED,
BOOLEAN = MIXERCONTROL_CT.CLASS_SWITCH | MIXERCONTROL_CT.SC_SWITCH_BOOLEAN | MIXERCONTROL_CT.UNITS_BOOLEAN,
ONOFF = BOOLEAN + 1,
MUTE = BOOLEAN + 2,
MONO = BOOLEAN + 3,
LOUDNESS = BOOLEAN + 4,
STEREOENH = BOOLEAN + 5,
BASS_BOOST = BOOLEAN + 0x00002277,
BUTTON = MIXERCONTROL_CT.CLASS_SWITCH | MIXERCONTROL_CT.SC_SWITCH_BUTTON | MIXERCONTROL_CT.UNITS_BOOLEAN,
DECIBELS = MIXERCONTROL_CT.CLASS_NUMBER | MIXERCONTROL_CT.UNITS_DECIBELS,
SIGNED = MIXERCONTROL_CT.CLASS_NUMBER | MIXERCONTROL_CT.UNITS_SIGNED,
UNSIGNED = MIXERCONTROL_CT.CLASS_NUMBER | MIXERCONTROL_CT.UNITS_UNSIGNED,
PERCENT = MIXERCONTROL_CT.CLASS_NUMBER | MIXERCONTROL_CT.UNITS_PERCENT,
SLIDER = MIXERCONTROL_CT.CLASS_SLIDER | MIXERCONTROL_CT.UNITS_SIGNED,
PAN = SLIDER + 1,
QSOUNDPAN = SLIDER + 2,
FADER = MIXERCONTROL_CT.CLASS_FADER | MIXERCONTROL_CT.UNITS_UNSIGNED,
VOLUME = FADER + 1,
BASS = FADER + 2,
TREBLE = FADER + 3,
EQUALIZER = FADER + 4,
SINGLESELECT = MIXERCONTROL_CT.CLASS_LIST | MIXERCONTROL_CT.SC_LIST_SINGLE | MIXERCONTROL_CT.UNITS_BOOLEAN,
MUX = SINGLESELECT + 1,
MULTIPLESELECT = MIXERCONTROL_CT.CLASS_LIST | MIXERCONTROL_CT.SC_LIST_MULTIPLE | MIXERCONTROL_CT.UNITS_BOOLEAN,
MIXER = MULTIPLESELECT + 1,
MICROTIME = MIXERCONTROL_CT.CLASS_TIME | MIXERCONTROL_CT.SC_TIME_MICROSECS | MIXERCONTROL_CT.UNITS_UNSIGNED,
MILLITIME = MIXERCONTROL_CT.CLASS_TIME | MIXERCONTROL_CT.SC_TIME_MILLISECS | MIXERCONTROL_CT.UNITS_UNSIGNED
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
struct MIXERLINE{
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
public struct TargetInfo{
public uint dwType;
public uint dwDeviceID;
public ushort wMid;
public ushort wPid;
public uint vDriverVersion;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAXPNAMELEN)]
public string szPname;
}
public uint cbStruct;
public uint dwDestination;
public uint dwSource;
public uint dwLineID;
public MIXERLINE_LINEF fdwLine;
public uint dwUser;
public uint dwComponentType;
public uint cChannels;
public uint cConnection;
public uint cControls;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=MIXER_SHORT_NAME_CHARS)]
public string szShortName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=MIXER_LONG_NAME_CHARS)]
public string szName;
public TargetInfo Target;
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
struct MIXERCONTROL{
[StructLayout(LayoutKind.Explicit)]
public struct BoundsInfo{
[FieldOffset(0)]
public int lMinimum;
[FieldOffset(4)]
public int lMaximum;
[FieldOffset(0)]
public uint dwMinimum;
[FieldOffset(4)]
public uint dwMaximum;
[FieldOffset(8), MarshalAs(UnmanagedType.ByValArray, SizeConst=4)]
public uint[] dwReserved;
}
[StructLayout(LayoutKind.Explicit)]
public struct MetricsInfo{
[FieldOffset(0)]
public uint cSteps;
[FieldOffset(0)]
public uint cbCustomData;
[FieldOffset(4), MarshalAs(UnmanagedType.ByValArray, SizeConst=5)]
public uint[] dwReserved;
}
public uint cbStruct;
public uint dwControlID;
public MIXERCONTROL_CONTROLTYPE dwControlType;
public uint fdwControl;
public uint cMultipleItems;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=MIXER_SHORT_NAME_CHARS)]
public string szShortName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=MIXER_LONG_NAME_CHARS)]
public string szName;
public BoundsInfo Bounds;
public MetricsInfo Metrics;
}
[StructLayout(LayoutKind.Explicit)]
struct MIXERLINECONTROLS{
[FieldOffset(0)]
public uint cbStruct;
[FieldOffset(4)]
public uint dwLineID;
[FieldOffset(8)]
public uint dwControlID;
[FieldOffset(8)] // not a typo! overlaps previous field
public uint dwControlType;
[FieldOffset(12)]
public uint cControls;
[FieldOffset(16)]
public uint cbmxctrl;
[FieldOffset(20)]
public IntPtr pamxctrl;
}
[StructLayout(LayoutKind.Explicit)]
struct MIXERCONTROLDETAILS{
[FieldOffset(0)]
public uint cbStruct;
[FieldOffset(4)]
public uint dwControlID;
[FieldOffset(8)]
public uint cChannels;
[FieldOffset(12)]
public IntPtr hwndOwner;
[FieldOffset(12)] // not a typo!
public uint cMultipleItems;
[FieldOffset(16)]
public uint cbDetails;
[FieldOffset(20)]
public IntPtr paDetails;
}
[StructLayout(LayoutKind.Sequential)]
struct VOLUME{
public int left;
public int right;
}
struct MixerInfo{
public uint volumeCtl;
public uint muteCtl;
public int minVolume;
public int maxVolume;
}
[DllImport("WinMM.dll", CharSet=CharSet.Auto)]
static extern uint mixerGetLineInfo (IntPtr hmxobj, ref MIXERLINE pmxl, MIXER flags);
[DllImport("WinMM.dll", CharSet=CharSet.Auto)]
static extern uint mixerGetLineControls (IntPtr hmxobj, ref MIXERLINECONTROLS pmxlc, MIXER flags);
[DllImport("WinMM.dll", CharSet=CharSet.Auto)]
static extern uint mixerGetControlDetails(IntPtr hmxobj, ref MIXERCONTROLDETAILS pmxcd, MIXER flags);
[DllImport("WinMM.dll", CharSet=CharSet.Auto)]
static extern uint mixerSetControlDetails(IntPtr hmxobj, ref MIXERCONTROLDETAILS pmxcd, MIXER flags);
static MixerInfo GetMixerControls(){
MIXERLINE mxl = new MIXERLINE();
MIXERLINECONTROLS mlc = new MIXERLINECONTROLS();
mxl.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERLINE));
mlc.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERLINECONTROLS));
mixerGetLineInfo(IntPtr.Zero, ref mxl, MIXER.OBJECTF_MIXER | MIXER.GETLINEINFOF_DESTINATION);
mlc.dwLineID = mxl.dwLineID;
mlc.cControls = mxl.cControls;
mlc.cbmxctrl = (uint)Marshal.SizeOf(typeof(MIXERCONTROL));
mlc.pamxctrl = Marshal.AllocHGlobal((int)(mlc.cbmxctrl * mlc.cControls));
mixerGetLineControls(IntPtr.Zero, ref mlc, MIXER.OBJECTF_MIXER | MIXER.GETLINECONTROLSF_ALL);
MixerInfo rtn = new MixerInfo();
for(int i = 0; i < mlc.cControls; i++){
MIXERCONTROL mxc = (MIXERCONTROL)Marshal.PtrToStructure((IntPtr)((int)mlc.pamxctrl + (int)mlc.cbmxctrl * i), typeof(MIXERCONTROL));
switch(mxc.dwControlType){
case MIXERCONTROL_CONTROLTYPE.VOLUME:
rtn.volumeCtl = mxc.dwControlID;
rtn.minVolume = mxc.Bounds.lMinimum;
rtn.maxVolume = mxc.Bounds.lMaximum;
break;
case MIXERCONTROL_CONTROLTYPE.MUTE:
rtn.muteCtl = mxc.dwControlID;
break;
}
}
Marshal.FreeHGlobal(mlc.pamxctrl);
return rtn;
}
static VOLUME GetVolume(MixerInfo mi){
MIXERCONTROLDETAILS mcd = new MIXERCONTROLDETAILS();
mcd.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERCONTROLDETAILS));
mcd.dwControlID = mi.volumeCtl;
mcd.cMultipleItems = 0;
mcd.cChannels = 2;
mcd.cbDetails = (uint)Marshal.SizeOf(typeof(int));
mcd.paDetails = Marshal.AllocHGlobal((int)mcd.cbDetails);
mixerGetControlDetails(IntPtr.Zero, ref mcd, MIXER.GETCONTROLDETAILSF_VALUE | MIXER.OBJECTF_MIXER);
VOLUME rtn = (VOLUME)Marshal.PtrToStructure(mcd.paDetails, typeof(VOLUME));
Marshal.FreeHGlobal(mcd.paDetails);
return rtn;
}
static bool IsMuted(MixerInfo mi){
MIXERCONTROLDETAILS mcd = new MIXERCONTROLDETAILS();
mcd.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERCONTROLDETAILS));
mcd.dwControlID = mi.muteCtl;
mcd.cMultipleItems = 0;
mcd.cChannels = 1;
mcd.cbDetails = 4;
mcd.paDetails = Marshal.AllocHGlobal((int)mcd.cbDetails);
mixerGetControlDetails(IntPtr.Zero, ref mcd, MIXER.GETCONTROLDETAILSF_VALUE | MIXER.OBJECTF_MIXER);
int rtn = Marshal.ReadInt32(mcd.paDetails);
Marshal.FreeHGlobal(mcd.paDetails);
return rtn != 0;
}
static void AdjustVolume(MixerInfo mi, int delta){
VOLUME volume = GetVolume(mi);
if(delta > 0){
volume.left = Math.Min(mi.maxVolume, volume.left + delta);
volume.right = Math.Min(mi.maxVolume, volume.right + delta);
}else{
volume.left = Math.Max(mi.minVolume, volume.left + delta);
volume.right = Math.Max(mi.minVolume, volume.right + delta);
}
SetVolume(mi, volume);
}
static void SetVolume(MixerInfo mi, VOLUME volume){
MIXERCONTROLDETAILS mcd = new MIXERCONTROLDETAILS();
mcd.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERCONTROLDETAILS));
mcd.dwControlID = mi.volumeCtl;
mcd.cMultipleItems = 0;
mcd.cChannels = 2;
mcd.cbDetails = (uint)Marshal.SizeOf(typeof(int));
mcd.paDetails = Marshal.AllocHGlobal((int)mcd.cbDetails);
Marshal.StructureToPtr(volume, mcd.paDetails, false);
mixerSetControlDetails(IntPtr.Zero, ref mcd, MIXER.GETCONTROLDETAILSF_VALUE | MIXER.OBJECTF_MIXER);
Marshal.FreeHGlobal(mcd.paDetails);
}
static void SetMute(MixerInfo mi, bool mute){
MIXERCONTROLDETAILS mcd = new MIXERCONTROLDETAILS();
mcd.cbStruct = (uint)Marshal.SizeOf(typeof(MIXERCONTROLDETAILS));
mcd.dwControlID = mi.muteCtl;
mcd.cMultipleItems = 0;
mcd.cChannels = 1;
mcd.cbDetails = 4;
mcd.paDetails = Marshal.AllocHGlobal((int)mcd.cbDetails);
Marshal.WriteInt32(mcd.paDetails, mute ? 1 : 0);
mixerSetControlDetails(IntPtr.Zero, ref mcd, MIXER.GETCONTROLDETAILSF_VALUE | MIXER.OBJECTF_MIXER);
Marshal.FreeHGlobal(mcd.paDetails);
}
This code is huge and ugly. It’s a translation of some C++ code, and with having to define all the P/Invoke stuff, it’s a lot more code. But I’ve tested it, and it works. To use it, you simply need something like:
MixerInfo mi = GetMixerControls();
AdjustVolume(mi, 100); // add 100 to the current volume
or
MixerInfo mi = GetMixerControls();
AdjustVolume(mi, (mi.maxVolume - mi.minVolume) / 10); // increase the volume by 10% of total range
or
MixerInfo mi = GetMixerControls();
SetVolume(mi, mi.maxVolume); // let's get this party crunk'd!
or
MixerInfo mi = GetMixerControls();
SetMute(mi, true); // shhhh!!!!!!
WARNING
Due to the use of fixed-sized ints and field offsets, this may fail fantastically on 64-bit Windows. I don’t know, I haven’t tested it and haven’t paid enough attention to know if these field sizes expand to 64 bits. caveat codor
EDIT
For the sake of simplicity (relatively speaking), I’ve left out any error handling. You should really check the return codes of all the mixerXXX functions, but I’ll leave that as an exercise for the reader (read as: I was too lazy to do this).