Using Remote Control Input Outside of Windows Media Center

Article
09/23/2009

This topic describes the Windows commands generated by the remote control device driver and how to retrieve them so that your application can respond appropriately to input.

The following table shows the associated messages and keyboard equivalents for the compulsory and optional buttons on the remote control.

Button	Message	Command	Keyboard equivalent
#	To be determined	—	SHIFT+3
*	To be determined	—	SHIFT+8
Back	WM_APPCOMMAND	APPCOMMAND_BROWSER_BACK	BACKSPACE
Chan/Page Down	WM_APPCOMMAND	APPCOMMAND_MEDIA_CHANNEL_DOWN	MINUS SIGN (-) CTRL+MINUS SIGN PAGE DOWN
Chan/Page Up	WM_APPCOMMAND	APPCOMMAND_MEDIA_CHANNEL_UP	PLUS SIGN (+) CTRL+SHIFT+PLUS SIGN PAGE UP
Clear	WM_KEYDOWN	VK_ESCAPE	ESC
Details	WM_INPUT	—	—
Down	WM_KEYDOWN	VK_DOWN	DOWN ARROW
DVD Angle	WM_INPUT	—	—
DVD Audio	WM_INPUT	—	—
DVD Menu	WM_INPUT	—	—
DVD Subtitle	WM_INPUT	—	—
eHome	Not for use by applications.	—	—
Enter	VK_RETURN	—	ENTER
Fwd	WM_APPCOMMAND	APPCOMMAND_MEDIA_FASTFORWARD	CTRL+SHIFT+F
Guide	WM_INPUT	—	—
Left	WM_KEYDOWN	VK_LEFT	LEFT ARROW
Mute	WM_APPCOMMAND	APPCOMMAND_VOLUME_MUTE	F8
My Music	WM_INPUT	—	—
My Pictures	WM_INPUT	—	—
Recorded TV	WM_INPUT	—	—
My TV	WM_INPUT	—	—
My Videos	WM_INPUT	—	—
Number keys	WM_KEYDOWN	VK_0 to VK_9	0 to 9
OEM1	WM_INPUT	—	—
OEM2	WM_INPUT	—	—
OK	WM_KEYDOWN	VK_RETURN	ENTER SPACEBAR
Pause	WM_APPCOMMAND	APPCOMMAND_MEDIA_PAUSE	CTRL+P
Play	WM_APPCOMMAND	APPCOMMAND_MEDIA_PLAY	CTRL+SHIFT+P
Record	WM_APPCOMMAND	APPCOMMAND_MEDIA_RECORD	CTRL+R
Replay	WM_APPCOMMAND	APPCOMMAND_MEDIA_PREVIOUSTRACK	CTRL+B
Rewind	WM_APPCOMMAND	APPCOMMAND_MEDIA_REWIND	—
Right	WM_KEYDOWN	VK_RIGHT	RIGHT ARROW
Skip	WM_APPCOMMAND	APPCOMMAND_MEDIA_NEXTTRACK	CTRL+F
Standby	WM_INPUT	—	—
Stop	WM_APPCOMMAND	APPCOMMAND_MEDIA_STOP	CTRL+S
Up	WM_KEYDOWN	VK_UP	UP ARROW
TV/Jump	WM_INPUT	—	—
Vol Down	WM_APPCOMMAND	APPCOMMAND_VOLUME_DOWN	F9
Vol Up	WM_APPCOMMAND	APPCOMMAND_VOLUME_UP	F10

Buttons that generate WM_INPUT messages are defined according to the Human Interface Device (HID) specification. The following table shows the HID mapping of these buttons.

Button	Usage page	Page name	Collection usage ID	Button usage ID
Details	0x0C	Consumer controls	0x01	0x209 (AC properties)
DVD Angle	0xFFBC	Vendor-defined	0x88	0x4B
DVD Audio	0xFFBC	Vendor-defined	0x88	0x4C
DVD Menu	0xFFBC	Vendor-defined	0x88	0x24
DVD Subtitle	0xFFBC	Vendor-defined	0x88	0x4D
Guide	0x0C	Consumer controls	0x01	0x8D (AC Program Guide)
My Music	0xFFBC	Vendor-defined	0x88	0x47
My Pictures	0xFFBC	Vendor-defined	0x88	0x49
My TV	0xFFBC	Vendor-defined	0x88	0x46
My Videos	0xFFBC	Vendor-defined	0x88	0x4A
OEM1	0xFFBC	Vendor-defined	0x88	0x80
OEM2	0xFFBC	Vendor-defined	0x88	0x81
Recorded TV	0xFFBC	Vendor-defined	0x88	0x48
Standby	0x01	Generic desktop	0x80	0x82
TV/Jump	0xFFBC	Vendor-defined	0x88	0x25

To process WM_INPUT messages, the application must first register the devices from which it receives data. You can do this by using the Win32® function RegisterRawInputDevices. Each RAWINPUTDEVICE structure passed to this function specifies one usage page and usage.

The following example C++ code registers the device to receive input from the controls defined on the vendor-defined usage page that have a usage of 0x88:

RAWINPUTDEVICE Rid[1];

Rid[0].usUsagePage = 0xFFBC; 
Rid[0].usUsage = 0x88; 
Rid[0].dwFlags = 0;

if (RegisterRawInputDevices(Rid, 1, sizeof(Rid[0])) == FALSE) 
{
    ErrorExit();  // Add error-handling code here.
}

To identify the event that triggered a WM_INPUT message, your application must parse the data passed to the window procedure as the lParam parameter.

If you are using the Microsoft .NET Framework, you must implement the WndProc method to retrieve messages. The WndProc method is a member of the NativeWindow class found in the System.Windows.Forms namespace. The overridden method is called each time a new message is placed in the form's message queue. Before returning, the method must call the base WndProc method to ensure that unprocessed messages are handled properly.

The following C# code shows how to use the WndProc method to retrieve WM_KEYDOWN messages:

using System.Windows.Forms;
.
.
.
class Form1Window : NativeWindow
{ 
  private const int WM_KEYDOWN = 0x0100;
  private int iChar;
  public Form1 form;
 
  protected override void WndProc(ref Message message)
  {
    // Handle the navigation and numeric buttons.
 
    if (message.Msg == WM_KEYDOWN)
    {
      iChar = message.WParam.ToInt32();
 
      switch(iChar)
      {
        case (int)Keys.D0:
          // Handle 0 key here.  
          break;
       // Insert more cases here.
.
.
.
      }  // End switch.
    }    // End key messages.
    base.WndProc(ref message);
  }      // End WndProc
}        // End class.

In the initialization code for the main form, you must create an instance of the Form1Window class and assign the main form to it, as follows:

public Form1()
{
  InitializeComponent();
  Form1Window win = new Form1Window();
  win.form = this;
  win.AssignHandle(this.Handle);
}

To learn more about Human Interface Device (HID) and the structure of HID data, see the USB home page (http://www.usb.org).

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Using Remote Control Input Outside of Windows Media Center

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