Lit of Winamp's CMD + WM_COMMAND

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Using the command line interface to control Winamp

The simplest, easiest, least powerful way of controlling Winamp is to execute winamp.exe yourself. By simply calling winamp.exe with various command line options, you do a number of things. For example:

code:
C:\path\to\winamp\winamp.exe /ADD C:\mp3\whatever.mp3

(Adds C:\mp3\whatever.mp3 to the playlist of a running Winamp, if Winamp is running, otherwise it opens Winamp and plays it outright)

code:
C:\path\to\winamp\winamp.exe /NEW

(Creates a new instance of Winamp, even if Winamp is already running)

code:
C:\path\to\winamp\winamp.exe C:\mp3\file.mp3

(Plays the file C:\mp3\file.mp3, regardless of whether or not Winamp is open)

code:
C:\path\to\winamp\winamp.exe /CLASS="myclassname"

(Opens Winamp with a different Window Class name "myclassname")



As you might notice, what you can actually do using the command line interface is pretty limited. It is really easy to get started with, though. You can also specify multiple files and or directories on the command line, such as:

code:
C:\path\to\winamp\winamp.exe /NEW "C:\my mp3s\" "C:\bigplaylist.pls" "C:\download\new song.mp3"

Using Windows Messages to control Winamp
Determining the Winamp window
Winamp is a 32-bit Windows application. Having said that, we'll assume some basic knowledge of 32 bit Windows programming. Winamp can be controlled using the Windows Message system. Before you can send Winamp messages, you have to determine its Window Handle. There are two primary ways of doing that, one for external applications, and another for plug-ins.

Plug-ins simply get passed a HWND to Winamp in their respective structures. The variable is usually named hwndWinamp or hwndParent.

External applications can find the Winamp window using the following pieces of code:
C/C++:

code:
HWND hwndWinamp = FindWindow("Winamp v1.x",NULL);

VBasic

code:
Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Dim hwndWinamp as long

hwndWinamp = FindWindow("Winamp v1.x",vbNullString)

Delphi Pascal

code:
var hwndWinamp : THandle;

hwndWinamp := FindWindow('Winamp v1.x', nil);

Note that this code uses the FindWindow() function to find a window of any title whose class name is "Winamp v1.x". All versions of Winamp 1.x and 2.x have the class "Winamp v1.x", unless changed using the /CLASS= switch (see above). Note that if you want to run multiple Winamp's and easily tell the difference between them, you can use the /CLASS= switch.

Message types Winamp understands
Winamp responds to three messages in particular: WM_USER, WM_COMMAND, and WM_COPYDATA. WM_USER and WM_COPYDATA allow you to control some of the more advanced aspects of Winamp while WM_COMMAND lets you do simple things such as simulate the pause button being pressed.

WM_COMMAND Messages

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WM_COMMAND Messages

code:
Previous track button			40044

Next track button			40048

Play button				40045

Pause/Unpause button			40046

Stop button				40047

Fadeout and stop			40147

Stop after current track		40157

Fast-forward 5 seconds			40148

Fast-rewind 5 seconds			40144

Start of playlist			40154

Go to end of playlist			40158

Open file dialog			40029

Open URL dialog				40155

Open file info box			40188

Set time display mode to elapsed	40037

Set time display mode to remaining	40038

Toggle preferences screen		40012

Open visualization options		40190

Open visualization plug-in options	40191

Execute current visualization plug-in	40192

Toggle about box			40041

Toggle title Autoscrolling		40189

Toggle always on top			40019

Toggle Windowshade			40064

Toggle Playlist Windowshade		40266

Toggle doublesize mode			40165

Toggle EQ				40036

Toggle playlist editor			40040

Toggle main window visible		40258

Toggle minibrowser			40298

Toggle easymove				40186

Raise volume by 1%			40058

Lower volume by 1%			40059

Toggle repeat				40022

Toggle shuffle				40023

Open jump to time dialog		40193

Open jump to file dialog		40194

Open skin selector			40219

Configure current visualization plug-in	40221

Reload the current skin			40291

Close Winamp				40001

Moves back 10 tracks in playlist	40197

Show the edit bookmarks			40320

Adds current track as a bookmark	40321

Play audio CD				40323

Load a preset from EQ			40253

Save a preset to EQF			40254

Opens load presets dialog		40172

Opens auto-load presets dialog		40173

Load default preset			40174

Opens save preset dialog		40175

Opens auto-load save preset		40176

Opens delete preset dialog		40178

Opens delete an auto load preset dialog	40180