winmm.dll mciSendString - How to loop from specific song point?

Question

Hi,

I'm using a background program and playing MP3 with mciSendString with commands like "play Mediafile Repeat".

However, my songs usually have an Introduction and then the looping part (as videogames). So I want that the song start playing normally, but the looping point been at some point.

Thanks!!

Answer 1

You can do :

"set your_mp3 time format ms"
then
"play your_mp3 notify" (with window handle to receive MM_MCINOTIFY

then in MM_MCINOTIFY :
"seek your_mp3 to n" (where n = nb of milliseconds, for example 2000 for 2 seconds)
then again
"play your_mp3 notify"

(tested on Windows 10)

Answer 2

Hi, DavidG-0663 I assume that the file you want to play is 20 seconds long, and want to loop from10s to 15s, you can use the following steps:

1. Create a window, which can be a message-only window (invisible)
2. Set the time format to ms.
3. Play to 15s and notify the window.
4. Play from 10s-15s and set notify again.
5. Play to the end.

Try the following sample:

#include <windows.h>  
#pragma comment(lib, "winmm.lib")  
  
MCIDEVICEID wDeviceID;  
static int loop_count = 3;  
  
MCIDEVICEID MCIOpen(LPCTSTR strPath)  
{  
    MCI_OPEN_PARMS mciOP = {0};  
    DWORD opReturn;  
    mciOP.lpstrDeviceType = NULL;  
    mciOP.lpstrElementName = strPath;  //Set the .wav file name to open  
    opReturn = mciSendCommand(NULL, MCI_OPEN, MCI_OPEN_ELEMENT, (DWORD)(LPVOID)&mciOP);  
    if (!opReturn)  
        return mciOP.wDeviceID;  
    return -1;  
}  
  
DWORD MCISetTimeFormat(MCIDEVICEID wDeviceID, DWORD timeformat)  
{  
    MCI_SET_PARMS mciSet = {0};  
    mciSet.dwTimeFormat = timeformat;//set time format to milliseconds  
  
    return mciSendCommand(wDeviceID, MCI_SET, MCI_SET_TIME_FORMAT, (DWORD)(LPVOID)&mciSet);  
}  
  
DWORD MCIPlayTo(HWND hwnd, MCIDEVICEID wDeviceID, int sec)  
{  
    MCI_PLAY_PARMS mciPP;  
    mciPP.dwCallback = (DWORD_PTR)hwnd;  
    mciPP.dwTo = sec * 1000;  
    return mciSendCommand(wDeviceID, MCI_PLAY, MCI_NOTIFY | MCI_TO, (DWORD)&mciPP);  
}  
DWORD MCIPlayFromTo(HWND hwnd, MCIDEVICEID wDeviceID, int secFrom, int secTo)  
{  
    MCI_PLAY_PARMS play = {0};  
    play.dwFrom = secFrom * 1000;   //Looping From sec*1000 ms  
    play.dwTo = secTo * 1000;   //Looping To sec*1000 ms  
    play.dwCallback = (DWORD_PTR)hwnd;  
    DWORD_PTR dwParam1;  
    if (secTo == 0)  
        dwParam1 = MCI_NOTIFY | MCI_FROM;  
    else  
        dwParam1 = MCI_NOTIFY | MCI_FROM | MCI_TO;  
    return mciSendCommand(wDeviceID, MCI_PLAY, dwParam1, (DWORD)&play);  
}  
  
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)  
{  
    switch (message)  
    {  
    case MM_MCINOTIFY:  
    {  
        if (MCI_NOTIFY_SUCCESSFUL == wParam) //MCI_NOTIFY_SUCCESSFUL means that the song has been played successfully.   
        {  
            //To Do  
            if (--loop_count > 0)  
                MCIPlayFromTo(hWnd, wDeviceID, 10, 15);  
            else  
                MCIPlayFromTo(hWnd, wDeviceID, 15, 0); //to the end;  
        }  
    }  
    break;  
    default:  
        return DefWindowProc(hWnd, message, wParam, lParam);  
    }  
    return 0;  
}  
  
int main()  
{  
    DWORD opReturn;  
    static const WCHAR* class_name = L"DUMMY_CLASS";  
    WNDCLASSEX wx = {};  
  
    wx.cbSize = sizeof(WNDCLASSEX);  
    wx.lpfnWndProc = WndProc;        // function which will handle messages  
    wx.hInstance = GetModuleHandleA(NULL);  
    wx.lpszClassName = class_name;  
    if (!RegisterClassEx(&wx)) {  
        return 0;  
    }  
    HWND hwnd = CreateWindowEx(0, class_name, L"dummy_name", 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);  
    //open device  
    wDeviceID = MCIOpen(L"test.wav");  //Save DeviceID  
    opReturn = MCISetTimeFormat(wDeviceID, MCI_FORMAT_MILLISECONDS);  
      
    if (wDeviceID != -1)  
    {  
        opReturn = MCIPlayTo(hwnd, wDeviceID, 15);  
    }  
    HACCEL hAccelTable = LoadAccelerators(wx.hInstance, class_name);  
    MSG msg;  
    while (GetMessage(&msg, nullptr, 0, 0))  
    {  
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))  
        {  
            TranslateMessage(&msg);  
            DispatchMessage(&msg);  
        }  
    }  
    return 0;  
}  

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Answer 3

Thanks for the answers.

I have to check the "notify" as Im using Lua on CheatEngine and importing the DLL there, so I don't really know how to handle that kind of messages right now as I have just started to use this DLL.

I will take a look during the weekend.

If you have any tip about doing it on Lua CE, it will be appreciated. Thanks in advance!