Play manipulated volume levels in PlaySound with SND_MEMORY

Question

I'm facing a problem for playing a wav file which is first read into BYTE array and modifying it to decrease its volume level. The snippet I made to achieve it is taken from various web sources.

However it works well when I run the program through Visual Studio 2013 Community.

But when coming to the executable generated in Release x64 mode, it gives a runtime error and I can't hear anything (that also can't be caught using try-catch).

I want my executable to work but it works only when I comment out the line --> p[i] = (__int8)((float)p[i] * fVolume); <-- , which is actually doing the work to manipulate the volume level.

I am unable to understand why the exe is not working and Visual Studio can easily run it in Release x64 mode.

WAV file being manipulated : https://drive.google.com/file/d/1i3DACTJxRCQQqRKBK_XL4msuw5p__kXg/view?usp=sharing Function call I'm using: PlaySound_Volume("right_10.wav", 0.235);

Thanks for your attention !

void PlaySound_Volume(string fname, float fVolume = 1, bool async = false){
    DWORD dwFileSize;
    BYTE* pFileBytes;

    ifstream f(fname, ios::binary);

    f.seekg(0, ios::end);
    int lim = f.tellg();
    dwFileSize = lim;

    pFileBytes = new BYTE[lim];
    f.seekg(0, ios::beg);

    f.read((char *)pFileBytes, lim);

    f.close();


    BYTE* pDataOffset = (pFileBytes + 40);

    __int8 * p = (__int8 *)(pDataOffset + 8);
    for (int i = 80 / sizeof(*p); i < dwFileSize / sizeof(*p); i++){
// COMMENT FOLLOWING LINE
        p[i] = (__int8)((float)p[i] * fVolume);

    }


    if (async)
        PlaySound((LPCSTR)pFileBytes, NULL, SND_MEMORY | SND_ASYNC);
    else
        PlaySound((LPCSTR)pFileBytes, NULL, SND_MEMORY);
}

Answer 1

Since p is pFileBytes + 48, you're not allowed to dereference p at dwFileSize - 48 or beyond.
Or, put another way,pFileBytes points to the first of dwFileSize bytes, but p points to the first of dwFileSize - 48 bytes.

Adjust your loop boundary.