Of course inline! Actually you can remove the masking for the 24 bit shifts. For the inner two bytes I don't see an improvement. Thanks Gary for the follow up :) Jürgen Eidt http://cpicture.de/en

Thanks Gary, that a good way to do it! Jürgen Eidt http://cpicture.de/en

Didn't thought of a union :) But even swapping with the xor trick I'm not sure how the compiler optimization would be. I guess looking at the asm code would make the final judgement. Thanks. Jürgen Eidt http://cpicture.de/en

What is the fasted way to swap bytes in a ushort/ulong? For example: 0x1234 -> 0x3412 0x12345678 -> 0x78563412

unsigned short short_exch(const unsigned short a)
{
    // 0x1234 -> 0x3412
    return (a << 8) + (a >> 8);
};


unsigned long long_exch(unsigned long a)
{
    // 0x12345678 -> 0x78563412

    unsigned long t = a&0xff;
    a >>= 8;
    t <<= 8;
    t += a&0xff;

    a >>= 8;
    t <<= 8;
    t += a&0xff;

    a >>= 8;
    t <<= 8;

    return t + a;
};

Jürgen Eidt http://cpicture.de/en

Interesting topic. I have been searching for month to find a service that can send out registration keys that are not made out of some numbers and letters. No one is able to use a tool provided by the client (that would be the author) to generate the keys. Does someone know a service that can handle this? Jürgen cpicture.de

Thanks for your suggestion. I just wanted to give the icons in my listview a small preview of the AVI files from my camera :) Wouldn't introducing DirectShow to an app make a dependency on the DirectShow components installed on the system? For example I use the latest version of DirectShow but the system has an older version installed? Thanks Jürgen

Does anyone know how to get the first frame of an compressed AVI? Using the AVI-APIs the AVIStreamGetFrameOpen is returning a NULL when the video stream is compressed. Works fine for non compressed videos. I also tried the suggestion from Jung Jinhyuck ( http://www.codeproject.com/audio/avitowmv.asp ) which looked very promising. Looks like the decompression is not done, but the same compressed AVI can be viewed with the Media player on the same machine. Thought the AVI-API could access the same decompressors. (Using WinXP and VC .NET) Thanks Jürgen