Media player/recorder (phonon)

Question

I would like to develop a media player/recorder.

The primary target platform is Windows, support for other OSs would be nice, but that's not a high priority. It should be able to play formats like wav, mp3, avi. It should also be able to record audio (microphone) and video (webcam or capture card).

As I have some experience with QT and C++, I looked at QT (4.7.2) phonon with DS backend. But unfortunately I was unable to play a simple AVI, even with the MediaPlayer sample that comes with the QT demos. I could only hear sound, but saw no video.

The developer machine is a 64-bit Vista. I also tried it on another 64-bit Vista without any luck. On a 32-bit Win7 (QT MinGW) it then finally worked. But when I copied that MediaPlayer executable and its dlls to the 64bit machines and tried to run it, it again failed.

Is there a known problem with QT phonon on 64 bit machines? I also heard of a VLC phonon backend. Could that be solution? Is QT phonon mature enough to develop a commercial application on top of it? Or is it maybe more wise to access directshow directly?

Thanks

Answer 1

Directshow is just a programming framework or API, it does not guarantee that you will be able to play every possible video format on every computer, since it relies on codecs installed on the system to decompress the audio/video streams. A codec for one specific format might be available in one system an not in anotherone. On top of that, 64 bits architecture adds even more complexity, since codecs built in 64 bits mode cannot be used from 32 bits applications and vice-versa. The issue you are facing on the 32 bits Phonon player is very likelly to be caused by a missing or "not 32 bits compatible" codec.
VLC on the other hand is a self contained application, it does not depend on DirectShow or in any codec installed on the system, so it might be a good idea to use it instead of DirectShow, however you will need to read VLC legal terms and decide if you can still use it for your purposes.