How can you get a list of file extensions for video formats that a given system can read?

[TwoGunBerg]

Hi All;
I have a media player that i have written which uses phonon. Right now i have a hard coded list of formats that i allow for video and audio playback. I just noticed the "BackendCapabilities::availableMimeTypes()" method which gives me back a list of mime types available on the given system. Is there a way supplied by Qt of converting this list to a list of file extensions? For the momen we are still using Qt 4.7.1 on VS2008 for the windows platform

[andre]

Why would you think there is a 1:1 mapping between file extensions and video formats? Most of the file extensions in use are just container formats, that can contain many different types of video formats that you may or may not have the right codec for.