Qt Multimedia/Mobility vs. Phonon: FIGHT!!!
Well it's not really like that, but I guess those involved can think about it a bit like that at times!. For some background, Phonon is a Multimedia framework that was included in Qt 4 as far as I understand it, it was developed outside Qt, but was adopted (please correct me if my history is incorrect here). It was designed to give application developers easy access to media playback systems, be it MP3 music or new fangled WebM video! Rather than implement any of the complex stuff itself, Phonon hands off the actual decoding and playback parts to existing media frameworks. Originally Qt wrote a GStreamer "backend" for Phonon and this was the only available backend on Linux in the early stages (others were available for other platforms too). I personally think that GStreamer was a good choice. I think it is a very powerful system, but it's not for the feint hearted. I wont begin to pretend that I understand it (although I have hacked my way through some GST code!), but the principle of it's operation seemed to fit the needs of the Phonon project very nicely.