Hi,
I've just stumbled into that: http://coreplayer.corecodec.org/
It looks like the ultimate media player for mobile device devices is going to be released for Symbian today. Apparently, it's gonna support the following formats:
Audio: MP3, AAC, WMA, WAV, OGG, WAVPACK, FLAC, MPC, TTA, AMR, ADPCM, ALaw, MuLaw, Midi
Video: H.264 (AVC), VC-1, MPEG-1, MPEG-4 Part 2(ASP), DivX, XviD, WMV, Theora, Dirac, VP3, MJPEG
Containers: Matroska, TS, 3GPP, MOV, AVI, MPEG-4, NSV
Pictures: JPEG, BMP, GIF, PNG
Subtitles: SMIL, USF