From Forum Nokia Wiki

• Helix Player is a open sourced multi media player. This version has support for 3GPP rel5 SMIL, RealAudio, RealVideo, MP3, MP4A, H263+, AMR NB/WB, images and other datatypes. you can download the precompiled binaries (in SIS form) or to download the source code and build the player yourself.

Now Helix Player is working on S60 3rd edition !