1. SUPER (C)
It can convert Audio/videos to many formats including rare MMF (Yamaha's SMAF mobile format, but i haven't tested it). AMR, 3GP, common audio and videos formats like FLV, SWF, AVI, formats for portable devices like IPhone, BlueRay, Nintendo DS (DPG), etc.
2. Extreme Sample Converter
It can convert to almost all console, mobile, DLS, SF2 sound fonts, VSTi, AKAI, FLAC, YAMAHA etc containers. I converted Microsoft Windows (actually Roland) "General Midi DLS", gm.dls to gm.sf2, SoundFont and using in Midi Synthesis.