I want to reduce my game size by convert my wavs to ADPCM based, but before this I got some question, could you help sort them out, thanks in advance. 1.There''re 2 ADPCM format: IMA and MicroSoft, what should I choose? 2.I''m using FMOD as sound engine, can FMOD handle ADPCM on all Win32 OSes? Or the ADPCM support requires a particular codec?

It should work, however I didn''t get a reason why you don''t use regular PCM as today''s PC has great storage capabilities, and your "saving" on sounds can''t be enough.
And yes, FMOD can read tham