Agreed, the coercion in Initialize() forces us to reinit the sink when the requested format is different from the current one, even though after init they will be the same.  Play back MP3 without this patch and you get a blip of silence between each track due to the sink restarting since AE queries us with AE_FMT_FLOAT instead of AE_FMT_S16LE.

I'd be happy to generalize the sink for more working formats once Google gets the implementation details straight.