search for: vorbisfloat

I saw some mail go by a bit ago about doubles-vs-floats, but I seem to have lost it. I'm interested in rewriting the mdct code using Altivec on MacOS X. Altivec doesn't support doubles, though -- the only floating point vector type is single precision floats. Vorbis currently has doubles everywhere -- is this really necessary? Doubles are supposedly faster than floats in the PPC