On 15 Oct, this message from Derrik Pates echoed through cyberspace: > On 16 Oct 2001, Michel D�nzer wrote: > >> Even with Linux, the choice isn't so hard, with a growing amount of >> software supporting Altivec. In particular, watching DVDs is certainly >> much more of a pleasure on a TiBook now than it will probably ever be on >> a G3 Notebook. > > Are there any asm optimizations that can be done for speeding up MPEG-2 > decoding on a G3? Or is Altivec (and therefore a G4 PowerBook) the only > answer?
The single best thing to do on a G3 is using whatever hardware decoding support that is available in the graphics chipset. How muuch can be gained by using hand-tuned asm depends on the compiler quality (scheduling multiply-add instructions from 'simpler' C code) and on the know-how of the asm coder. But in my opinion you need a _lot_ of experience and know-how to write optimized asm. > Where's the big performance optimization on MacOS for DVD > playback? Is it using the ATI chips' hardware iDCT capability, or asm > optimization, or something else? It's using the ATI chip for IDCT, MotionCompensation and colorspace conversion. When doing it entirely in software, the G4/400 is about the minimum processor level you need to decode full framerate, but still using the ATI's colorspace conversion to do YUV -> RGB in hardware (which we know how to do in XFree 4). Cheers Michel ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email [EMAIL PROTECTED] | http://www.cpu.lu/~mlan | Learn Always. "
