On Fri, 24 Aug 2001, Adam Goode wrote:
> On Fri, Aug 24, 2001 at 04:45:45PM -0700, Peter Meilstrup wrote: > > > > Now, I think you need around 500 floating point-operations to compute an > > 8x8 IDCT (I believe the actual figure is something like this.). DVD video is > > 720x576, so you'd need to sustain around 100 megaflops/sec in the IDCT > > alone to be able to play video smoothly. Based on that figure, I think > > software-only decoding *might* possible on a 500 Mhz g3, but it'd have to > > be pretty tightly optimized. It'd be nice if ATI would release > > documentation on the hardware IDCT and motion comp features of the Rage > > 128 chip... > > > > Are you sure? Because things seem to play pretty well on my 400 MHz iMac. The 500 flops figure is based on assuming it takes half as long as the simplest implementation of an FFT. There might be better implementations of the algorithm however. Define "pretty well" and what environment you're running in... under linux the best I can get is very noticeably jerky on my 500Mhz Ibook2. Under MacOS the DVD player software uses the ATI card to to the grunt work. --Peter
