Xbitlabs did some measurements on how much cpu it takes to
play video.
http://xbitlabs.com/articles/video/display/video-playback.html
Of course they did this with binary drivers for virus-server.
And they didn't hunt down high bitrate sources. Or tell us
what the bitrate of the sources is. And they used a x2 "FX"
(expensive) cpu. Some of the tests would have failed using a
more normal cpu, much less a low end one, or an older model.
They do provide some maximum bitrates:
DVD mpeg2 max bitrate approx 10 Mbps
mpeg2 HD up to 80Mbps
mpeg4 - DivX HD capabilities are formally limited to 1280x720 resolution
at 30fps and a bit-rate of 20Mbps. [ seems odd ]
MPEG-4 AVC/H.264 - up to 40Mbps HD-DVD and Blu_Ray
H.264 takes 2-3 times as much cpu as mpeg2. (for whatever bitrate
sources they used)
A "rather low bit-rate" H.264 would nearly max out a single FX cpu.
So a higher bit-rate H.264 would fail on a single cpu, even with a
"premium" graphics card. Forget using a normal cpu, much less a low
end or older model. With an "entry level" card, their "rather low
bit-rate" H.264 needed 67.2% of the x2 FX cpu. A high bit rate
H.264 might well fail even with their x2 FX cpu.
Questions:
How much hw assist are these graphics cards providing? I get the
impression that ATI and Nvidia concentrate on gaming, perhaps we
can beat them at video decoding?
How much cpu is it acceptable to require? CPUs have other
things to do besides decoding video, so using 100% of the cpu
is not going to work. Is it really acceptable to require a
high end x2 FX cpu?
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