[mythtv] openbrick / frontend [MHz fuzz]
hpoley at dds.nl
Fri Jan 24 19:39:47 EST 2003
Please: CPUx MHz != CPUy MHz
And there's more to say...
"To keep a long story short, my 930Mhz Via EPIA M can just barely be a
mythfrontend. No matter how good the geode is, at 300Mhz I don't think it
will work too well."
As stated above, but indeed, in the readme of DivX you'll see that you need
a '400MHz processor'. And that's not entierly vapor, at that many clocks
(with an 32bit processor) you have the kind of throughput to sustain video.
But lower MHz should always be possible.
Just as a sidenote. The current OpenBrick indeed can't playback video at a
rate you would like. But they are working on it's successors (including
ones with decent video capabilities). Please visit the website OpenBrick
and vote for one you like :-)
: In response to 
"hmm this wonders me... me 600mhz laptop has only 30% cpu usage with
mythfrontend running, rtjpeg is set to 400x400 with quality 170..."
As above, plus: 600 mili herz? :-P
btw, what processor?
: In response to 
"Hmm... You sure you've got everything set correctly? My 1.2GHz Duron on a
Via chipset, Epox 8k7a2(something like that) fell _just_ short of being
able to encode and decode 640x480 mpeg 4 at the same time."
Not only does VIA make motherboard chipset, they also make processors. VIA
bought the technology from Cyrix. That's why it's called VIA C3, aka VIA
Cyrix III. There are currently 2 flavours, the Eden and the Ezra. Both are
more or less the same but differ in bits like L2 cache structure, and are
direct decendants of the original Cyrix III. Key features are low power
usage and heat dissapation. View the datasheets if you would want to know
the exact stuff, they are written in a quite readable manner.
: In response to (?)
"The EPIA 800 was clocked at Tom's Hardware as being hideously slow,
something around a 400 MHz PII, and much much worse on multimedia (like
encoding mp3s, it took twice as long as a PII 400). So, bumping it up only
133MHz, I don't see it performing that much better. Don't see 933MHz and
think that a GHz computer would work fine. The only way this one would work
ok is if the stream was MPEG2, since it has an on board decoding chip."
As always, there are benchmarks and there are benchmarks. If you would ran
some Win9x app on a Sparc (yes, that would be in an emulator) you could say
that those processors are just crap.
Then you probably ask why I would drag 'emulation' to this... Well x86
floating point is emulated on the C3 (via microcode, with interger
calculations). AFAIK 3Dnow! and MMX are executed natively by the C3 (not
emulated). The benchmarks which tell you that everything works just as
expected (though a bit slower than a PII-800) have used a codec that's
optimized to take advantage of this. For example try running Windows Media
Player on a C3 and it will have severe hickups, use anthing else and it
will almost always work. That's probably caused by some filter that is used
in post-processing by MS MP.
[NB: I don't speak from experience, this is just what I've read here and
there on the internet. Plus there are non-hardware-MPEG2/MJPEG PVR's that
use the VIA EPIA M9000 motherboard]
Henk Poley <><
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