[mythtv] Hardware configuration

[Ray]

On Sun, Jan 05, 2003 at 03:41:14AM -0600, Jesse Crews wrote:
> Forgvive me for beating up a dying horse, if I happen to be. After searching
> the archives, I still have conflicting views on this subject, so I need some
> opinions. Try to reply in paragraphs at the top, as line-by-line responses
> are difficult to read. :)
> 
> I am piecing together a hardware solution, with the following performance
> requirements in mind:
>         - Ability to encode and decode a stream simultaneously (Watch LiveTV
> / active recording) with HQ (~2-3GB/hr) @ 704x480 or 640x480
>         - Ability to encode/decode simultaneously without dropping frames
> with HQ.
> Harware planned: (This configuration <$400 w/o HDD). (current) means
> hardware is already here.
>         -Hauppauge Bt868 card (WinTV w/ dbx stereo) (recycle)
>         -Athlon XP 2100+ (cheap and can be scaled down to reduce excess
> overhead and heat)
>         -Asus A7S333 (SiS745) - inexpensive with decent performance (~10% <
> KT333). OR AMD 761 based MSI 6341 OR KT3-Ultra2-C
>         -Samsung PC2700 @ 128MB, assuming the task is CPU intensive, with
> minimal memory requirements.
>         -IBM 180GXP @ 120GB + 8MB cache
>         -Yamaha YMF-754 audiocard (Hoontech SoundTrack Digital GX + Digital
> I/O) (current)
>         -Geforce2 MX200 for VGA/SVHS output. Possible future HD (projection)
> here.
>         -Some desktop shape case to match the other equipment
>         -Generica IR receiver + Sony RM-AV2100 + LIRC (current, working)
>         -Hollywood plus card, possibly used if DVD quality of the GF2 is not
> (as) good. <--- use external application :) (current)
> 
>          dist - Gentoo or Debian (currently running in Gentoo w/o tuner
> quite flawlessly) I prefer Gentoo because sysapps are latest, and Portage
> avoids ickyness accociated with manually downloading/configuring/installing
> sources.
> 
> Questions:
> How much overhead would there be? How many extra streams can be handled at
> the same time as CODECing one (translation: What's the lowest speed CPU we
> can get away with)?

I'm not sure what the minimum would be but your above specs look fine.  The
Athlon 2100 looks like the the sweet spot in pricing for Athlons right now. 
A lower end Athlon should work but an application like Myth is going to
uncover any problems in  your system.

> 
> Are there any known issues with this chipset? Is DDR memory really
> necessary? How much data is moved at any given time through the system bus?
> Ability to reliably record @NTSC HQ is important. Do practical tests show
> scaling effects when comparing = CPU and != memory controllers (ie.: SDR vs.
> DDR133 vs. DDR166...)?
> 
> Important -- Use cheap SiS or VIA? Which is more stable? KT333 is clearly
> better performer, but does this matter here?

I've been using various SiS based boards in most of the machines I've built
for the past year or so and have been very happy with them.  I think the PCI
latency bugs have been worked out of the VIA based boards but I'd still go
with SiS personally.  You might also look at some of the Nforce2 based
boards.  They are new enough that you might have to fetch updated drivers or
whatever but they look very promising.  If you go with an SiS 735 based
board you could try both SDRAM and DDR and tell us how much performance
difference there is since right now everyone is just guessing.


> Software:
> We should encode @ 29.97 FPS (NTSC). Are there any isssues here? I'm leaning
> toward MPEG4 at the moment.

This stuff is built into Myth so try both mpeg4 and rtjpeg and see what you
like best.  The system above should have plenty of power to do either one.

-- 
Ray