[mythtv] Hardware configuration

[Jesse Crews]

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)?

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?
MSI KT-3 Ultras are also inexpensive. Stable? Was PCI fixed since KT266a?
Proper mainboard selection is important here. Archives report KT266(a) has
broken PCI.
I suspect GF2MX should work with the nvidia TV-out tuning software for
Linux. It is also inexpensive at ~$35 US.

What is the SVHS output quality (when tuned for proper overscan, etc)
compared against something like an EM8300 (DXR3/Hollywood) when playing
video (possible DVD addition here)?

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


I would appreciate any comments relevant to this information. I would like
to optimally configure the system for cost and performance.

Regards,
Jesse