Hi all,

Below is my specification for a new MythTV box. Please check the hardware over and help me head-off any problems. With some pieces of hardware I gave an explanation as to why I picked it. This system must be able to handle recording one HD channel with being able to watch/pause another.

$85 GA-K8NS-939 getting this for the CnQ, AGP, SATA, 1000 Ethernet, 939, nvidia chipset, no on board fan)
AMD SEMPRON 939 socket 3000+
1GB RAM (2 512MB DDR400 184PIN DIMM )
HD3000 (Starting with one will have 2 eventually)
Adesso WKB-4000US (wireless keyboard with touchpad)
2 160GB SATA Seagate Barracuda V's
MSI Nx6200ax-td128 video card (component out, no fan, hardware mpeg decoding)
Cooler Master Cavalier 2 - 350W PS (Went for the 350W because the 300 looked like it was just cutting it too close)
BenQ DW1640 (heard it is quiet)
Chaintech AV170 (for the 8 channels and optical out)
Home Electronics IRA-3 (No reason, just found it)

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GA-K8NS-939 Ultra
AMD 64 939 Venice 3200+
1GB RAM (2 512MB DDR400 184PIN DIMM )
HD3000
2 160GB SATA Seagate Barracuda 7200.7s
MSI Nx6200ax-td128 video card
Cooler Master Cavalier 2 - 350W PS
BenQ DW1640

Thanks,

Chris Lopeman

I suspect my Athlon 64 3200+ is right on the edge of what you can get away with for HDTV. I know that when I was experimenting with the HD-3000 (before giving up temporarily due to signal quality and antenna issues - bad line off sight and lots of sources of interference) it was working plenty hard to decode WGBHDT...

An Athlon 64 3000+ would be pushing it, and a Sempron ...

THanks for the response.

This is interesting and confusing. In another forum I have somebody telling me that I have speced far too much power. Here just the oposite. WIth your attempts, did you have an nVidia card with hardware decoding?

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GA-K8NS-939 Ultra
AMD 64 939 Venice 3200+
1GB RAM (2 512MB DDR400 184PIN DIMM )
HD3000
2 160GB SATA Seagate Barracuda 7200.7s
MSI Nx6200ax-td128 video card
Cooler Master Cavalier 2 - 350W PS
BenQ DW1640

Thanks,

Chris Lopeman

until VERY recently attempting to use nvidia with hardware decoding resulted in frequent lockups.

I'm still not convinced enough to say xvmc is ready for prime time.

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Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

Yeah, what Xsecrets said. XvMC is more trouble than it's worth. I wanted the system to be reliable rather than frustrating, so I threw a little bit of extra cash at the problem.

I've wasted enough of my life engineering around inadequate hardware because someone else was paying me to do it. The lesson that it burned into my memory is that it's dumb as a box of rocks to save $500 on hardware at the cost of $20,000 of engineering time. Heck, even MBAs can learn that if you hit them over the head with the numbers hard enough... And I'm not talking about the type of costs you can make up on volume either.

Well previous everbody was telling me that I would have to use XvMC too actually do HDTV to the extent I want. Also the lighter processor should keep the heat down. Since your both recommending staying away from XvMC and burdoning the processor, what processor are you recommending? Sempron 3400+?

And I should ask, are you both doing HDTV and what processors do you use?

_________________
GA-K8NS-939 Ultra
AMD 64 939 Venice 3200+
1GB RAM (2 512MB DDR400 184PIN DIMM )
HD3000
2 160GB SATA Seagate Barracuda 7200.7s
MSI Nx6200ax-td128 video card
Cooler Master Cavalier 2 - 350W PS
BenQ DW1640

Thanks,

Chris Lopeman

I wanted to point out that Dragon uses an Athlon 64 3200+ and an nVidia 6200 TurboCache card. Using libmpeg2 for playback works great. 480p uses ~30% CPU, 720p uses ~75% CPU, and 1080i uses ~62% CPU. It's more for 720p, even though it's lower resolution, but progressive scan vs. interlaced is probably the reason for that higher usage.

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KnoppMyth R5.5
MythiC Dragon v2.0
Join the KnoppMyth Frappr!

75-85% is what I remember for WGBHDT (presumably 1080i), but the system was also scaling that to display on a SDTV at 800x600. Happily the Athlon 64 (Venice core) never lost it's cool and stayed under 106F/41C. The Zalman CNPS7000B-AlCu probably had something to do with that too...

If you ever want to be sure what resolution a show is, just run mplayer on it and it will output this as part of its standard diagnostics. Of course, sometimes stations upconvert even 480i/p programming to 1080i, so the video you watch may just be a small chunk of the overall transmitted video size.

In my tests, though, I didn't notice any difference in CPU usage of upconverted 480->1080 programming vs. native 1080i programming.



Hmm. So your X display was your TV, with the resolution set to 800x600? Did you ever do any CPU load tests where you tried transcoded content at 800x600 vs. the scaled 1080i content? Just wondering roughly how much CPU is eaten up by mismatches between monitor resolution and video resolution.

_________________
KnoppMyth R5.5
MythiC Dragon v2.0
Join the KnoppMyth Frappr!

No idea, it was partly feasibility testing, figuring that if it worked scaled it'd work even better at native resolution.

My signal quality problems (bad line of sight and unspeakable amounts of RF noise, partly due to a 25-30 meter tall taxi company antenna ~100 meters from the house and 180 degrees from the HDTV tower) curtailed further experiments. I either need a really primo antenna or a working QAM feed.

This has been very useful information. I guess I would be in the ~75% area, since I am interested mainly in 720P. Assuming recording takes less than ~10% per channel, this would max out the processor. Dragon has a pretty powerful processor, and I noticed the same processor being used by a poster in this thread. I was trying to stay with the sempron family to keep the heat/noise down. Depending on the application the sempron can perform just as well as the Athalon 64. But I am not sure this is one of those applications. Has anybody tried any HD playback load tests with a sompron using software decoding?

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GA-K8NS-939 Ultra
AMD 64 939 Venice 3200+
1GB RAM (2 512MB DDR400 184PIN DIMM )
HD3000
2 160GB SATA Seagate Barracuda 7200.7s
MSI Nx6200ax-td128 video card
Cooler Master Cavalier 2 - 350W PS
BenQ DW1640

Thanks,

Chris Lopeman

you got your ira-3 device working properly ?
there is couple guys in deep trouble with that device.
Topic 12610

Not sure why your going with the socket 939 platform? I see no reason to buy new hardware on a dead platform. I'm highly recommend going with a socket AM2 Geforce 6150 based motherboard. While the board and chip may cost a little more it saves you from having to buy a video card. The integrated GeForce 6150 graphics are perfectly adequate for HDTV with Myth. Of course you can alway add a more powerful card later if you desire.

I wouldn't go anything less than a 3200+ on the processor. I personally decided it was worth the extra ~$30 to go dual core and never have to worry about not having enough power.

For the remote I highly recommend you get a streamzap. It's stupid easy to set up and you can always upgrade to a fancy remote like a Logitech Harmony later on and it will work perfectly with the Streamzap IR receiver.

Before you buy, take the time to look through the Tier 1 hardware section and see what others are using and having good luck with. tjc hit the nail on the head, it's better to pay a few bucks more for stuff that "just works" than to spend all your time trying to kludge something together only to end up with an unstable system.

Martian

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ABIT NF-M2 nView | Athlon 64 X2 3800+ | 2GB DDR2 800 | HDHomerun | GeForce 6150 (onboard) | WD 640 GB SATA HD | DVD-RW (sata) | StreamZap IR receiver with Logitech Harmony remote

Vizio 37" LCD HDTV (1080p)

Be careful with the time-travel, dude.
People from 2005 know not of what you speak, and they were doing the best they could, with what they had. Dual Core? Crystalic Fusion? Plasma Rifle? They could only dream.

Don't forget, it's always possible to add on borg technology to the dead platform and breathe new life into it. Sure, you run the risk of your computer assimilating you, but that rarely happens.