[mythtv-users] First Stab at a Shopping List

Rod Smith mythtv at rodsbooks.com
Fri Apr 13 16:18:15 UTC 2007


On Friday 13 April 2007 11:11, David Frascone wrote:
> Rod Smith wrote:
>
> > 2) The 2GHz CPU will most likely be inadequate for HD playback.
>
> I thought the Video card (GS 7300) offloaded a lot of the playback
> issues? 

It does, but probably not enough to get smooth HD playback from a 2GHz CPU. 
XvMC (the software component that interfaces with hardware acceleration in 
some video cards) will help you get HD playback with CPUs in the 3GHz range 
(give or take a bit), but I suspect that 2GHz is just too slow. This is 
assuming we're talking about Intel CPUs, since you specified you've got a 
2GHz "P4" -- presumably you mean Intel Pentium 4. There have been a lot of 
changes in the Intel Pentium 4 line over time, so I don't know what you've 
got or precisely how it compares to my own 3.06GHz Celeron-D 347, which is 
able to play back HD with an nVidia MX4000 or 5200FX video card, but with 
very little CPU speed left over. (Using a 32-bit Linux distribution; it's 
conceivable it would do a bit better with a 64-bit distribution -- or it 
could do worse.) With a (non-XvMC) SiS Xabre video card, my system can't keep 
up with HD playback; it stutters and pauses badly.

> If not -- is 
> there another video card that will work better for FrontEnds?

Not AFAIK. In fact, you could probably go with a cheaper video card. To the 
best of my knowledge, an nVidia 5200FX will give you all the video 
acceleration that's possible, at least in terms of MPEG-2 playback and with 
current Linux drivers. (There's some talk of developing a new acceleration 
library, but that's at least several months away from fruition, if it goes 
anywhere at all.)

> > 3) I've got a pair of pcHDTV HD3000s, and my opinion of them is very low.
> >    Their QAM reception (needed for recording unencrypted digital cable)
> > is very poor for me;
> 
> Well -- Since this is a PoC, I think I'm going to stick with the HD-5500
> for now.  I want to at least scan my cable again, and confirm the
> channels I'm getting.

The problem I see is that you said you want to prove to you wife that this is 
the way to go. If you have problems tuning QAM stations, that won't exactly 
help your case. If cost is an issue, consider this: You quoted a price of 
$129 for the pcHDTV 5500, and that seems about right, though I've not 
verified it. The AVerMedia AVerTVHD A180 is $76 at Amazon and the Hauppauage 
PVR-150 is $56-$80, depending on which package version you get (with or 
without remote, etc.). That makes the total cost of the two-card combination 
$132-$156, or as little as $3 more than a pcHDTV 5500 alone. That gives you 
more flexibility, since you'll be able to record two things simultaneously, 
and when you record NTSC you won't be chewing up ~1GHz of your CPU speed. 
Even aside from my questions about the pcHDTV's QAM reception ability, IMHO 
the two-card configuration is superior, assuming you've got the slots to 
handle two cards.

> When I move on to a true Backend, I think I'll 
> take your advice and go with the HDHomeRun.  When I do that, though,
> should I look for PVR-150s or 250s?

I'm not sure what the practical differences are between the PVR-150 and the 
PVR-250. There are wiki entries on both, so you might find something there. 
Perhaps those in the know could comment with a direct comparison....

-- 
Rod Smith
http://www.rodsbooks.com


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