[mythtv-users] Re: Hardware questions

[Jarod C. Wilson]

On Tuesday, Keith C responded to what Reid Peryam wrote:

>> 2. How good of a sound card should I buy? I was thinking of going
>> cheap, but then I was thinking that if the entire signal is going to 
>> be
>> coming from the computer to the television, I should probably have
>> something that can sound pretty good (6-channel for option of 
>> speakers).
>
> Look at how you'll be moving the sound to your stereo system.  Got a
> digital input into your amp?  Find a compatible digital out on a sound
> card that works with Alsa. You get the picture - figure out how you're
> going to hook it up and buy a card that matches.

Personally, I stick to mostly Creative cards. That, and M-Audio, when 
going high-end. I got an Audigy OEM for about $40, and it works 
perfectly with ALSA, feeding a signal to my amp via S/PDIF. There are 
some issues with certain Creative cards on some older motherboards 
though, but I can't recall which specifically right now. I believe it 
is either KT133 or KT266-based systems, but my KM266-based system has 
no problems whatsoever. (Nor does my AMD 760-MPX-based system).

>> 3. Is a video card important at all? The encoder will probably be
>> pushing all of the bits, I'm thinking. I was thinking of going with 
>> two
>> separate cards, a video card and separate PCI TV tuner. If Graphics
>> aren't at all important then I'm thinking that an AGP 4x/8x 
>> motherboard
>> isn't needed?
>
> Not that important.  The Geforce4 MX 440 is popular here because of the
> clean TV out signal and good linux support.  I've got a Geforce4 Ti
> 4400, and it works great, but it is not worked very hard at all by
> MythTV.

The GeForce 4 MX 440 seems to be the de facto standard (outside of 
those systems w/built-in video)... It works quite well for me, and the 
TV out signal is indeed very good (excellent quality on my HDTV).

>> 4. Is the TV tuner important at all? It seems as though all you need 
>> it
>> for is the coaxial line-in port. Any other things I should look for
>> when buying it or is bare bones good enough?
>>
> Answer is same as #1, really.  If you want to offload, get the PVR
> card.  If you want to use processor muscle, get the cheaper card.  The
> PVR is a little limiting because the output is always MPEG2, but the 
> new
> transcoding option in MythTV gives you options for reencoding to save
> space or use the files in other apps.

I've got both a PVR-250 and a bt878-based card (AVerTV Studio). I like 
the PVR-250 far better.

>> 5. Hard Drive. The website says about 2 gigabytes/hour while 
>> recording.
>> For some reason this seems really low to me. Is that for a smaller
>> resolution? So the drives are all pretty cheap, but what I'm thinking
>> of is that if I had a 10,000 RPM drive (¡Á 7,200) fast forwarding and
>> track marks would respond *much* faster. There is a huge price
>> difference though and the max capacity for a 10,000 RPM drive is only
>> 36 megabytes. Maybe one 10,000 rpm drive for main usage and a residual
>> 7,200 drive for spill over? I doubt I'd be recording more than 10 
>> hours
>> at a time (length of two football games), even over vacations. Any
>> thoughts?
>>
> Not sure how much speed difference you would notice with a faster
> spinning drive. The cache is important, I'm sure, as well as the 
> overall
> back plane speed.  36MB is pretty skimpy once you get your whole system
> built, especially if you put any music on there at all.

I assume you actually meant 36GB, but there are most definitely drives 
larger than 36GB at 10,000 RPM. They just cost a ton. If you're talking 
36GB drive, that means you're also talking SCSI. For the record, my 
dual Athlon test system has three 36GB 10,000rpm drives in it with an 
Adaptec 2100S Ultra160 hardware SCSI RAID card (128MB cache), set up as 
a RAID-0 array. There is next to no difference in playback quality and 
responsiveness between it, and my primary, production MythTV box, which 
has a single 7200rpm ATA/100 drive.

>> 6. Linux. I've never done a thing in Linux but have experience in
>> UNIX... anyway I'm hoping to learn. Also -- Red Hat, Madrake, Debian
>> etc. -- which is right? MythTV seems to suggest that Red Hat has a
>> bunch of settings that are naturally in conflict with it that need to
>> be modded, yet Red Hat seems to be the most popular version. I was
>> gunning to install the barest of Linux OSs on this computer as I'm not
>> using it for anything except TiVoing, MP3s, and maybe a few games.
>>
> I tried Debian, and although I was impressed with it and the power it
> gave me, I was not enough of a Linux expert to make it work (close, but
> not quite).  Redhat 9 was easy for a single reason : Jarod's guide.
> http://pvrhw.goldfish.org/tiki-page.php?pageName=rh9pvr250#apt

:)

>> 7. Is more than 256 RAM worth it?
>>
> For the cost of it, I'd never build a system with less than 512, but if
> this is solely a MythTV box, I don't think you need more than 256.

I second that. Get more. It's cheap, and worth it in my view. I've 
heard some people say they get a bit of swapping with only 256, while 
384 eliminated all swapping. I use 512MB myself.

>> 8. Will I be able to record two separate channels at the same time? If
>> so do you think I should dual process it? What other components will 
>> be
>> affected?
>>
> Check the PVR answer again :)  With tuner-only cards, you'll need about
> 1 GHz per stream.  With PVR cards doing their own encoding, stick as
> many as want in it.  You'll need a tuner card per stream as well, of
> course.

Dual processors is overkill (unless we're talking slow dual procs, like 
a pair of PII-450s). I certainly wouldn't waste money on a dual 
processor system for a MythTV box. (Yes, my test system is a dual 
Athlon 2000, but I use it for far more than just MythTV 99% of the 
time). Read here:

http://mythtv.org/docs/mythtv-HOWTO-3.html#ss3.1

I still need to get around to testing it out, but I believe my Athlon 
XP 1700 production system will have no problem w/both the PVR-250 and 
AVerTV Studio cards in it, capturing two channels and playing one back, 
all at the same time. (I may eat my words when I actually test it out; 
I'll let everyone know!)

>> This is so much more expensive than buying a TiVo but it's going to be
>> a lot more fun!
>>
> It has been fun.

No doubt!

--Jarod

-- 
Jarod C. Wilson, RHCE

Got a question? Read this first...
http://catb.org/~esr/faqs/smart-questions.html

MythTV, Red Hat Linux 9 & ATrpms documentation:
http://pvrhw.goldfish.org/tiki-page.php?pageName=rh9pvr250