[mythtv-users] Video Card Suggestions for DVI/HDMI Output

[Michael T. Dean]

Chad wrote:

>On 6/28/05, Jon Kunze <jon99ut at gmail.com> wrote:
>  
>
>>I recently purchased a Toshiba 52" DLP television, and I'm now
>>interested in upgrading the quality of the MythTV Display. I'm
>>currently using the Svideo out on my Chaintech mother board with the
>>nividia mx440 on board. I would like to use either the HDMI or
>>component input on my new television.
>>
>>What would be the suggestion for doing this output. Would it be
>>beneficial to use the HDMI input as opposed to the Component input?
>>
>>If I use the HDMI input, what would be a good video card to purchase
>>that is compatible with the HDMI input (I'm assuming that I would want
>>to get a video card with DVI output and use a converter to HDMI).
>>
>>Any suggestions would be greatly appreciated, as I'm soon going to be
>>recording and displaying HD recordings, as well as want the upscaling
>>of the DVD video. Thank you.
>>
>There was a thread a while back with a link to an article on DVI vs
>HDMI vs Component.  The jist, it really doesn't matter.  Whatever is
>cheapest and most available,
>
--as long as it has good impedance characteristics--

> that's the one to choose.
>  
>
Article is at http://forum.ecoustics.com/bbs/messages/34579/122868.html 
.  It basically says you won't know which is better until you try both 
on /your/ equipment (and you may have different results with different 
components).

>I also read a bit on HDMI, and it sounds like that is the least likely
>choice you want to make.  It's nice to have 1 small/single cable to
>run dvi quality with audio, but there were some pitfalls that I can't
>remember right now.
>  
>
HDMI = DVI + HDCP (High-bandwidth Digital Content Protection (often 
called High Definition Content Protection) = Digital Rights Management = 
if the broadcast flag goes through, something Linux will never be able 
to support).

Also, HDMI cable is typically thinner than DVI.  This means that HDMI 
cable is more likely to cause bit errors than DVI (i.e. a particular 
HDMI cable might not work with your setup, but DVI cables are far more 
likely to work properly, so with DVI, you're less likely to have to do 
returns/exchanges).

And, the signal transmission format used by DVI and HDMI (TMDS = 
Transmission Minimized Differential Signaling) is based around SDI 
(Serial Digital Interface), which was designed for coaxial cables.  
However, the designers of DVI/HDMI decided not to use coaxial cables and 
instead use balanced, twisted-pair cables--which are significantly less 
capable of controlling impedance.  This can cause bit errors, and--since 
DVI/HDMI do not provide for error correction--display problems.

Component uses and was designed for coaxial cable.  In some cases, 
component may problems with the black level.  If your TV allows for 
correction of black level, this won't be a problem, but if not, you may 
be stuck with the same "NTSC purple-black" that we've had for 50 years.  ;)

Regardless, either approach you take will be so much better than S-Video 
that you'll love the results (even if there is a minor improvement in 
quality possible using the other solution).  Basically, think of it as 
upgrading from a Pentium II @ 400MHz to a Pentium 4 @ 2GHz versus a 
Pentium 4 @ 2.13GHz.  The change will be so dramatic that you will be 
happy with the results, and you're unlikely to notice the difference 
between the two P4's unless you really look for the difference.

HTH.

Mike