johns said:
Has anybody invented a PCI-e card that will give HDMI output ?
Or is there a video card that will do it ?
Or, is there a connector DVI-music hack for it ?
All the new 16:9 TVs and monitors have AGP only, and
yet there are HDMI splitters on the market in lots of game
stores. I'm assuming that HDMI is digital graphics and
thus better quality than AGP .. I may be wrong there, but
I simply don't know.
johns
http://en.wikipedia.org/wiki/Vga
http://en.wikipedia.org/wiki/Digital_Visual_Interface
http://en.wikipedia.org/wiki/Hdmi
If you look at the pinout for HDMI, it uses the same kind of
signal names as DVI. And in fact, there are DVI to HDMI and
HDMI to DVI dongles. You can find video cards with HDMI on
the faceplate, and also find video cards that include
a dongle.
Pin 1 TMDS Data2+ \
Pin 3 TMDS Data2– \
Pin 4 TMDS Data1+ \___ RGB at 10x the clock rate
Pin 6 TMDS Data1– /
Pin 7 TMDS Data0+ /
Pin 9 TMDS Data0– /
Pin 10 TMDS Clock+ \___ Clock (165MHz DVI max, HDMI goes faster)
Pin 12 TMDS Clock– /
HDMI incorporates HDCP (whereas with DVI it is optional and
something you have to check for). HDMI also has the ability to
carry audio. Dongle conversion of DVI to HDMI, is a connector
format conversion, and does not magically add anything else.
The dongle made version, is not the same as the real thing.
(As the real thing can have a higher clock rate, allowing
higher resolution settings.)
Digital is, well, digital. As long as the logic 1's and 0's
arrive in one piece, there is no loss in signal quality on the
cable. If you make the cable too long, for the clock rate being
used, then "snow" shows up on the screen. And that is bit error
rate, becoming evident. So digital does have potential degradation,
if you attempt to use a crappy (high loss) cable, or stretch ordinary
cables for too many meters.
At high resolution, the advantage of DVI/HDMI becomes more obvious.
VGA, being analog, means every reflection and imperfection in the
signal, could be visible on the screen. Like if you were trying to
send 1920x1200 over VGA, chances are there would be a shadow or
ghosting in the image seen on the screen. Digital transmission
could very well deliver the signal in perfect condition. If
you were operating as 1280x1024, then it is harder to see a
difference.
Paul
