Tim Schoenfelder wrote:
Hi,
A friend (Its never the person writing the email right ;) ) is looking
for a videocard that will display at variable screen resolutions (
640x480, 800x600, 1040x780 etc) to regular NTSC TV Out (480i S-Video
preferred interconnection) in such a way that would allow readable
text on the TV.
For instance, his ATI Radeon 9700 while displaying to TV output would
not render readable text on his TV and it would not allow him to
adjust the screen resolution. You can barely read it (Please correct
this statement if he was using the card incorrectly..he was using the
S-Video Output on it). You know that its there, you know where you're
going so-to-speak but you can't see "squat". The reason for the text
is to not have to have a monitor on top of the TV cluttering up the
living room.
Any ideas as to what types of card(s) if any would solve this
problem? (Links are welcome)
BTW, this card would be a solution to displaying Divx, Xvid type
movies as played on a PC onto his TV as well as to eventually migrate
the PC into a PVR system down the road ( eventually upgrading to HD
). Hopefully not too tall of an order...
Sincerely,
Tim Schoenfelder
Hello Tim,
I'm afraid that there's only a limited room for improvement on this
unless your friend has a HDTV, which I doubt. The fundamental problem
here is that a TV has a fixed frequency and resolution and regardless of
what resolution the VGA card might be running, the resulting signal
*must* adhere to this standard, and so gets converted on the way. For
NTSC televisions, this locked in stone resolution is 480 rasterlines
with 640 square pixels in each, updating at 2x30 Hz, or 640x480@60. It's
not coincidental that this is the same as the "VGA" resolution which was
standard for several years back in the early 90ies - it was based on the
TV resolution. If you wish to display content on a TV, this is the
resolution you should be using, as there's no resizing involved and so
no loss of information. It is indeed possible to run both 800x600 and
1024x768, but all you achieve is that the signal is being sampled down
on the way to the TV, and all text will look blurred since the
resolutions aren't divisible by each other (1024/640 is not an integer
number).
Of course, the explanation above does not account for overscan - other
people can explain this better than me, suffice it to say that when you
count all the lines that are outside of the visible screen as well you
get 512 lines (I believe) and this corresponds to 'broadcast'
resolution, where the picture has to be guaranteed to cover the entire
screen.
So in conclusion, there really is nothing to do about the TV resolution
except either buy an HDTV or a projector.
Cheers,
Ole
