[mythtv-users] Distortion on sides of video - Overdriving brightness?

Ian Trider iantri at gmail.com
Fri Jul 29 12:28:29 EDT 2005

On 7/29/05, Michael Jones <m_g_j at michaelandholly.com> wrote:
> My system is running svideo from the an nvidia card to a standard 32" tv.
> The video from recorded TV, live TV and from xine is distored along the
> sides of the screen.  I can increase the overscan and eliminate the
> "obvious" edge.. but the distortion is still evident.
> Modifying the overall brightness doesn't seem to help.
> I've also tried changing the resolution, and it still doesn't help.
> It also seems more evident in brighter video than darker video.

By 'distorted' do you mean that straight vertical lines have a
curve/bend in them?

If so this is a likely a flaw in your television set -- you'll see it
if you display certain test patterns on the screen too -- however,
because the output from a PC video card is typically underscanned
(i.e. you can see a border around the edge of the output on the
screen) or just barely overscanned, it might be more obvious -- and
the distortion will increase with brightness since it has to do with
the increased voltage (used to represent brightness) affecting the
components of the CRT (sorry, I'm not an electrical engineer -- I
don't pretend to know exactly how and why).

Do you have a DVD calibration/test pattern disc like Avia Guide to
Home Theater or Video Essentials that you can use to check if it is
your TV set or if there is actually a problem with your card's output?

Ian Trider
iantri at gmail.com

More information about the mythtv-users mailing list