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

Michael Jones m_g_j at michaelandholly.com
Sat Jul 30 00:59:12 EDT 2005

I had a feeling that might be the case..

Is there a way to allow the signal from the computer to the TV to have (or
show?) more of the overscan.

My TV doesn't seem to have the problem when displaying the MythTV GUI or KDE
(that I can tell). I also don't see the distortion when I play a DVD from my
regular Panasonic DVD player.

I don't have a test/calibration DVD.. So I have no way to verify the TV

I wonder if this could this be related to the SVIDEO output from the Nvidia
card (with the testing driver) or even the cable I'm using?

- Michael

> From: Ian Trider <iantri at gmail.com>
> Reply-To: Discussion about mythtv <mythtv-users at mythtv.org>
> Date: Fri, 29 Jul 2005 12:28:29 -0400
> To: Discussion about mythtv <mythtv-users at mythtv.org>
> Subject: Re: [mythtv-users] Distortion on sides of video - Overdriving
> brightness?
> 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
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