[mythtv-users] Computer can't read EDID from Panasonic TC-P42C1

[Jerry]

On Wed, Mar 13, 2013 at 3:03 PM, Joseph Fry <joe at thefrys.com> wrote:

>
> > I did make some headway on this issue by following the directions at:
> http://www.mythtv.org/wiki/__Overscan.   As a first go at it I just cut
> and pasted the metamode line that the author used (i.e. Option "metamodes"
> "DFP-0: 1280x720 { ViewPortIn=1280x720, ViewPortOut=1045x675+120+15 }" )
> and it worked like a charm.  Of course now I have underscan.  I don't
> really understand his/her arithmetic so I'm going to have to figure that
> out before I make any changes (baby steps). If anyone has an insight please
> let me know otherwise I'll just have to play with it until I get it right.
> I am optimistic though.
>
>
> First off, watch the top posting, always post inline or at the bottom of
> the quoted text.... allows people to read things in order instead of having
> to read from the bottom up.
>
> If I had to guess... the ViewPortOut value is simply the resolution and
> the offset.  So in the example you posted, the view port is actually
> 1045x675, and it is moved 120px to the right, and 15px down.  I assume the
> offset is from the top left corner (0,0).
>
> Imagine your screen is a typical X/Y graph... your screen (including it's
> overscan) is a rectangle grounded such that the top left corner is at 0,0.
>  The viewport is another rectangle that, unmodified is exactly the same as
> your screen.  What your doing is changing the size of the viewport in
> relation to the screen.... the problem is that by default the viewport
> remains grounded at 0,0, for example:
>
>
> ----------------------------
> |                   |      |
> |                   |      |
> |--------------------      |
> |                          |
> ----------------------------
>
> Use the offset to move the viewport to the center of your screen (or where
> ever it needs to be to display everything). Make sense?
>
> It's gonna take some trial and error to get both the size and offset
> right.  You may be able to make it easier by creating a wallpaper image
> that has a grid, say lines every 10px, on it to show you how big your
> viewport is, and how far you need to move the offset.  Of course this would
> only be useful BEFORE you set the viewport and offset.
>
>
I wrote that bit on the wiki.  It's just as Joseph described.  I think he
did a better job than I did.  :)

It took me at least a half hour to get everything working on my television,
shaving off and adding pixels to the relevant numbers.   I actually have a
wallpaper image linked on the wiki with a big white X on a black background
and white lines on the borders.  If that suits you, use that image as your
background image (stretched to fit your screen) to help you zero in.  In
this case, the end justifies the means!  It's totally worth it when you get
your screen tweaked properly.

My television is not very large and isn't an LCD/LED tv.  I used 1280x720
but perhaps you might have better success at 1920x1080.  With my
television, it doesn't matter much since the clarity is not very good.
(It's past time for a new television!)  A similar line would read something
like this:

Option "metamodes" "DFP-0: 1920x1080 { ViewPortIn=1920x1080,
ViewPortOut=RESXxRESY+offx+offy }

filling in RESX, RESY, offx and offy with your own numbers. (new resolution
x, new resolution y, offset x, offset y)

I was using the overscan adjustments built into mythtv until this last
upgrade that I made about a month ago.  For some reason, I couldn't get the
process to work any longer.  I stumbled upon this method after searching
the web for a solution.

Good luck!  I'll try to make that wiki entry a little clearer.
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