[mythtv-users] video curiosity, point me to the right mailing list

Chris Ribe chrisribe at gmail.com
Wed Sep 12 02:30:52 UTC 2007

On 9/11/07, Jay R. Ashworth <jra at baylink.com> wrote:
> On Mon, Sep 10, 2007 at 09:24:25PM -0400, Chris Ribe wrote:
> >    Unless there is a way to compensate for the image distortion before
> >    it gets to the monitor, that is. The problem with the monitor is
> >    that the red gun traces a line that is something like 7*sin(x/1920)
> >    lines above/below where it should be where x is the number of
> >    pixels from the left edge of the screen.
> >    In theory, if could just apply a filter to the red channel in X
> >    or the video driver, I could coax a reasonable picture out of my
> >    set without needing to fix the convergence. I'm intrigued by this
> >    possibility mostly because it is a much cooler solution than buying
> >    a remote. (If i just wanted an easy solution, I wouldn't be using
> >    mythtv).
> >    So, where should I start looking for ideas on how to accomplish
> >    this? I have one frontend with an nvidia 5200 graphics card, a
> >    macbook, and a frontend that needs a new video card (I had been
> >    hoping to use the integrated 945G video, but it is VGA out and my
> >    monitor only has a DVI input), so I am pretty flexible when it
> >    comes to video drivers.
> Your math says it's a one-channel vertical linearity problem.
> But, as great a guy as I think you are, Chris: you're nuts.  :-)
> Buy the remote.

I wish I could, but I'm wicked poor.  C'est la vie.

I've got another lead though:  I've found a JP1 configuration file for
emulating the missing remote, and I have an IR blaster.   Now I just need to
figure out how to  translate JP1 to lirc.

Unfortunately, google hasn't ever heard of anyone doing this, either....

For the record, the closest I got to accomplishing my color shifting goal
was the mplayer "-vf geq=" option.

"mplayer -vf geq=p(X\,Y-7*sin(4*X/W))  video.mpg"

correctly shifts the red channel, but unfortunately takes the other channels
with it, too.  The result is wavy video at about 1fps.  Oh well.

TV/IT Engineer
WCJB-TV Gainesville, FL
(352) 377 2020 x248
cribe at wcjb.com
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