[mythtv-users] 1920x1080i source on 1920x540p output, video is narrow

[Daniel Walton]

I found a great powerstrip guide:

http://www.ramelectronics.net/html/powerstrip.html

Following it gave me the following modeline

"1920x540" 81.562 1920 2056 2248 2400 540 549 554 569 -hsync +vsync

It isn't perfect but it is close, I only have a little bit of vertical overscan.
I also set the DisplaySize to "160 90".  The combination of the two has fixed my
narrow image problem!!

Thanks to everyone for your help!!

Daniel

On Thu, 8 Apr 2004, Daniel Walton wrote:

>
> On Thu, 8 Apr 2004, Doug Larrick wrote:
>
> > On Wed, 7 Apr 2004, Daniel Walton wrote:
> > >  "848x480" 36.789 848 944 1024 1088 480 509 515 563 +hsync +vsync
> > >  "960x540" 40.806 960 1056 1136 1216 540 550 551 563 +hsync +vsync
> > >  "1920x540" 80.986 1920 2064 2256 2416 540 547 548 563 +hsync +vsync
> > [snip]
> >
> > John Patrick Poet wrote:
> > > Here is what I use (thanks to Doug Larrick):
> > >
> > > # 960x540 progressive, pseudo-1080i
> > > Modeline "540p" 39.956 960 1020 1100 1184 540 550 551 563 +hsync +vsync # 39.956 MHz 33.75 kHz 59.94 Hz
> > >
> > > # 1920X540 progressive, pseudo-1080i, 2x 540p's H timings
> > > Modeline "540pw" 79.912 1920 2040 2200 2368 540 550 551 563 +hsync +vsync # 79.912 MHz 33.75 kHz 59.94 Hz
> >
> > Indeed, Daniel, you'll notice that your 1920x540 modeline's H values
> > (the first 4 integers) are not 2x the better-working 960x540 H values.
> > Indeed, your modelines work out to:
> >
> > 848x480:  36.789 MHz dotclock, 33.81 kHz hrefresh, 60.06 Hz vrefresh
> > 960x540:  40.806 MHz dotclock, 33.55 kHz hrefresh, 59.60 Hz vrefresh
> > 1920x540: 80.986 MHz dotclock, 33.52 kHz hrefresh, 59.54 Hz vrefresh
> >
> > Those H refresh values are close enough to 33.75 kHz that your TV senses
> > "1080i" and switches to that mode.  But your V refresh values are off
> > from the broadcast standard of 59.94 Hz just enough that you'll get a
> > video stutter every once in a while.  But I don't see anything here that
> > would cause severe underscan.
> >
>
> I have overscan, its just that when myth or xine play the video the picture is
> really narrow.  Sounds like you may have figured out why in the next paragraph.
>
> > You definitely *need* a DisplaySize option for the 1920x540 mode -- it's
> > the only thing that tells Myth that your pixels aren't square (in fact,
> > they're twice as high as they are wide).  Without this option you'll
> > definitely see a half-size picture horizontally centered on the screen.
> >
>
> That is good to hear.  I'll give this a try and get back to you.
>
> Daniel
>
> > TVs, even HDTVs, are set up to overscan so they cut off any noise at the
> > edges of the picture, or geometry problems with the CRT -- as opposed to
> > computer monitors, which are set up to underscan so you can see the
> > whole picture.  In order to use an HDTV as a computer monitor, you'll
> > have to use a "subset" mode like your 848x480 one, though I'd suggest
> > getting the "pure" modes working properly first.  Actually I'd suggest
> > just cribbing mine :-)
> >
> > -Doug
> >
>
>