On 3/30/07, Eben King <eben01@verizon.net> wrote:
>
> On Fri, 30 Mar 2007, Levi Bard wrote:
>
> >> IIRC TVs use pixels a bit taller than square. 320x240 fills a 4:3
> screen
> >> on a computer, but it looks like 352x240 is required on a TV [1]. So
> TV
> >> pixels are 320/352 = 10/11 the width of a square pixel, or 11/10 the
> >> height of a square pixel, take your pick. So your 1280x800 screen
> should
> >> look 11/10 - 1 = 10% too narrow, or 1 - 10/11 ~= 9% too tall on a TV.
> Is
> >> that about right?
> >>
> >> [1] http://www.videohelp.com/vcd#tech2
> >
> > Video encoding and playback are totally different than standard
> > display. You encode an ntsc vcd at 352x240, but the 4:3 aspect ratio
> > is embedded in the mpeg stream so that it actually plays back at
> > 352x264. (You'll notice this if you play a vcd using
> > mplayer/xine/vlc.) DVDs are the same way. You encode at 720x480
> > (NTSC), and the aspect ratio is embedded in the mpeg stream, so that
> > it plays back at 720x540(4:3), 854x480(16:9), or what have you.
>
> It probably depends how smart the projector is. If it's excessively
> literal, it may display the image pixel-for-pixel, aspect ratio be damned.
> Since he has to crop the image to make it fit 16:9_TV, and it started
> fitting 16:9_computer, I'd say _something_ is being excessively literal.
>
> --
> -eben QebWenE01R@vTerYizUonI.nOetP royalty.mine.nu:81
When I have the PC going on the projector, the computer says that it is
using 1280x720, and the projector says that it is using a 1280x720 source.
The aspect ratio looks correct on all pictures, shapes, and video, but there
is a black bar on each the top and bottom of the screen. The horizontal
sync and vertical refresh are not actually in the user's manual (imagine
that!), but Optoma has published on their website Horizontal Scan Rate of
15-75 KHz and Vertical Refresh Rate of 43-85 Hz. Is "Horizontal Scan" going
to be the same as "HorizSync"? If xorg will indeed not support 1280x768,
what would a suitable solution be? Is an XF86Config file going to be able
to support where xorg will not? Are there other alternatives that might?
It looks as though there are versions of MythTV that will run on any distro,
so I suppose it doesn't really matter which one I use in the end. I know
that a lot of widescreen monitors are in this same screen resolution, and
I've seen anecdotal evidence on the internet that Linux can be coaxed to do
it, just nothing to inspire me as to what I'm doing wrong. Another thing
that I find interesting is that when the computer boots, the projector says
that it finds a 1280x720 source prior to X starting, even. That makes me
wonder if it's a hardware limitation of some kind on the computer end, or
possibly a bios problem. Are certain video cards limited on what display
modes they will support?
--Michael
Only two things are infinite, the universe and human stupidity,
> and I'm not sure about the former." -- Albert Einstein
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