[mythtv-users] Excellent quality TVOUT from almost any video card

papenfuss at juneau.me.vt.edu papenfuss at juneau.me.vt.edu
Thu Jan 29 14:56:07 EST 2004

On Thu, 29 Jan 2004, Tim Gray wrote:

> Interlaced modes? I dont understand, X windows doesn't
> have the ability to generate interlaced video,
> otherwise a scan converter would not be needed.

	That's a false statement.  XFree86 is capable of supporting interlaced 
modes with the right combination of hardware and driver support.  That's 
exactly what I'm doing with my homebrew NTSC converter and Rage 128 vid card.  
A scan convert would still be needed, however, unless you program the modeline 
to produce exactly the right horiz/vert freq for NTSC (15.7 kHz/59.97 Hz 
interlaced)... which is what I did.

> I simply deinterlace everything I record to solve any
> interlacing problems I might have. I also transcode
> everything I want to keep to a divx which is
> deinterlaced anyways, or create a SVCD.

	Maybe so, but if it's recorded from TV, it started life as interlaced 
(unless telecined, which is another can of worms).  It's also ending life as an 
interlaced picture (on standard NTSC non progressive-scan TV's anyway)

> It also is working at full resolution. I can read
> command prompt 80 col text on the 5" editing monitor I
> have here for testing.
	Find out for sure... run a "high res" on your X-server (800x600) at 
least.  Scale this image fullscreen.

See how many lines you can resolve.  With the board I built on the Svid 
connection to a projection TV, I can see about 480 horizonal lines (as expected 
with 720x480 resolution).  The vertical lines (classical "lines of resolution" 
with a 4:3 scaling factor) peters out at about 450 lines as well.


* The prime directive of Linux:  					*
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