[mythtv-users] Hardware for Best TV-Out?
papenfuss at juneau.me.vt.edu
Thu Oct 28 21:28:18 UTC 2004
> | I thought you said that the Harmonic Research does exactly
> Sorry, I was unclear. I meant a complete solution to provide NTSC out for
> Myth. Without seeing for myself, I don't yet accept your premise that
> running the RGB output of an nVidia card through (even a good) NTSC encoder
> will give me what I want. :) I'd have to think about whether it would be
> worth spending the money just to try.
"Complete solution." Boy, that's marketspeak if I ever heard it!
:) Seriously, though, the biggest problem I've had with mine is
convincing a video card modern enough to do Xv to go low enough and
produced bugless interlaced video. I can assure you that the quality of
what I've cooked up is much better than any TVOUT card I've ever seen. I
was fairly careful on the PCB layout and termination of the video lines,
etc. Also, the AD724 is a SMC chip, so it keeps the inductance low, too.
I'm sure that a crappy layout will produce crappy results (part of why I
haven't built a RGB->Component transcoder yet... too lazy to lay out a
> This is interesting. I have a CV233. The RGB version is the CV223. The
> CV121/CV131 series used to be the ones that did not provide a locked sub-
> carrier and cost less than half as much. Looking at the description of
> the CV121A/CV131A they now list locked sub-carrier as a feature! I wonder
> if they really changed the design or this is more market speak. If they
> really changed the design and kept the cost low, I can't see why anyone
> would bother with the CV2* series anymore (surely not just for the BNC
Here's something you might try to see if it's worth investing more
into the experiment. I did this the other day to simulate B&W NTSC from
the VGA card. If you've got a VGA->BNC or equivalent breakout, try using
a vid card with sync-on-green into the Y-channel of your component->NTSC
box. You'll only get B&W (of green), but it's good enough to get
luminance resolution, look for ringing, and see if the RF-modulator like
the line-locked signal it produces. Actually, aside from the colors being
good-n-groovy, go ahead and put R&B on there as well... then you *will*
get (horribly wrong) color to test.
That's a pretty cheap test, even if you don't have the $20
RGB->BNC breakout cable. I've had *really* good luck with Matrox cards
and funky vid options (sync-on-green, csync, interlace, low clocks, etc).
The Millenium doesn't do Xv, but for a static test burn the CPU for
psychodelic-colored video... :)
> |You could always buy/build an RGB-Component transcoder (an
> |analog generation loss, though) to run through the one you've got.
> Yes, I've considered that.
> Dan Lanciani
> ddl at danlan.*com
Might have renewed vigor if the RGB one works. I was going to
build rev2 of my circuit here when I get some time, so I'll look into
replacing the crystal with a PLL. If I get something that's user-friendly
for others, I'll post a page describing the construction.
More information about the mythtv-users