Help! Certain color combo = badly rendered .avi

Jay Gladwell wrote on 6/4/2003, 6:32 PM

I'm experiencing a problem getting a clean render of red titles on a black background. I get the jaggies on the letters "S" and "G" and the diagonal on "N" ("TESTING"). I've tried NTSC colors (not that it's for broadcast), but to no avail. However, other colors work just fine, even white and bright yellow.

The specifics are:
Arial at 72 points
Centered
Bold "off"
Text Color is R=255; G=0; B=0; A=255
Background is R-16; G=16; B=16; A=255
Effects are all disabled

The text is clean and sharp on the timeline, prior to rendering. After rendering to NTSC DV (.avi) the "S" and "G" are very jagged, like bad anti-aliasing. Even the verticals "T", "E", "I", and "N" look like they have suffered bad anti-aliasing. I didn't have this problem under V3.0. This is the first time I've used this combo with 4.0.

Any ideas as to what I am doing wrong or overlooking? When the text color is changed, as I mentioned, and then rendered, there are no problems!

Any help and/or suggestions will be great appreciated! Thanks!

Jay

Comments

jetdv wrote on 6/4/2003, 10:21 PM

Your problem: It's TOO RED. Some colors are bad. Red is one of them.

farss wrote on 6/5/2003, 6:47 AM

There's a really good articel on this issue somewhere, just cannot find it at the moment.
But anyway in a nutshell 100% red is a no no, its not even broadcast legal, notice the little warning icons when you try to set a color to that, thats what they're for. Also when you working with generated media keep checking in the scopes, anything outside 100% is trouble, sometime it might even render OK as DV has more latitude than composte systems and the transmission systems.

With graphics try to use colors in adjacent quandrants on the vectorscope. Using opposing colors causes excursions that composite video just cannot cope with.

You've got to balance this up with just what your doing with your material. If its never going to be transmitted you can push things a bit more, if its only for viewing on a PC even more so.

If you want to see a simple example of this just look at color bars, you'll see on your PCs screen they look just great, on an analogue monitor look at the transitions, some are OK, others ring making the edges messy.

Jay Gladwell wrote on 6/5/2003, 7:11 AM

Farss said, "...red is a no no, its not even broadcast legal, notice the little warning icons when you try to set a color to that, thats what they're for."

As I said, this is not for broadcast. Yes, I'm familiar with the warning icon. It doesn't appear when setting the red at 255. It did appear when I set the yellow at R=255; G=222; B=0. Still, when rendered, it came out sharp and clear.

I've yet to have it explained as to why it appears fine before rendering and not afterward. That is my real question. And as you pointed out, it's DV, which has greater latitude. It should not degrade at all. It didn't using VV3.0!

Jay Gladwell wrote on 6/5/2003, 7:28 AM

Green and blue did the same thing, which they shouldn't. There were no warning icons, either. Something else is happening here that shouldn't be. The question is "what?".

Chienworks wrote on 6/5/2003, 7:34 AM

The problem could be DV itself with it's 4:1:1 sampling. Strong colors will show pronounced pixellation, especially on steep diagonal edges and curves. Try rendering a short section to uncompressed AVI as a control and see what happens there.

Jay Gladwell wrote on 6/5/2003, 7:55 AM

Thanks, Kelly! You da man!

That worked--no change whatsoever, clean, crisp, sharp edges.

I've read here, more than once, there is no difference between rendering as DV and uncompressed. Obviosuly, this isn't entirely true.

Thanks again.

SonyEPM wrote on 6/5/2003, 9:09 AM

"I've read here, more than once, there is no difference between rendering as DV and uncompressed."

Whoever wrote that is wrong or the statement was used in some specific context that doesn't apply in general. DV compression does result in a hit no matter what codec is used. However, if you use the external monitor function of Vegas, you'll be able to catch compression oddities like this before rendering (never mind delivering) the show.

bruceo2 wrote on 6/5/2003, 9:57 AM

can an uncompressed avi be printed to tape with SF capture?

Acts7 wrote on 6/5/2003, 10:24 AM

I would like to know the answer to Bruce02 's question also

Can an uncompressed avi be printed to tape with the capture utility
And WHEN would you want to use this as opposed to another option?

Thanks

-Acts7

SonyEPM wrote on 6/5/2003, 10:35 AM

You will not be able to print uncompressed to DV no matter what.

Chienworks wrote on 6/5/2003, 10:52 AM

If your computer is fast enough to handle the task and you have a video card with analog TV outputs, you could play an uncompressed AVI file in any Media player at full screen and send (print) the output to an analog VCR (such as VHS) and skip DV completely. You won't get a DV tape this way though.

Jay Gladwell wrote on 6/5/2003, 10:57 AM

So if I understand you correctly, even rendering uncompressed then transferring to tape (it being DV) will create the same problem?

Chienworks wrote on 6/5/2003, 11:05 AM

Well, if you want to get to DV tape, then somewhere along the way the signal has to be converted to DV, and that means 4:1:1 sampling. That's what DV is and there's no way around it.

Maybe sometime soon there will be a "DV-2" that supports 4:4:4 sampling and HD. Don't hold your breath, but do start saving your pennies, and quarters, and $100 bills ....