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-   -   Pulsing reds on DV print (https://www.dvinfo.net/forum/non-linear-editing-pc/4605-pulsing-reds-dv-print.html)

Dylan Couper October 26th, 2002 09:55 PM

Pulsing reds on DV print
I printed the final copy of my video to tape, and to my horror, some of the reds "pulse". As in people wearing red shirts that pulse light/dark, in/out, a few times a second. Know what I'm talking about? This isn't present on the original tape, so I'm guessing it's a software issue. I can cut all the scenes with the pulsing reds out so it's not important. It doesn't do it all the time, only in a 5 minute segment. There is no difference between that 5 minutes and the 5 before or after it.

SO, anyone know why?


Robert Knecht Schmidt October 27th, 2002 01:11 AM

Without knowing a lot more about your setup, one preliminary guess I could make is that somehow during editing you managed to coax the reds outside of the NTSC acceptable range. If you have a vectorscope in your editing software, check out what the red sequences look like. You might be able to rein them in through some chroma filtering.

Since DV is 4:1:1 sampling (the compression throws out more red and blue information in comparison to green) it can sometimes be finicky about reds. In my experience this usually means blotchy or icky looking reds. But pulsating reds? That is strange.

If it only happens for one small portion, it could be a bad tape. See if it still happens when you print out to a different tape.

Dylan Couper October 28th, 2002 05:23 PM

Sorry for not posting my setup, my bad. Editing on a P4 2ghz using Vegas Video 3.0. I outputed to tape twice in case it was a fluke. It was not, unfortunately.
I know what you mean, I've seen lots of ugly reds, blurry and discoloured and suck, but never pulsing.

Any more suggestions based on that info, or has anyone else had this happen to them?

Rob Lohman October 30th, 2002 08:54 AM

So you are saying it doesn't pulse when viewing on the computer?
Only when outputted to tape? Are we talking output to Analog
VHS tape or to miniDV? What recorder did you use if analog? SVHS
or composite signal?

Three things that come to mind:

1. analog interference whilst recording
2. IRE level changes from 16-235 to 0-255 or vice versa
3. plugins you used (like safe color and such)

Any bells starting to ring here?

Dylan Couper October 30th, 2002 02:54 PM

Rob, it does not pulse when viewed on the computer. Outputed to miniDV on the XL1 through firewire.
Didn't use any pulg-ins, didn't change anything.

I printed it to tape again, to see if it was a fluke, and it's still the same. Copied it to VHS and its still there. I cut the worst, most noticable parts out anyway, but I'd still like to know why it does it. Maybe I'll try capturing and printing a small section from scratch and see if it still does it.

Rob Lohman October 31st, 2002 06:11 AM

At this point I've got no clue.... sorry... Your best thing indeed might
be to redo it and see if it happens again. Elimination of causes
might lead to the answer.

Good luck!

Robert Knecht Schmidt October 31st, 2002 06:52 AM

What do the red parts look like on the vectorscope?

Jeff Donald October 31st, 2002 10:32 AM

I'm no PC guy so bare with me. When you export from Vegas Video, are there any preferences or settings that can be changed.? Is it possible your exporting in the wrong color space or wrong codec? I've seen similar things when video is rendered with the wrong codec.


Dylan Couper October 31st, 2002 12:37 PM

I have never changed the codec, so I assumed it's using the Vegas Codec. Vegas guys, how do I change the codec, or check to make sure it's using the right one?

Robert, have not checked vectorscope yet.
I'll do some more experimenting and make another print of it this weekend.

screenblaster October 31st, 2002 04:32 PM

Have you tried using the Broadcast Colors effect on the project with the clamp preset. This should give you legal colors for NTSC output. Use it on the preview window.

Here is the step by step.
-press the Video Output fx button on the preview window (the one that looks like a grey box with 2 little dots next to it)
-In the Plug-In Chooser select "Sonic Foundry Broadcast Colors" and add it to the chain.
-In the plugs' UI select the preset "Clamp"

-Now retry the print and see if this fixes up things.

To check that you are using the SF DV codec make sure of the following:

1. The pref "Use Microsoft DV codec" is UN_CHECKED
2. The pref "Ignore third party DV codecs" is CHECKED

Doing the 2 things above will garantee that DV NTSC renders use the SF DV codec.

Hope this helps...

Adam Lawrence October 31st, 2002 05:22 PM

hmm....ive had a similar problem in the past but with some vector shapes and
animation...I de-interlaced the footage before i outputted to video..this
is a standard filter than comes with most professional NLE software usually refered to "anitflicker" it helps in reducing general "video buzz" which sometimes makes your LOUD colors flicker....

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