Variable brightness filters -- any ideas

Paul_Holmes wrote on 10/7/2002, 8:58 PM

There are times I would like to overlay my video with a filter that varies the brightness of the picture from left to right, right to left, top to bottom, etc. For some reason it's slipping me what the name of these physical filters, often used by photographers in filming backlit scenes. I bet there's a way to do this in Vegas. Anybody have any ideas?

Comments

SonyDennis wrote on 10/7/2002, 9:09 PM

I think they're called gradient filters.

Sure you can do this in Vegas; use a Gradient generator (color or gray scale) on a track above your video, and pick an overlay mode that does what you want.

///d@

Paul_Holmes wrote on 10/8/2002, 8:09 AM

Thanks for the tip. I kind of overlooked those filters not thinking I had any use for them at the moment, but I will look more closely at them.

sqblz wrote on 10/9/2002, 6:31 AM

SonicDennis, overlaying and compositing are just two things that have not yet entered my head (just my fault ...).
Could you please elaborate a little, explaining how to use them here ?
Thanks

Paul_Holmes wrote on 10/9/2002, 1:12 PM

I've experimented with this a little now. Go to the Text/Backgrounds tab and click on the Color Gradient Filters. I've been playing with Linear Black to Transparent and it's configurable to do what I want, make one section, or corner of the video darker while gradually going from dark to transparent in the rest of the frame. This should work great in static shots, where part of the video is glaringly brighter than the subject.

SonyDennis wrote on 10/10/2002, 2:14 PM

sqblz:

There are some really nice sections of the manual and online help that explain compositing and overlay modes, have you checked those already?

///d@

Paul_Holmes wrote on 10/10/2002, 7:12 PM

No, but I was trying to get it done the quick and lazy way. Anyways, I will be sure to peruse the manual a little more. It IS quite extensive.

sqblz wrote on 10/11/2002, 4:22 AM

Paul Holmes, SonicDennis was pulling my ears, not yours ... ... :-)

Yes, SD, I have read the manual. I used it so much that it is worn out. Time for reprinting it, I was just waiting for SoFo to include the 3.0c updates (hint, hint <G>)

Anyway, yes, I did read it. But the theme (compositing) is quite confusing to me, because I am just a home user. I haven't been able to grab the concept that lies behind compositing (using one image to filter another ?) so I never think about compositing when I am planning my projects.

With time, I came to the conclusion that you guys/gals have done with VV everything that comes to your mind as a project. But I don't think that I am using more than 50-60% of VV's potential... compositing is just one of my drawbacks.

Before you ask: yes, I have perused through the tutorials also.

SonyDennis wrote on 10/11/2002, 1:14 PM

sqblz:

OK, I'm glad to hear you read the manual & help. I'm sorry if it didn't explain these things well enough; however, I'm not sure my description will be any better.

Compositing is the act of layering images or video. In order to do this, the video on top needs to have transparency. This can be for the whole image (using the track opacity fader, the track opacity envelope, or individual event opacity envelopes), or for sections of images (image/video that has a transparency channel, called alpha, or image/video that has transparency generated using Chroma Keyer or Masking). Generated text often has a transparent background so that it can composite over video.

Multiple video tracks stack bottom to top, with top tracks compositing over the bottom tracks. Usually, they just compositing over the top using the transparency, but other overlay modes are available, including subtraction, and multiplication.

Masking is adding transparency to an image/video. If you use a white circle on a black background as a mask, it becomes a cookie-cutter of the image/video, creating transparency around the edges. Vegas uses track grouping to do masking (it's the little button on the left of a video track, when you have 2 or more).

///d@

FadeToBlack wrote on 10/11/2002, 2:58 PM

sqblz wrote on 10/15/2002, 9:44 AM

SonicDennis and GG;
You are both right and give me the will to go.

Right now I am re-reading the VV3 manual and doing some experiments with the technique. Like we say in my country "if you see an hungry man, don't give him food but teach him how to fish".

Of course, no-one will never need to use all the gizmos and tricks buried inside VV. It would make for an awful video !!!
My point is different: if I know that a certain facility is available, there will come a time where *that* facility will be the right one to use. But if I am not aware that it exists ...

I would like to see something like the "dummy's guide to compositing". Now that we are here, I would like to see the "dummy's guide to keyframing" as well ... Aaaahhh, and a true Catalog of Plug-Ins ...

I have closely followed the SoFo Tutorials, and also some amazing projects laid down to public domain by amazingly good fellows, but still I am missing the step by step approach (put this here. see ? now, move it to the right. see what happens ? ... ...)

Some of you would say that I am playing lazy. Unashamefully Yes !!!

Well, I guess I'll go and dedicate my next weekend to GG's suggestion ...