How to subtract

[John Rofrano]

[Alen Koebel] “What I want to do is subtract a clip of the same length containing only dark frames, which contain exactly the same fixed pattern (I may have to increase or descrease the “gain” ). How can I do this?”

If you are using Vegas Pro, place the clip you want to subtract on a track above the video and change the Track Composite mode to Subtract. If you are using Movie Studio you can’t do this.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Alen Koebel]

Thanks. I knew this had to be basic, which is why I posted it here. Somehow I missed that in the Vegas 10 manual, but there it is on page 331 (I’m using the trial version). Can you see the egg on my face?

Regarding Movie Studio, which is what I actually have, I can only hope Sony adds that and the other compositing modes to v12. Heck, here I am editing my first video (remember when?) and I find I already need subtract and could use event velocity control, two of many features not in Movie Studio.

Second question: Does anyone know of a workflow whereby I could do subtraction for my purposes outside of Movie Studio (or other NLE), either by creating an intermediate file or frame serving one to Movie Studio? Is it possible to use avisynth to do the latter? It seems crazy to me that I can’t do a relatively simple mathematical operation (as these things go) like subtracting two video files without springing for Pro. Can any other low cost NLEs do it?

[John Rofrano]

[Alen Koebel] ” Does anyone know of a workflow whereby I could do subtraction for my purposes outside of Movie Studio (or other NLE), either by creating an intermediate file or frame serving one to Movie Studio? Is it possible to use avisynth to do the latter? It seems crazy to me that I can’t do a relatively simple mathematical operation (as these things go) like subtracting two video files without springing for Pro. Can any other low cost NLEs do it?”

I don’t know of any low cost NLE’s that can do this and I don’t believe that you can solve it with frame serving because it requires two tracks in two distinct video streams to do the subtraction. You’d need something like After Effects that cost more than Vegas pro so you’d be better off upgrading to Vegas Pro.

If you need velocity envelopes and advanced compositing, it sounds like you really do need Vegas Pro for your editing needs.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Alen Koebel]

Update (FWIW): I tried doing what I described in the trial version of Vegas Pro 10. It didn’t work. The problem of how to get rid of this particlular camcorder’s FPN is evidently more complicated than I assumed. What did work however, is, the Neat Video noise reduction plug-in (again, tried the demo version). But frankly, used at the highest level I could tolerate that _didn’t_ destroy too much detail, it was not much if any better than Mike Crash’s Smart Smoother plug-in, which is a whole lot faster (not to mention free). Interestingly, using Mike Crash’s temporal noise reduction plug-in (the other one he offers) actually made the pattern noise much easier to see by getting rid of the random noise. Not surprising in retrospect.

Re needing Pro, ironically if I were using a better (more $$) camcorder and had more experience shooting video, I wouldn’t need some of the advanced festures of Pro that I said I could use. I guess the lesson is you end up paying somewhere along the line. 😉

[Andrew Pollock]

Of course he can do this using a frameserver (Overlay in AviSynth). The challenge is getting the AviSynth script to open in Vegas without having to render it first.