Complex chroma key matting problem

[poisondeathray]

However, for your matte layer it doesn't matter. It would be easier to apply filters to 6sec clip and use a lossless intermediate (e.g. lagarith, huffyuv, even uncompressed) and re-import that filtered clip.

The problem is, the "clip" I'm using is actually cropped from much longer footage. So I have the problem of either re-encoding the entire video footage, or cropping the piece of footage and applying the filter. I think that would mess up the timings in my project, especially in the latter case,

You mean cut (in time) not cropped as in borders cropped right?

Eitherway it doesn't matter.

You're using vegas! It's an NLE! Timing doesn't matter you can slide clips wherever you want

For the crop issue, you can a garbage matte

A garbage matte is just a rough outline mask to isolate the selected area. It literally takes seconds to draw a box around the selected area. Keyframing a garbage mask is easy to do as well (so it "moves" as the Enterprise moves), it's just very rough - you don' t need any accuracy

It doesn't need the pixel perfect precision as rotoscoping, it's job is just to make a rough outline to reduce the work necessary for your other filters

In your case, the other filters will take care of everything else (whatever you used to get the green shot in the 1st post - but if you did the same thing using the prefiltered clip, the one with the obliterated stars, can you see how that would produce what you want ? Because the stars are gone, there will be no more holes)

When you're done, your matte layer should look like the one I posted earlier (the green or white examples surrounded by all black)

A matted layer with the star trek piece can then be inserted into any project you want, at any timeframe you want. You're just breaking it down into steps.

Your first step is garbage matte the 6 sec enterprise clip - export without alpha channel (ie. ordinary RGB clip) , then apply denoisers in other programs (maybe vdub or avisynth ) , then reimport the "obliteratted star" clip back into vegas and apply whatever you did to get the green image in the 1st post to generate your matte layer

[Morality124]

Sorry, I made a mistake in my post. I meant to say that I had "trimmed" the original clip in Vegas, not "cropped". I can see how my post didn't make any sense. Sorry budwzr. You can come back.

OK, I do understand the method which you are explaining. Essentially, I am modifying the original footage with the deoniser and using that to create the matte layer, then I am replacing the other matte layer with this new "de-star-ed" one. I do understand this.

By "garbage matte", are you refering to the result of deonising the footage and using that combined with the filter I used as the matte? Or is it a seperate thing altogether? Where does "drawing an outline" come in? Would I draw an outline in a different circumstance, but drawing is no necessary here?

The problem I am having isn't really with the concept. I do understand what much be done. The problem is getting there. Right now, I spent time trimming the original episode footage down to the ship scene I needed in Vegas, without changing the original clip. The original clip is around 300 megabytes. So what would be the most efficient course of action?

- I could trim the clip again in say, VirtualDub, save in a lossless format like you suggested, then apply the filter and save the clip again. The problem here is that I have already applied certain effects to the trimmed footage in my Vegas project, effect which have been specifically timed. So if I imported these new trimmed video clips, then I would have to redo those effects again.

- I could apply the filer to the source video clip and encode to a new copy. Problem is, this would take a long time, and there is no gurantee that I could tell Vegas to use this new version of the video clip for the Matte track (or that the timing wouldn't be affected by the reencoding). Maybe I am full of s*** here?

- I could save the trimmed footage using Vegas. Question is, would the timing be off, and would I be able to save it without affecting the quality? (I know you can in VirtualDub as you have already explained but what about Vegas?)

That is the problem here. I believe I do understand the overall process.

I hope I'm less vague this time.

[poisondeathray]

now i'm confused

ok forget about the garbage matte for now

you can have multiple copies or instances of clips with different filters - when you save .veg file, it references only the original video

you can have multiple layers within a project , or even projects within projects (nested .veg)

there are a dozen ways you can organize or approach this




eitherway - you need to make a matte of that trimmed 6 second clip of enterprise zooming by - now you can do this in a separate project if you want if it make it easier for you - you can even save it with alpha channel (RGBA) so it's prematted - i.e. it's only the enterprise. That RGBA clip can then be imported and composited into any project, even other NLE's. Maybe this would be easier for you? This would probably be the easiest approach as a separate "mini project" if you have to insert it into a larger project

The problem here is that I have already applied certain effects to the trimmed footage in my Vegas project, effect which have been specifically timed. So if I imported these new trimmed video clips, then I would have to redo those effects again.

I'm not sure what you're getting at here , because you're only making a matte (so the enterprise clip can "show through the hole". The enterprise clip that "shows through" I'm assuming will already have whatever effects you have applied - nothing changes) .

Essentially, I am modifying the original footage with the deoniser and using that to create the matte layer, then I am replacing the other matte layer with this new "de-star-ed" one. I do understand this.

It's just a copy of the original. You're just doing this for the matte, so the "original" plus whatever effects can "poke through"

- I could save the trimmed footage using Vegas. Question is, would the timing be off, and would I be able to save it without affecting the quality? (I know you can in VirtualDub as you have already explained but what about Vegas?)

You can save lossless eg. uncompressed, huffyuv, lagarith. You can even save RGB+A huffyuv or UT Video Codec (ie. save the alpha)




Maybe I'm not understanding what you're trying to do? What exactly is the background clip? Don't you just want to isolate 6sec enterprise flying and composite that footage onto a background layer or movie? Describe EXACTLY what your end goal is

[budwzr]

If you can just make a B/W mask from a snap, size it a few hairs bigger (the ship outline) than the original, then overlay it, and animate it, that's it, you're done.

Make the mask bigger (the black part, not the ship) than the project resolution so you can slide it around without the edges (stars) showing.

Imagine a model ship is on a table 2X4 feet and someone is pulling it across with fishing line, and you are holding a 4X8 Feet sheet of paper with the ship cutout in the middle of it. And imagine how you would move the paper to keep the ship within the cutout while it's moving, and do the same with the Pan/Crop/Zoom tool.

The way they animate the "real" Enterprise is with the cameras moving, not the ship. They dolly out and do something like a "Hitchcock Zoom" for the warp speed.