Help, beziers nearly drove me nuts

farss wrote on 3/26/2006, 3:25 AM
Anyone managed to use these for heavy duty work, like cutting out a moving object?
I've given up and found a way easier way to rebuild what the client screwed up in FCP so please don't anyone write me a full tutorial on this but here's what I'm seeing as a serious limitaton:

Working with interlaced video I need to get the mask pixel accurate, problem is the thingy I'm trying to mask is moving, fast, so which field am I working with here? If the mask doesn't track accross both fields then the edges get aweful.

As for why I'm having to do this, don't do a freeze frame without de-interlacing and then add a fast moving super over that, took me a while to even work out what was going wrong, looked fine in the preview window at Preview cause you only see one field, the resulting DVD looked rather bad on the TV though.

Bob.

Comments

TeetimeNC wrote on 3/26/2006, 4:05 AM
Bob, I haven't done this but I think you would need to deinterlace the footage before doing the masking. Here is an After Effects rotoscoping tut where they do just that:

http://72.14.203.104/search?q=cache:kpzD8HPYTB4J:www.creativecow.net/cgi-bin/page_wrapper.cgi%3Fforumid%3D%253CFORUMID%253E%26page%3D/articles/oneil_bill/as_matte/index.html+bezier+mask+interlaced+video&hl=en&gl=us&ct=clnk&cd=7&lr=lang_en
farss wrote on 3/26/2006, 4:43 AM
That thought did enter my head, in fact de-interlacing the footage could well have fixed the problem in the first place and then I would have avoided the need to use beziers.

Problem is intercutting de-interlaced with interlaced footage just doesn't work, not when it's go fast moving action and graphics. And for that reason I do need to keep the rest of it as interlaced.

Well at least I guess I've not missed something, rotoscoping etc interlaced footage seems to be beyond most application then.

One could I guess render out fields as frames, work on that at 50p and then convert back, I bet with the aid of Avisynth it could be done.

Bob.
GlennChan wrote on 3/26/2006, 10:55 AM
Not that this helps you, but Shake does allow you to work on fields.

EDIT: I haven't tried rotoscoping interlaced footage in Shake... I'm not sure if it works perfectly.
David Jimerson wrote on 3/26/2006, 11:05 AM
This will be an imperfect solution,but . . .

You could try working on a progressive timeline -- that way, you'll at least see the comb artifacts of the interlacing. You could try to create a mask which splits the difference?

Then, just switch the project properties back to interlaced. Vegas is the #1 do-it-on-the-fly NLE out there, so it's a great advantage.
farss wrote on 3/26/2006, 11:42 AM
The preview window in effectively progressive when it's at Best, you do see both fields, ah but I see your point, the pan / crop window isn't, your idea is one small step forward.
Splitting the difference is the problem though, when the object has moved 20% of the screen between fields that's a big difference when you're trying to say mask out a super.

Bob.