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Spatial masks based on edge detection?

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Michael McCune
Spatial masks based on edge detection?
on Nov 25, 2016 at 11:43:20 am
Last Edited By Michael McCune on Nov 27, 2016 at 1:21:25 am

It seems that for roto type work we have manual polyline as the main tool. Tracking extends that over neighbor frames. And qualifiers within power windows can key on selected pixel values. All seem to work ... With lots of case-specific reservations and caveats.

But often I recollect and yearn for a paint brush type of *spatial* selection tool, as we have all used in Photoshop. It's spatial edge detection works quickly and well. And those marching ants with a paint brush can further refine the edges.

So when Resolve qualifier special case caveats drive me nuts I find myself wondering if I am missing some magic wand edge detection capability in Resolve???

That is, a tool that finds *shape* edges and not just a collection of
pixels with similar values, which seem to invite chattering and sometimes limited success using the mate finesse tweaks.

Thanks, Mike


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Hector berrebi
Re: Spatial masks based on edge detection?
on Nov 29, 2016 at 9:08:34 am

Hey Mike

I sort of tend to agree that it would be a nice tool to have. ☺

I tend to think that in color work for video, we need softer types of masks, however, since hard edge masks can be softened, a tool that would further help generate them can't be a bad thing.

here are 2 optional solutions for you till Black Magic adds one in.

1. After Effect Roto Brush - this must be one of the simplest auto roto tools I ran into and if you're comfortable using AE (which is a fairly straightforward software) then exporting high res cuts from Resolve that need that special care to AE shouldn't be a hard task. In AE, once you master the Roto Brush tool, create and export a B&W matte, which you can then import as matte into resolve and feed into the node you need to adjust. not amazing... but quite simple workflow (especially since cuts tend to be short and cuts that problematic are rather rare)

2. Fusion Roto Assist - Which is as of recently a Black Magic tool has very strong roto tool set with edge detection technology. I believe you'll need payed versions to round trip (not sure if you need both, but simple to check) with Resolve timelines. you could probably use the matte export workflow for free... but I think its bit easier with AE.

I wonder.. since BM owns the tech, if someone there considers migrating this (or other) tool from Fusion to Resolve.

Or.. you could write a good OFX plugin ☺ I'm sure it can be quite popular if fairly priced. I'd buy it.


hector.


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Marc Wielage
Re: Spatial masks based on edge detection?
on Dec 4, 2016 at 2:33:27 am

[Michael McCune] "But often I recollect and yearn for a paint brush type of *spatial* selection tool, as we have all used in Photoshop. It's spatial edge detection works quickly and well. And those marching ants with a paint brush can further refine the edges. "
I would not be surprised to see greater collusion (if that's the right word) between Resolve and Fusion for those who have enough RAM to run both programs at once. As far as I know, similar color-correction software like Baselight, Lustre, Nucoda, and Pablo all have limitations on tracking; Lustre has the advantage of being able to hand off to Flame, and I would bet there's some edge-detecting features there. Mistika does have some very interesting VFX capabilities, but I've been told it has more issues with color correction.

Often, my sad lesson learned over the years is that what you have to do in order to solve problems is to adapt to the software, not to curse the software for not being what you want it to be. There's always a workaround, and I'd also say no one piece of software can be a Swiss army knife that does everything for everybody. You might look into Boris Continuum and see if some of those features would help as an OFX plug-in.


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Michael McCune
Re: Spatial masks based on edge detection?
on Dec 8, 2016 at 2:02:57 pm

Totally agree regarding knowing the tools one has as thoroughly as possible though this sometimes requires the patience of a saint.

AND a little realism regarding the actual effort to learn a new application sufficiently to be useful gives me pause as well.

Nevertheless for these knotty issues of tracking and making, perhaps Fusion is "most likely to succeed." It is, after all, a compositing program.

And I find myself with-- yes, it's true-- two or three dozen nodes for a single shot. Say, three people, each with perhaps three masked areas for face, eyes and clothes. Plus some background objects to be lightened or dimmed. Using almost everything: layer, parallel and key mixers, pre-clip vignettes, hundreds of keyframes.

Wish tracking didn't crash so much; makes me nervous. Seems to relate to animation that uses both standard timeline keyframes AND tracking timeline keyframes.

Onward and upward!

Thanks, Mike


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Marc Wielage
Re: Spatial masks based on edge detection?
on Dec 8, 2016 at 2:11:30 pm

[Michael McCune] "And I find myself with-- yes, it's true-- two or three dozen nodes for a single shot. Say, three people, each with perhaps three masked areas for face, eyes and clothes. Plus some background objects to be lightened or dimmed. Using almost everything: layer, parallel and key mixers, pre-clip vignettes, hundreds of keyframes. "
I find that can work in very complex situations, provided you have lots of time and budget to cover it. If you're trying to get a 12-shot :30 second commercial done in 3-4 hours, it'd be tough. Impossible with a feature film that has to be done in 2 weeks (which is my usual gig), or a network TV series that has 20 hours for 45 minutes of material. I can and have done 20+ nodes for very unusual situations, but I think sometimes it's good to take a step back and question whether there might be a simpler way of achieving the same results.

On the other hand, films like The Revenant were done with upwards of a dozen tracking windows relighting every single shot with thousands of keyframes, many of which were manually roto'd by hand, using a half-dozen people, each working 10-12 hours a day, 6-7 days a week, for months on end. So as long as the time and budget is there, go for it.


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Michael McCune
Re: Spatial masks based on edge detection?
on Jan 5, 2017 at 5:18:12 pm

You mention The Revenant and its relatively heavy use of masking and color and the consequent huge number of hours and budget required.

I would love to know more detail about that film's "making-of" processes. It is one of only a few films which I have watched several times because of its beauty and visual poetry.

Is there a Revenant "behind-the-scenes" or "making-of" video online, especially regarding the colorists' work ???

I have seen all of the "behind-the-scenes" videos at Cinematography Database (



), Every Frame a Painting (



), Variety (http://variety.com/v/video/), and other videos.

Thanks, as always Mike


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