Roto: is blurring a mask is a common thing?

[Dias]

Hi guys

I'm practising in roto by myself few weeks already and I often have the same issue: random color pixels around object/person I'm roto-ing (due to the compression of the source). I've tried several "do_something_and_see_what_happens" methods like color suppression using second bigger mask, or trying to include that pixels in my roto as well, but results weren't good enough. Now I'm trying the easiest solution ever, I just blur my mask (relatively small amount, like 7 px), which seems to work pretty well.
I was just curious how do you deal with this kind of issues in production environment? Do you often blur your roto masks? I'd like to know if I'm on a right track. :)


Bye,
Dias

[NickJushchyshyn]

Blur really doesn't compensate for compression artifacts. A soft blur really doesn't simulate the results of compression.
In most production environments, it's rare to be working with heavily compressed plates.

Since you're already in roto .... you could just paint out the worst/most-noticeable of the compression artifacts. Another alternative would be to have extra masks to roto around the compression as needed ... keep these out of frame when compression is not a problem, then bring them in for the individual frames that have problems to isolate the specific artifact as needed.

[bio]

What resolution are you working on?

[Dias]

Hi guys, thanks for replies.

Resolution of the footage I'm working on is 914x494, not really an HD awesomness but decent enough for learning purpose, especially when you have no access to HD stuff (hmm, I nearly forgot about my FXPHD material, I have to check it out). :)

Anyway you're right, I already see troubles that little blur can cause me (tiny constant glow around my object became too visible on certain backgrounds), I'll try you advises. :cool:

Btw, I was curious about another issue. Let's say there is a girl on your footage and you have to roto her green T-short. No problem to roto that T-short, but how to you deal with that little green irradiance on her neck caused by T-Short? Do you include that in roto as well (I doubt it), or you roto/suppress her neck separately?

Thanks again

[NickJushchyshyn]

Yup. Typically, the neck in a situation like this would have it's own roto mask (or layer of roto masks) so it can be isolated separately. The gradient of the color spill could be handled procedurally in comp, but roto would be used to isolate the neck itself for the de-spill work.