Easy way to remove video backgrounds?

Krisqo · Post by **Krisqo** » Fri May 12, 2006 5:00 pm

I have heard all this talk about using Rotoscoping and masking to isolate items from frames in video. But how do you take a video clip and remove the background from it while perserving the motion. For example, I want to take a clip from "Kaleido Star" in which Sora is walking along the ocean and remove the ocean and replace it with various other clips. As it stands, the only way I can get this effect is to import every frame into Photoshop Elements (420 frames). I've read other posts that talked about making cutouts, but it is so tedious and time consuming. Is there an easier and less time consuming way to do this?

P.S. I've tried Rotoscoping in AE6.5 using the ereaser, but Sora disappeared behing what I had "ereased." I hate sounding like a nOOb, but I've never tried this type of editing before. Any help would be HIGHLY Appreciated.

CHAMELEON_D_H · Post by **CHAMELEON_D_H** » Fri May 12, 2006 6:13 pm

Using keys. For that particular scen I'd use chroma key, and get the ocean out of the way. BUT, if the walking is repeatative, yu should go for the masking technique, as it is much more accurate.

Krisqo · Post by **Krisqo** » Fri May 12, 2006 8:54 pm

CHAMELEON_D_H wrote:Using keys. For that particular scen I'd use chroma key, and get the ocean out of the way. BUT, if the walking is repeatative, yu should go for the masking technique, as it is much more accurate.

The walking is repative. In the fifteen seconds, she travels about half way across the screen. I've included the clip here as a refrence.

http://s2.photobucket.com/albums/y37/Kr ... edwakl.flv

This is probibly such a nOObie question, but isn't masking the same thing as putting the frame into Photoshop and cutting out what you do not want? Or is it done by creating a motion path? I swear to god, i'm new at this stuff and it's making no sense. I even have my Adobe After Effects manual sitting beside me trying to figure out what keys are.

Krisqo · Post by **Krisqo** » Fri May 12, 2006 9:08 pm

I wonder why I cannot edit posts? I hate double posting.

Anyway, I played around with all the keying options in Premiere (AE only had the Luma key, CC Simple Wire Removal, Color Key, and Color Range) and it did nothing but blank out the image.

Castor Troy · Post by **Castor Troy** » Fri May 12, 2006 9:23 pm

Are you properly adjusting the mask/eraser with the keyframes?

Krisqo · Post by **Krisqo** » Sat May 13, 2006 8:22 pm

Castor Troy wrote:Are you properly adjusting the mask/eraser with the keyframes?

Are you talking about changing the position of the mask using keyframes? If that is the case, should I mask out everything but Sora for each individual movement since it repeats with her just advancing across the screen and save several different masks and insert where necessary, just ereasing the unmasked footage that appears behind her?

I'm just having trouble grasping how to use masks on moving objects. My AE manuel only seems to talk about masking stills or simple shapes, not an anime character walking.

gangstaj8 · Post by **gangstaj8** » Mon May 15, 2006 3:56 am

Krisqo wrote:The walking is repative. In the fifteen seconds, she travels about half way across the screen.

Then you'd want to a create a mask for each frame that changes. Once the motion starts repeating, you just reuse the proper mask by changing it's position with the motion settings. For example, say there's 20 frames that repeat, and every other one changes. That means you'd need to create 10 different masks. Each time the animation cycles through a repeat, you just keep using the same 10 masks, but in a slightly different position in the frame. Lining it up just right can be a bit tricky in Premiere, but maybe AE is more precise, I've never used it.

Krisqo wrote:This is probibly such a nOObie question, but isn't masking the same thing as putting the frame into Photoshop and cutting out what you do not want?

It's pretty similar. They're basically just two methods that yeild the same results. However, certain applications would call for different methods, and some people like one way over the other. For this case, masking will save you some stress because you won't have to simulate the walking motion across the frame through each repeated cycle. The motion is already builty in, you just have to line up the mask properly. Good luck.

Krisqo · Post by **Krisqo** » Mon May 15, 2006 12:01 pm

Okay. That sounds so much bettet than spening weeks removing backgrounds on over 400 individual frames. I'm still trying to understand masking but I think I found this stuff mentioned in my AE User Guide (though its only two pages out of 540). I'll play around for a couple days and if I still can't get it to work, i'll post back here with my results. But only editing a few times, thats sweet.

Krisqo · Post by **Krisqo** » Mon May 15, 2006 8:43 pm

Double post update.

After about 7 and a half hours I was able to mask three seconds of the clip. It looks okay, but is there any way to cover up the bouncing outline?

Zarxrax · Post by **Zarxrax** » Mon May 15, 2006 9:00 pm

In general, its good to mask just INSIDE of the existing outline on the video. Then you can stroke the mask to add back an outline if you wish. The main thing is just doing it accurately. The more accurately and the more time you put into refining your mask, the better its going to look.