Non-Blue-Screen Background at DVinfo.net

Aram Rian · November 1st, 2006, 04:33 AM

hi. what would be the best technique for taking certain characters or subjects out of an existing video context and inserting them into a different footage, if those characters and subjects had not been originally shot against a blue/green screen? in other words, how to key out the unnecessary background in the original video, if it doesn't consist of just one colour? thanks.

Logan Bright · November 3rd, 2006, 01:21 PM

You could rotoscope (mask) out the characters and then blur the mask a bit to round off the edges, or perhaps apply a choker to eliminate some jagginess. It will take a long time, especially if there is a lot to do and there is movement in the scene.

Hope you have a lot of patience!

(Of course, there are probably other, better ways, but rotoscoping would be my first bet. Good luck!)

~Loggie B

Aram Rian · November 3rd, 2006, 02:03 PM

at last, someone replied! bless you.
you mean rotoscoping frame by frame like i'd do that in photoshop, for example?

Nick Jushchyshyn · November 3rd, 2006, 02:21 PM

Yup. Rotoscope (drawing a mask frame-by-frame) is usually the best way to handle this.
AE has a rotomask tool that can help a bit, since it is a vector shape that is keyframe animated. This means you don't have to animate every shape for every frame.

Check out Scott Squires Rotoscoping episodes from his Effects Corner podcast for some more background and tips:
http://effectscorner.blogspot.com/20...ng-part-1.html

Don Donatello · November 3rd, 2006, 10:53 PM

rotoscoping wouldn't be frame by frame- depending on the clip ..
with AE/combustion you rotoscope frame 1 .. maybe jump to frame 16 .. then
see how AE/combustion auto adjust the matte for frames 2-15 - if off then maybe you go and fine tune frame 1,8,16 - then see how AE handles 2-6 and 9-15 .. if off you then maybe go and adjust 1/4/8/12/16 which will probably get it right - all depends on how much motion is in the shoot ... if you rotoscope everyframe manually you usually end up with chatter on the edges of matte ...

Aram Rian · November 4th, 2006, 02:25 AM

thanks a lot.
sounds like i need to urgently get a copy of AE.
have only got FCE and AP. any chance of achieving the same results with those apps?

Glenn Chan · November 4th, 2006, 10:23 PM

Try a difference key before you rotoscope. If the difference key doesn't work, use rotoscoping to clean it up.

2- Unfortunately, difference keys don't work too well when the b/g is moving. And you need a clean b/g plate (that's not too hard to make though if you photoshop it together from different frames).

Lee Wilson · November 5th, 2006, 03:29 PM

Quote:

Originally Posted by Glenn Chan

Try a difference key before you rotoscope. If the difference key doesn't work, use rotoscoping to clean it up.

2- Unfortunately, difference keys don't work too well when the b/g is moving. And you need a clean b/g plate (that's not too hard to make though if you photoshop it together from different frames).

Yep! If the camera is locked off (not moving) and the background is also static, then a difference key will pick a moving subject out with some level of success.

November 1st, 2006, 04:33 AM	#1
Aram Rian Regular Crew Join Date: Oct 2006 Location: Birmingham, UK / Yerevan, Armenia Posts: 93	Non-Blue-Screen Background hi. what would be the best technique for taking certain characters or subjects out of an existing video context and inserting them into a different footage, if those characters and subjects had not been originally shot against a blue/green screen? in other words, how to key out the unnecessary background in the original video, if it doesn't consist of just one colour? thanks.

November 3rd, 2006, 02:03 PM	#3
Aram Rian Regular Crew Join Date: Oct 2006 Location: Birmingham, UK / Yerevan, Armenia Posts: 93	at last, someone replied! bless you. you mean rotoscoping frame by frame like i'd do that in photoshop, for example? __________________ "I do detest everything which is not perfectly mutual." Lord Byron

November 3rd, 2006, 02:21 PM	#4
Nick Jushchyshyn Major Player Join Date: Feb 2004 Location: Philadelphia, PA, USA Posts: 548	Yup. Rotoscope (drawing a mask frame-by-frame) is usually the best way to handle this. AE has a rotomask tool that can help a bit, since it is a vector shape that is keyframe animated. This means you don't have to animate every shape for every frame. Check out Scott Squires Rotoscoping episodes from his Effects Corner podcast for some more background and tips: http://effectscorner.blogspot.com/20...ng-part-1.html __________________ Nick Jushchyshyn Matchmoving, Compositing, TD imdb

November 4th, 2006, 02:25 AM	#6
Aram Rian Regular Crew Join Date: Oct 2006 Location: Birmingham, UK / Yerevan, Armenia Posts: 93	thanks a lot. sounds like i need to urgently get a copy of AE. have only got FCE and AP. any chance of achieving the same results with those apps? __________________ "I do detest everything which is not perfectly mutual." Lord Byron

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November 3rd, 2006, 01:21 PM	#2
Logan Bright New Boot Join Date: Mar 2006 Location: Hamilton, Ontario, Canada Posts: 24	You could rotoscope (mask) out the characters and then blur the mask a bit to round off the edges, or perhaps apply a choker to eliminate some jagginess. It will take a long time, especially if there is a lot to do and there is movement in the scene. Hope you have a lot of patience! (Of course, there are probably other, better ways, but rotoscoping would be my first bet. Good luck!) ~Loggie B

November 3rd, 2006, 10:53 PM	#5
Don Donatello Hawaiian Shirt Mogul Join Date: Nov 2001 Location: northern cailfornia Posts: 1,261	rotoscoping wouldn't be frame by frame- depending on the clip .. with AE/combustion you rotoscope frame 1 .. maybe jump to frame 16 .. then see how AE/combustion auto adjust the matte for frames 2-15 - if off then maybe you go and fine tune frame 1,8,16 - then see how AE handles 2-6 and 9-15 .. if off you then maybe go and adjust 1/4/8/12/16 which will probably get it right - all depends on how much motion is in the shoot ... if you rotoscope everyframe manually you usually end up with chatter on the edges of matte ...

November 4th, 2006, 10:23 PM	#7
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	Try a difference key before you rotoscope. If the difference key doesn't work, use rotoscoping to clean it up. 2- Unfortunately, difference keys don't work too well when the b/g is moving. And you need a clean b/g plate (that's not too hard to make though if you photoshop it together from different frames).