Chroma key?

Post your questions here and we'll all try to help.
GLspace
Met Resolume in a bar the other day
Posts: 11
Joined: Fri Mar 27, 2009 01:11

Chroma key?

Post by GLspace »

Hi!

I"d like to chroma key videol sequences filmed on a blue screen. Is there such a feature in Resolume 3? I've seen that feature in Modul8, but haven't found it yet in Avenue 3.

Thanks!

Guillaume

syzygy
Is taking Resolume on a second date
Posts: 35
Joined: Mon Jan 17, 2005 14:59

Re: Chroma key?

Post by syzygy »

I'm planning on writing a chroma key plugin soon.

I'm still not sure whether to do it as a mixing mode (can be used to mix layers easily but can't have more than one parameter) or as an effect (a bit harder to use for mixing but can have parameters)

At the moment, I'm leaning towards an effect with parameters for key colour, tolerance, edge blending. This could then be applied to a clip or a layer to create an alpha channel based on the keying. Another mixing mode could then be used to fade the keyed layer in and out.

Would that provide what you want?

Dan.

GLspace
Met Resolume in a bar the other day
Posts: 11
Joined: Fri Mar 27, 2009 01:11

Re: Chroma key?

Post by GLspace »

Wow Dan that would be super. Do you think this can be done by next Wednesday? :-P

Actually, I was also eager of getting into FFGL fun and writing it myself. I'm new to Resolume, but my trade is C++/OpenGL/GLSL. Out of curiosity, I should I go about starting that? I have a few gorgeous real time shaders I'd like to port to Resolume.

Best,

G

User avatar
bart
Team Resolume
Posts: 2168
Joined: Wed Sep 29, 2004 10:01
Location: Resolume HQ

Re: Chroma key?

Post by bart »

To get your gorgeous real time shaders to work in Resolume you,ll need to write FreeFrameGL 1.5 plugins :-)

All the info about the API and a zip file with sample code for MSVC and Xcode are all available on the www.freeframe.org website.

Let us know if you run into any problems, we,d love to see your plugins!

GLspace
Met Resolume in a bar the other day
Posts: 11
Joined: Fri Mar 27, 2009 01:11

Re: Chroma key?

Post by GLspace »

Just looked at the FreeFrame code, and everything seems really simple, intuitive, and straightforward. Will definitely move on forward with this. If possible, can you direct me to knowledge about chroma key maths? thanks in advance

G

User avatar
wuzzle
Hasn't felt like this about software in a long time
Posts: 58
Joined: Tue Sep 16, 2008 15:56
Location: Toronto, Canada

Re: Chroma key?

Post by wuzzle »

GLspace wrote:Just looked at the FreeFrame code, and everything seems really simple, intuitive, and straightforward. Will definitely move on forward with this. If possible, can you direct me to knowledge about chroma key maths? thanks in advance

G
http://en.wikipedia.org/wiki/Chroma_key#Programming

Saw some useful code to examine here: http://www.openmash.org/lxr/source/fx/effects/

Another developer working on chroma keying for a package called Cinelerra - Thread here: http://www.mail-archive.com/cinelerra@s ... 06754.html

http://en.wikipedia.org/wiki/Primatte_c ... _Algorithm

Hope there's something useful in there...
VJ Wuzzle
Shakti Collective - Toronto, Canada

User avatar
bart
Team Resolume
Posts: 2168
Joined: Wed Sep 29, 2004 10:01
Location: Resolume HQ

Re: Chroma key?

Post by bart »

Good stuff VJ Wuzzle! Interesting articles.

GLspace
Met Resolume in a bar the other day
Posts: 11
Joined: Fri Mar 27, 2009 01:11

Re: Chroma key?

Post by GLspace »

Massive info! Many thanks!

G

GLspace
Met Resolume in a bar the other day
Posts: 11
Joined: Fri Mar 27, 2009 01:11

Re: Chroma key?

Post by GLspace »

Hello

I've just finished coding a very simple Chroma Key plugin. It kicks out the blue (0,0,255) and makes it alpha = 0.0, alpha = 1.0 otherwise. It works with a GLSL shader. It's quick and dirty, but suits my needs (we do a prematting first).

If anyone's interested in the DLL, let me know, I'll send it to you with love.

G

sleepytom
Hasn't felt like this about software in a long time
Posts: 235
Joined: Fri Sep 12, 2008 11:11
Location: sussex by the sea

Re: Chroma key?

Post by sleepytom »

Hiya
I'd be very interested in seeing this plugin, its always nice to see new people using freeframe :)

If your making FFGL plugins please register on the freeframe community site ( www.community.freeframe.org ) so you can add your plugins to the database, and check your plugins FourCC ID to ensure that it doesn't conflict with any existing plugins.

Best of luck with the plugins, i'm looking forward to seeing what people manage to do with these GPU accelerated effects, some nice realtime particles would make a great source plugin. I hope that we will see more source plugins in FFGL as i'm too lazy to make many clips ;)

cheers
tom

Post Reply