A difference keying plugin for Cinelerra

SourceForge.net Logo

This page has been quickly thrown together in order to provide a place for screenshots and video examples. I, for one, almost never download unfamiliar GUI-based programs which do not provide screenshots. With this fact in mind, I thought it might behoove me to post some examples of the plugin interface and output. If you find yourself interested in downloading this plugin, please visit the SourceForge.net project page at:

Most of the shots below show the interface from an older CVS version, which has an unimplemented "Add Frame" button. The interface is in transition right now, please excuse the ugliness :)

Once a key frame has been acquired (currently it must always be the first video frame in the timeline) you can use the sliders to adjust how sensitive DiffKey is to differences in Hue, Saturation, Value, Red, Green, and Blue - relative to the colors in the key frame.  Once having adjusted these sliders to their optimum settings, you can boost the alpha channel for the entire mask by adjusting the visibility threshold, and adjust the transparency threshold to remove faint background noise. The Desaturation threshold cancels out the background color from the partially transparent pixels. This can be useful if motion blur is causing background colors to show through. The resulting dark blur is still less than ideal, but it's far less objectionable than having blue streaks chase your subject around the screen.

This shot shows a normal composite. The output of DiffKey is being sent to another plugin which is applying a blur to the alpha channel (radius set to 4).

Here is the raw input for the composite at left.

This is the same composite without the alpha channel blur. Right now, this blur is clearly a must.

This shot shows the mask which is being generated.

The plugin interface from the 0.4 release.

Here we have isolated only the mask generated by differences in the blue channel.

Apple Quicktime examples
(I've tested these with MPlayer)

Description: Link: Video size: Download size
The source footage source.mov 360x240 1,353,206 bytes
The composited shot composite.mov 360x240 1,619,220 bytes
Source next to composite sidebyside_hires.mov 720x240 2,931,470 bytes
Same as above, aggressively compressed sidebyside_lowres.mov 720x240 866,990 bytes

MPEG-2 Video examples
(Problematic for me - YMMV)

Description: Link: Video size: Download size
The source footage source.mpg 360x240 437,153 bytes
The composited shot composite.mpg 360x240 550,944 bytes
Source next to composite sidebyside.mpg 720x240 933,396 bytes