Author: paprmh Email: paprmh -> gmail.com Website: http://paprmh.googlepages.com/greenscreen License: gpl Description: A plugin used to do green screen composting. Plugin controls: * greenscreen: turns the plugin on or off. If toggled to yellow, it inverts the mask.. * dv4.1.1: filter to compensate for color info loss due to compression. * Ymin & Ymax: minimum and maximum lumanance values to key out * Uclip & Vclip: blue and red component clip values...basically, the U and V values are how "far" from green they are. * display: this chooses what is output from the plugin: 0)normal composited output. 1)Selection aid, 2) alpha mask, 3) Y (luminance), 4) U ( chroma blue), 5) V (chroma red) * check / ibuf2: selects the background you want to use when keying. Off is a solid color indicated by the color box below, check is a grey checkerboard pattern, and use ibuf2 (yellow) if a second image is attached to the plugin. * edge blur: feathers the edge of the mask with the background * blur: the blur factor around the edges... the scale of this blur is 4x what you see in a node blur. Usually the default setting works well... * radius: this is the radius of the filter for the blur. Again, the default works well here. * info / TMI: print plugin information to the console or (possibly) Too Much Information * spill / spill+: gets rid of green spill in the non keyed areas of the image. You can manually adjust the "respill". If toggled to spill+, respill is automatically determined by the chosen background color * factor: spill reduction strength * Yadj, Uadj, Vadj: use these buttons to adjust the "respill" colors when in spill mode- they are disabled in spill+ mode Just add your greenscreen image sequence or movie strip into the SE and then add the plugin. If you want to use another strip for a composite background, add that strip also, select your green strip, shift-select your background strip and then add the plugin. If you can't use your target background, find an image or use a background color that will be similar to your scene. This not only lets you see how it may eventually look, it also comes in handy for the spill control later. Do not use a sequence strip as your background for now because that will slow down the response of the SE to a crawl while you are adjusting the plugin. You can change to a sequence strip later if you want too. The SE also responds much faster to image strips than movies. The selection process: The plugin works by keying out any pixel that does ALL of the following: * has a lum value between Ymin & Ymax - this helps to keep very dark colors and very light colors * has a U value below the Uclip vlaue - this preserves blue-green colors * has a V value below the Vclip value - this preserves red -green colors This is where display mode 1, selection mode, comes in handy. In this mode you will see which pixels are not keyed and which of the channels are stopping it from being keyed out. * If the luma value of the pixel is Ymax, it adds a light green component to the display. * if pixel U value > Uclip, it adds a blue component to the display. * if pixel V value > Vclip, it adds a red component to the display. Note how the colors mix to indicate that more than 1 channel is active ( white means Ymin & U &V, dark purple means U & V, etc) The easiest way to start is just to adjust each of the sliders until you start to get parts of the background to show up in your display and then back it off a bit. While adjusting your key. it is often helpful to switch back and forth between the normal mask, inverted mask, display 1,and the 3 background options [solid color, check, & ibuf2] so you can see how it affects your key. spill & spill+ control: Spill control is easy. Just toggle spill on and raise the factor value until the green is gone -usually you can just set the factor to 1. Spill control tends to darken parts of the image as it removes the green but the plugin preserves the origional luma value of each pixel also. Usually, spill removal stops there but now you can "respill" your image in 2 different ways to better match the lighting of your new background: spill: If you would like your image to match the new background better, you can now use the Yadj, Uadj, and Vadj levels to change the brightness or color of the spill area . Change the Yadj to affect the overall brightness of the respill. Uadj & Vadj change the blue & red components (YUV colorspace is a bit wierd...you may not get the results you want at first but just play with the controls a bit and you will get the hang of it ). It can be helpful to invert the mask so you can see what spill is doing to the keyed out portions of your clip and and then make adjustments until they are close to the color of your new background spill+: there is also a second toggle ( to yellow ) which will automatically use the background color as the respill target. The Yadj, Uadj, and Vadj controls are disabled in this mode... all you have to do is change the background color to adjust your respill.