Apple MA434Z/A User Manual - Page 698

Although the information in video is transferred from the YUV colorspace into the RGB colorspace, you can still examine the original YUV channels. Attach a Color-ColorSpace node to the FileIn and set the outSpace to be YUV. With the pointer over the Viewer, press the R, G, and B keys to look at the new YUV channels. Y (luminance) U (Cr, or r/g difference) V (Cb, or b/g difference) As you can now see, the luminance channel gets all of the necessary information, since the human eye is more susceptible to differences in luminance than hue. But the two color channels display significant artifacts. Here are two methods you can use to help you pull better keys from DV footage: To correct a DV key (method 1): 1 Attach a ColorSpace node to the FileIn node containing the DV footage. 2 Set the outSpace parameter of the ColorSpace node to YUV. The colors in the image radically change, but don't worry, this is only temporary. 3 Attach a Blur node to the output of the ColorSpace node. 4 In the Blur node's channels parameter, blur only the U and V channels by switching the channels from rgba to gb. 5 Blur the isolated gb channels by adjusting the xPixels parameter by approximately 8, and adjusting the yPixels parameter independently by a much smaller value, approximately 1 pixel. 6 Attach a second ColorSpace node to the output of the Blur node, then set the inSpace parameter to YUV and keep the outSpace parameter set to RGB. 698 Chapter 24 Keying