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HDV Prep, YUV or RGB
Hi, I’m shooting HDV (mpeg-2) 24p green screens – I know, don’t! But this is what I have. Anyway, it’s been written that it can be prepared for green screen keying by converting to YUV, blurring the U and V channels, and reconverting to RGB. My questions are these – many writers refer to HDV as 4:1:1 which is based on averaging the chroma in horizontal groups of pixels. They suggest blurring in the horizontal only. However, as I understand it, HDV is actually 4:2:0 which averages the chroma over blocks of pixels (covering more than one scan line). Thus it would seem logical to blur the U and V in both the horizontal and vertical. Am I right? But my bigger question is – why convert to YUV first? I seem to get equivalent results staying in RGB and blurring the R and B channels. Probably I just don’t understand the intricacies of these color sampling regimes and color spaces. Thanks. Dale
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1 Reply
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Hi Dale,
Without getting into the details of color spaces and sub-sampling, there’s an interesting suggestion on the first reply to this thread: https://forums.creativecow.net/archivethread/2/598463.
You might as well give it a try.
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