If this is on a Mac the key values are in YUV. The green value is
the lowest in the range (16,16,16) that's why the screen is green to
begin with.<br><br><div><span class="gmail_quote">On 4/24/06, <b class="gmail_sendername">B. Bogart</b> <<a href="mailto:ben@ekran.org">ben@ekran.org</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hey all,<br><br>I'm CCing a local artist, Teresa, who asked me this question.<br><br>In the process of playing with some keying footage she provided I seem<br>unable to make pix_chroma_key actually work in this case...<br>
<br>We have two videos, a figure shot on a green screen (reading value 0, 240,<br>0), and a background to layer the figure into.<br><br>I'm using "value 0 240 0" to select the exact green of the background.<br><br>
Now my understanding means that I should be able to see the green knocked<br>out with a very low range, since it is more or less all the same exact<br>color/shade, but instead I need to provide a very very high "range" to get
<br>a horrid result. I can start to see little bits of the figure with a range<br>of "104 104 104", but going all the way up to "255 255 255" I don't see<br>the whole figure (blacks parts are missing), and I get an approximate 1
<br>pixel green halo around the figure. Some of this is due to compression,<br>but that does not explain how bad this really looks. See attached<br>screenshot of "value 0 240 0" "range 255 255 255"<br>
<br>Note I have sent colorspace RGB to both pix_film's so that I'm using RGB<br>ranges and values.<br><br>It looks to me like the "range" I'm providing is trying to match not the<br>green background, but the figure itself...
<br><br>Since its a good green-screen, and pretty good footage, this should be a<br>cinch to do, but I can't figure it out, after playing with the all the<br>variables, direction, and which video goes to which pix_chroma_key inlet.
<br><br>Please CC Teresa as it is her really trying to figure this out...<br><br>Thanks!<br><br>.b.<br><br><br><br><br>_______________________________________________<br>GEM-dev mailing list<br><a href="mailto:GEM-dev@iem.at">
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