From: Hans van der Meer <h.vandermeer@uva.nl>
To: NTG ConTeXt <ntg-context@ntg.nl>
Subject: CMYK colors not as expected
Date: Tue, 28 Jun 2011 14:06:31 +0200 [thread overview]
Message-ID: <F882FA36-B82D-4F5F-9E65-34D4151964EE@uva.nl> (raw)
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I would be pleased to get some advice from "color-knowledgeable people" on the following matter.
In TV-broadcasts there are usually two kinds of subtitles present: Teletext as characters and DVB as pixels. These can be extracted and rendered with Metapost. I have done this, but I am not very satisfied with the colors produced. On the television screen they look bright, when rendered in Metapost they are dull and muddy. The text is barely readable.
As I am fairly sure I did extract the correct bits from the CLUT contained in the stream, I wonder if I am doing something not right at the Metapost side. In the datastream the values given are the most significant 6, 4, 4 and 2 bits of respectively Y, Cr, Cb, T. These are scaled to the values given to Metapost by dividing them by 255.
In the zip one finds the program (ConTeXt MKIV) used for typesetting, an example pixel map with clut, and the output. I would be obliged to get some comments.
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Hans van der Meer
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next reply other threads:[~2011-06-28 12:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-28 12:06 Hans van der Meer [this message]
2011-06-29 6:08 ` luigi scarso
2011-06-29 13:59 ` Taco Hoekwater
2011-06-29 14:10 ` Taco Hoekwater
2011-06-29 8:10 ` Hans Hagen
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