63 lines
2.0 KiB
XML
63 lines
2.0 KiB
XML
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<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE quantization-tables [
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<!ELEMENT quantization-tables (table)+>
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<!ELEMENT table (description , levels)>
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<!ELEMENT description (CDATA)>
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<!ELEMENT levels (CDATA)>
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<!ATTLIST table slot ID #REQUIRED>
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<!ATTLIST levels width CDATA #REQUIRED>
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<!ATTLIST levels height CDATA #REQUIRED>
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<!ATTLIST levels divisor CDATA #REQUIRED>
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]>
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<!--
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JPEG quantization table created by Dr. Nicolas Robidoux, Senior Research
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Scientist at Phase One (www.phaseone.com) for use with 2x2 Chroma
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subsampling and (IJG-style, hence ImageMagick-style) quality level
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around 75.
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It is based on the one recommended in
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Relevance of human vision to JPEG-DCT compression by Stanley A. Klein,
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Amnon D. Silverstein and Thom Carney. In Human Vision, Visual
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Processing and Digital Display III, 1992.
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for 1 minute per pixel viewing.
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Specifying only one table in this xml file has two effects when used with
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the ImageMagick option
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-define jpeg:q-table=PATH/TO/THIS/FILE
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1) This quantization table is automatically used for all three channels;
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2) Only one copy is embedded in the JPG file, which saves a few bits
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(only worthwhile for very small thumbnails).
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-->
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<quantization-tables>
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<table slot="0" alias="luma">
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<description>Luma Quantization Table</description>
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<levels width="8" height="8" divisor="1">
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16, 16, 16, 18, 25, 37, 56, 85,
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16, 17, 20, 27, 34, 40, 53, 75,
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16, 20, 24, 31, 43, 62, 91, 135,
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18, 27, 31, 40, 53, 74, 106, 156,
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25, 34, 43, 53, 69, 94, 131, 189,
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37, 40, 62, 74, 94, 124, 169, 238,
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56, 53, 91, 106, 131, 169, 226, 311,
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85, 75, 135, 156, 189, 238, 311, 418
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</levels>
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</table>
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<!--
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If you want to use a different quantization table for Chroma (say), just add
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<table slot="1" alias="chroma">
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<description>Chroma Quantization Table</description>
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INSERT 64 POSITIVE INTEGERS HERE, COMMA-SEPARATED
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</levels>
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</table>
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here (but outside of these comments).
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-->
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</quantization-tables>
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