1 <?xml version="1.0" encoding="ISO-8859-1"?> 2 <!DOCTYPE quantization-tables [ 3 <!ELEMENT quantization-tables (table)> 4 <!ATTLIST quantization-tables xmlns CDATA #FIXED ""> 5 <!ELEMENT table (description , levels)> 6 <!ATTLIST table xmlns CDATA #FIXED ""> 7 <!ATTLIST table alias NMTOKEN #REQUIRED> 8 <!ATTLIST table slot CDATA #REQUIRED> 9 <!ELEMENT description (#PCDATA)> 10 <!ATTLIST description xmlns CDATA #FIXED ""> 11 <!ELEMENT levels (#PCDATA)> 12 <!ATTLIST levels xmlns CDATA #FIXED ""> 13 <!ATTLIST levels divisor CDATA #REQUIRED> 14 <!ATTLIST levels height CDATA #REQUIRED> 15 <!ATTLIST levels width CDATA #REQUIRED> 16 ]> 17 <!-- 18 JPEG quantization table created by Dr. Nicolas Robidoux, Senior Research 19 Scientist at Phase One (www.phaseone.com) for use with 2x2 Chroma 20 subsampling and (IJG-style, hence ImageMagick-style) quality level 21 around 75. 22 23 It is based on the one recommended in 24 25 Relevance of human vision to JPEG-DCT compression by Stanley A. Klein, 26 Amnon D. Silverstein and Thom Carney. In Human Vision, Visual 27 Processing and Digital Display III, 1992. 28 29 for 1 minute per pixel viewing. 30 31 Specifying only one table in this xml file has two effects when used with 32 the ImageMagick option 33 34 -define jpeg:q-table=PATH/TO/THIS/FILE 35 36 1) This quantization table is automatically used for all three channels; 37 38 2) Only one copy is embedded in the JPG file, which saves a few bits 39 (only worthwhile for very small thumbnails). 40 --> 41 <quantization-tables> 42 <table slot="0" alias="luma"> 43 <description>Luma Quantization Table</description> 44 <levels width="8" height="8" divisor="1"> 45 16, 16, 16, 18, 25, 37, 56, 85, 46 16, 17, 20, 27, 34, 40, 53, 75, 47 16, 20, 24, 31, 43, 62, 91, 135, 48 18, 27, 31, 40, 53, 74, 106, 156, 49 25, 34, 43, 53, 69, 94, 131, 189, 50 37, 40, 62, 74, 94, 124, 169, 238, 51 56, 53, 91, 106, 131, 169, 226, 311, 52 85, 75, 135, 156, 189, 238, 311, 418 53 </levels> 54 </table> 55 <!-- 56 If you want to use a different quantization table for Chroma, for example, 57 just add: 58 59 <table slot="1" alias="chroma"> 60 <description>Chroma Quantization Table</description> 61 INSERT 64 POSITIVE INTEGERS HERE, COMMA-SEPARATED 62 </levels> 63 </table> 64 65 here (but outside of these comments). 66 --> 67 </quantization-tables> 68 69
