Custom Quantization Tables using defineValue

Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
Post Reply
cujsmith
Posts: 8
Joined: 2016-10-13T16:18:14-07:00
Authentication code: 1151

Custom Quantization Tables using defineValue

Post by cujsmith » 2016-10-25T08:37:55-07:00

Hello, I think I found a bug. It could be attributed to user error, but I think I've ruled out that possibility.
The problem is in supplying a "quantization-table.xml" I wish to encode with the following QTs in a C++ program:
Luminance Quantization Table
16, 12, 14, 17, 22, 30, 45, 72,
12, 13, 14, 17, 22, 31, 46, 74,
14, 14, 16, 19, 25, 35, 52, 83,
17, 17, 19, 23, 30, 41, 62, 100,
22, 22, 25, 30, 39, 54, 80, 129,
30, 31, 35, 41, 54, 74, 111, 178,
45, 46, 52, 62, 80, 111, 166, 267,
72, 74, 83, 100, 129, 178, 267, 428
Chrominance Quantization Table
17, 18, 22, 31, 50, 92, 193, 465,
18, 19, 24, 33, 54, 98, 207, 498,
22, 24, 29, 41, 66, 120, 253, 609,
31, 33, 41, 57, 92, 169, 355, 854,
50, 54, 66, 92, 148, 271, 570, 1370,
92, 98, 120, 169, 271, 498, 1046, 2516,
193, 207, 253, 355, 570, 1046, 2198, 5289,
465, 498, 609, 854, 1370, 2516, 5289, 12725

This is the c++ code I'm using:

Code: Select all

        image.read( "in.jpg" );
        image.defineValue("jpeg", "q-table", "quantization-table.xml");
        image.write( "out.jpg" );
However, in my "out.jpg" I'm ending up with these QTs:
Luminance Quantization Table
2, 2, 2, 2, 3, 4, 6, 10
2, 2, 2, 2, 3, 4, 6, 10
2, 2, 2, 3, 4, 5, 7, 12
2, 2, 3, 3, 4, 6, 9, 14
3, 3, 4, 4, 5, 8, 11, 18
4, 4, 5, 6, 8, 10, 16, 25
6, 6, 7, 9, 11, 16, 23, 37
10, 10, 12, 14, 18, 25, 37, 60
Chrominance Quantization Table
2, 3, 3, 4, 7, 13, 27, 65
3, 3, 3, 5, 8, 14, 29, 70
3, 3, 4, 6, 9, 17, 35, 85
4, 5, 6, 8, 13, 24, 50 120
7, 8, 9, 13, 21, 38, 80 192
13, 14, 17, 24, 38, 70 146 352
27, 29, 35, 50, 80 146 308 740
65, 70, 85 120 192 352 740 1782

Thanks for the help in advance!

Post Reply