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TwelveMonkeys ImageIO metadata support classes.
/*
* Copyright (c) 2012, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name "TwelveMonkeys" nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.imageio.metadata.jpeg;
import com.twelvemonkeys.lang.Validate;
import javax.imageio.IIOException;
import javax.imageio.ImageIO;
import javax.imageio.plugins.jpeg.JPEGQTable;
import javax.imageio.stream.ImageInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
/**
* Determines an approximate JPEG compression quality value from the quantization tables.
*
* @author Harald Kuhr
* @author last modified by $Author: haraldk$
* @version $Id: JPEGQuality.java,v 1.0 16.02.12 17:07 haraldk Exp$
*/
public final class JPEGQuality {
static final int NUM_QUANT_TABLES = 4; /* Quantization tables are numbered 0..3 */
static final int DCT_SIZE_2 = 64; /* DCT_SIZE squared; # of elements in a block */
/**
* Determines an approximate JPEG compression quality value from the quantization tables.
* The value will be in the range {@code [0...1]}, where {@code 1} is the best possible value.
*
* @param segments a list of JPEG segments containing the DQT quantization tables.
* @return a float in the range {@code [0...1]}, representing the JPEG quality,
* or {@code -1} if the quality can't be determined.
* @throws IIOException if a JPEG format error is found during parsing.
* @throws IOException if an I/O exception occurs during parsing.
*
* @see javax.imageio.plugins.jpeg.JPEGImageWriteParam#setCompressionQuality(float)
* @see JPEG#DQT
*/
public static float getJPEGQuality(final List segments) throws IOException {
int quality = getJPEGQuality(getQuantizationTables(segments));
return quality >= 0 ? quality / 100f : quality;
}
/**
* Determines an approximate JPEG compression quality value from the quantization tables.
* The value will be in the range {@code [0...1]}, where {@code 1} is the best possible value.
*
* @param input an image input stream containing JPEG data.
* @return a float in the range {@code [0...1]}, representing the JPEG quality,
* or {@code -1} if the quality can't be determined.
* @throws IIOException if a JPEG format error is found during parsing.
* @throws IOException if an I/O exception occurs during parsing.
*
* @see javax.imageio.plugins.jpeg.JPEGImageWriteParam#setCompressionQuality(float)
* @see JPEG#DQT
*/
public static float getJPEGQuality(final ImageInputStream input) throws IOException {
return getJPEGQuality(JPEGSegmentUtil.readSegments(input, JPEG.DQT, null));
}
// Adapted from ImageMagick coders/jpeg.c & http://blog.apokalyptik.com/2009/09/16/quality-time-with-your-jpegs/
private static int getJPEGQuality(final int[][] quantizationTables) throws IOException {
// System.err.println("tables: " + Arrays.deepToString(tables));
// TODO: Determine lossless JPEG, it's an entirely different algorithm
int qvalue;
// Determine the JPEG compression quality from the quantization tables.
int sum = 0;
for (int i = 0; i < NUM_QUANT_TABLES; i++) {
if (quantizationTables[i] != null) {
for (int j = 0; j < DCT_SIZE_2; j++) {
sum += quantizationTables[i][j];
}
}
}
int[] hash, sums;
if (quantizationTables[0] != null && quantizationTables[1] != null) {
// TODO: Make constant
hash = new int[] {
1020, 1015, 932, 848, 780, 735, 702, 679, 660, 645,
632, 623, 613, 607, 600, 594, 589, 585, 581, 571,
555, 542, 529, 514, 494, 474, 457, 439, 424, 410,
397, 386, 373, 364, 351, 341, 334, 324, 317, 309,
299, 294, 287, 279, 274, 267, 262, 257, 251, 247,
243, 237, 232, 227, 222, 217, 213, 207, 202, 198,
192, 188, 183, 177, 173, 168, 163, 157, 153, 148,
143, 139, 132, 128, 125, 119, 115, 108, 104, 99,
94, 90, 84, 79, 74, 70, 64, 59, 55, 49,
45, 40, 34, 30, 25, 20, 15, 11, 6, 4,
0
};
sums = new int[] {
32640, 32635, 32266, 31495, 30665, 29804, 29146, 28599, 28104,
27670, 27225, 26725, 26210, 25716, 25240, 24789, 24373, 23946,
23572, 22846, 21801, 20842, 19949, 19121, 18386, 17651, 16998,
16349, 15800, 15247, 14783, 14321, 13859, 13535, 13081, 12702,
12423, 12056, 11779, 11513, 11135, 10955, 10676, 10392, 10208,
9928, 9747, 9564, 9369, 9193, 9017, 8822, 8639, 8458,
8270, 8084, 7896, 7710, 7527, 7347, 7156, 6977, 6788,
6607, 6422, 6236, 6054, 5867, 5684, 5495, 5305, 5128,
4945, 4751, 4638, 4442, 4248, 4065, 3888, 3698, 3509,
3326, 3139, 2957, 2775, 2586, 2405, 2216, 2037, 1846,
1666, 1483, 1297, 1109, 927, 735, 554, 375, 201,
128, 0
};
qvalue = quantizationTables[0][2] + quantizationTables[0][53] + quantizationTables[1][0] + quantizationTables[1][DCT_SIZE_2 - 1];
}
else if (quantizationTables[0] != null) {
// TODO: Make constant
hash = new int[] {
510, 505, 422, 380, 355, 338, 326, 318, 311, 305,
300, 297, 293, 291, 288, 286, 284, 283, 281, 280,
279, 278, 277, 273, 262, 251, 243, 233, 225, 218,
211, 205, 198, 193, 186, 181, 177, 172, 168, 164,
158, 156, 152, 148, 145, 142, 139, 136, 133, 131,
129, 126, 123, 120, 118, 115, 113, 110, 107, 105,
102, 100, 97, 94, 92, 89, 87, 83, 81, 79,
76, 74, 70, 68, 66, 63, 61, 57, 55, 52,
50, 48, 44, 42, 39, 37, 34, 31, 29, 26,
24, 21, 18, 16, 13, 11, 8, 6, 3, 2,
0
};
sums = new int[] {
16320, 16315, 15946, 15277, 14655, 14073, 13623, 13230, 12859,
12560, 12240, 11861, 11456, 11081, 10714, 10360, 10027, 9679,
9368, 9056, 8680, 8331, 7995, 7668, 7376, 7084, 6823,
6562, 6345, 6125, 5939, 5756, 5571, 5421, 5240, 5086,
4976, 4829, 4719, 4616, 4463, 4393, 4280, 4166, 4092,
3980, 3909, 3835, 3755, 3688, 3621, 3541, 3467, 3396,
3323, 3247, 3170, 3096, 3021, 2952, 2874, 2804, 2727,
2657, 2583, 2509, 2437, 2362, 2290, 2211, 2136, 2068,
1996, 1915, 1858, 1773, 1692, 1620, 1552, 1477, 1398,
1326, 1251, 1179, 1109, 1031, 961, 884, 814, 736,
667, 592, 518, 441, 369, 292, 221, 151, 86,
64, 0
};
qvalue = quantizationTables[0][2] + quantizationTables[0][53];
}
else {
return -1;
}
for (int i = 0; i < 100; i++) {
if (qvalue < hash[i] && sum < sums[i]) {
continue;
}
if (qvalue <= hash[i] && sum <= sums[i] || i >= 50) {
return i + 1;
}
break;
}
return -1;
}
public static JPEGQTable[] getQTables(final List segments) throws IOException {
int[][] tables = getQuantizationTables(segments);
List qTables = new ArrayList();
for (int[] table : tables) {
if (table != null) {
qTables.add(new JPEGQTable(table));
}
}
return qTables.toArray(new JPEGQTable[qTables.size()]);
}
private static int[][] getQuantizationTables(final List dqtSegments) throws IOException {
Validate.notNull(dqtSegments, "segments");
int[][] tables = new int[4][];
// JPEG may contain multiple DQT marker segments
for (JPEGSegment segment : dqtSegments) {
if (segment.marker() != JPEG.DQT) {
continue;
}
DataInputStream data = new DataInputStream(segment.data());
int read = 0;
// A single DQT marker segment may contain multiple tables
while (read < segment.length()) {
int qtInfo = data.read();
read++;
// System.err.printf("qtInfo: 0x%02x\n", qtInfo);
int num = qtInfo & 0x0f; // 0-3
int bits = qtInfo >> 4; // 0 == 8 bits, 1 == 16 bits
if (num >= 4) {
throw new IIOException("Bad DQT table index: " + num);
}
else if (tables[num] != null) {
throw new IIOException("Duplicate DQT table index: " + num);
}
if (bits < 0 || bits > 1) {
throw new IIOException("Bad DQT bit info: " + bits);
}
byte[] qtData = new byte[DCT_SIZE_2 * (bits + 1)];
data.readFully(qtData);
read += qtData.length;
tables[num] = new int[DCT_SIZE_2];
// Expand (this is slightly inefficient)
switch (bits) {
case 0:
for (int j = 0, qtDataLength = qtData.length; j < qtDataLength; j++) {
tables[num][j] = (short) (qtData[j] & 0xff);
}
break;
case 1:
for (int j = 0, qtDataLength = qtData.length; j < qtDataLength; j += 2) {
tables[num][j / 2] = (short) ((qtData[j] & 0xff) << 8 | (qtData[j + 1] & 0xff));
}
break;
}
}
}
return tables;
}
public static void main(String[] args) throws IOException {
for (String arg : args) {
float quality = getJPEGQuality(ImageIO.createImageInputStream(new File(arg)));
System.err.println(arg + " quality: " + quality + "/" + (int) (quality * 100));
}
}
}
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