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Support for decoding JPEG quality setting based on DQT tables.
This commit is contained in:
Harald Kuhr
parent
0307237852
commit
93e57306d5
@ -36,14 +36,17 @@ package com.twelvemonkeys.imageio.metadata.jpeg;
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* @version $Id: JPEG.java,v 1.0 11.02.11 15.51 haraldk Exp$
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*/
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public interface JPEG {
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/** Start of Image segment marker. */
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/** Start of Image segment marker (SOI). */
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int SOI = 0xFFD8;
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/** End of Image segment marker. */
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/** End of Image segment marker (EOI). */
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int EOI = 0xFFD9;
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/** Start of Stream segment marker. */
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/** Start of Stream segment marker (SOS). */
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int SOS = 0xFFDA;
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// App segment markers (APPn)
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/** Define Quantization Tables segment marker (DQT). */
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int DQT = 0xFFDB;
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// App segment markers (APPn).
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int APP0 = 0xFFE0;
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int APP1 = 0xFFE1;
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int APP2 = 0xFFE2;
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@ -61,7 +64,7 @@ public interface JPEG {
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int APP14 = 0xFFEE;
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int APP15 = 0xFFEF;
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// Start of Frame segment markers (SOFn)
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// Start of Frame segment markers (SOFn).
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int SOF0 = 0xFFC0;
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int SOF1 = 0xFFC1;
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int SOF2 = 0xFFC2;
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@ -76,7 +79,7 @@ public interface JPEG {
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int SOF14 = 0xFFCE;
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int SOF15 = 0xFFCF;
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// TODO: Known/Important APPn markers
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// TODO: Known/Important APPn marker identifiers
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// "JFIF" APP0
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// "JFXX" APP0
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// "Exif" APP1
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@ -0,0 +1,245 @@
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/*
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* Copyright (c) 2012, Harald Kuhr
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name "TwelveMonkeys" nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package com.twelvemonkeys.imageio.metadata.jpeg;
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import javax.imageio.IIOException;
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import javax.imageio.ImageIO;
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import javax.imageio.stream.ImageInputStream;
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import java.io.DataInputStream;
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import java.io.File;
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import java.io.IOException;
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import java.util.List;
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/**
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* JPEGQuality
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*
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* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
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* @author last modified by $Author: haraldk$
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* @version $Id: JPEGQuality.java,v 1.0 16.02.12 17:07 haraldk Exp$
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*/
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public class JPEGQuality {
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// TODO: Something for the metadata.jpeg package?
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// TODO: Make a test that verifies that the values are in line with parameter set to JPEGImageWriter
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static final int NUM_QUANT_TABLES = 4; /* Quantization tables are numbered 0..3 */
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static final int DCT_SIZE_2 = 64; /* DCT_SIZE squared; # of elements in a block */
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public static void main(String[] args) throws IOException {
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for (String arg : args) {
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float quality = getJPEGQuality(ImageIO.createImageInputStream(new File(arg)));
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System.err.println(arg + " quality: " + quality + "/" + (int) (quality * 100));
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}
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}
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// TODO: Do we want 1-100 (%) or 0-1 (float) as result? The latter is more in line with the quality parameter given
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// to the writer (in JPEGImageWriteParam). OTOH, it should also be possible to instruct the writer to use the tables
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// from the original image directly, which would provide more "accurate" results.
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/**
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* Determines an approximate JPEG compression quality value from the quantization tables.
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* The value will be in the range {@code [0...1]}, where {@code 1} is the best possible value.
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*
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*
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* @param segments a list of JPEG segments containing the DQT quantization tables.
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* @return a float in the range {@code [0...1]}, representing the JPEG quality,
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* or {@code -1} if the quality can't be determined.
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* @throws IIOException if a JPEG format error is found during parsing.
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* @throws IOException if an I/O exception occurs during parsing.
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*
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* @see JPEG#DQT
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*/
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public static float getJPEGQuality(final List<JPEGSegment> segments) throws IOException {
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return getJPEGQuality(getQuantizationTables(segments)) / 100f;
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}
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public static float getJPEGQuality(final ImageInputStream input) throws IOException {
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return getJPEGQuality(JPEGSegmentUtil.readSegments(input, JPEG.DQT, null));
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}
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// Adapted from ImageMagick coders/jpeg.c & http://blog.apokalyptik.com/2009/09/16/quality-time-with-your-jpegs/
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private static int getJPEGQuality(final short[][] quantizationTables) throws IOException {
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// System.err.println("tables: " + Arrays.deepToString(tables));
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// TODO: Determine lossless JPEG
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// if (lossless) {
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// return 100; // TODO: Sums can be 100... Is lossless not 100?
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// }
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int qvalue;
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// Determine the JPEG compression quality from the quantization tables.
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int sum = 0;
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for (int i = 0; i < NUM_QUANT_TABLES; i++) {
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if (quantizationTables[i] != null) {
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for (int j = 0; j < DCT_SIZE_2; j++) {
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sum += quantizationTables[i][j];
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}
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}
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}
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int[] hash, sums;
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if (quantizationTables[0] != null && quantizationTables[1] != null) {
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// TODO: Make constant
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hash = new int[] {
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1020, 1015, 932, 848, 780, 735, 702, 679, 660, 645,
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632, 623, 613, 607, 600, 594, 589, 585, 581, 571,
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555, 542, 529, 514, 494, 474, 457, 439, 424, 410,
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397, 386, 373, 364, 351, 341, 334, 324, 317, 309,
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299, 294, 287, 279, 274, 267, 262, 257, 251, 247,
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243, 237, 232, 227, 222, 217, 213, 207, 202, 198,
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192, 188, 183, 177, 173, 168, 163, 157, 153, 148,
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143, 139, 132, 128, 125, 119, 115, 108, 104, 99,
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94, 90, 84, 79, 74, 70, 64, 59, 55, 49,
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45, 40, 34, 30, 25, 20, 15, 11, 6, 4,
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0
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};
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sums = new int[] {
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32640, 32635, 32266, 31495, 30665, 29804, 29146, 28599, 28104,
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27670, 27225, 26725, 26210, 25716, 25240, 24789, 24373, 23946,
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23572, 22846, 21801, 20842, 19949, 19121, 18386, 17651, 16998,
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16349, 15800, 15247, 14783, 14321, 13859, 13535, 13081, 12702,
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12423, 12056, 11779, 11513, 11135, 10955, 10676, 10392, 10208,
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9928, 9747, 9564, 9369, 9193, 9017, 8822, 8639, 8458,
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8270, 8084, 7896, 7710, 7527, 7347, 7156, 6977, 6788,
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6607, 6422, 6236, 6054, 5867, 5684, 5495, 5305, 5128,
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4945, 4751, 4638, 4442, 4248, 4065, 3888, 3698, 3509,
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3326, 3139, 2957, 2775, 2586, 2405, 2216, 2037, 1846,
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1666, 1483, 1297, 1109, 927, 735, 554, 375, 201,
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128, 0
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};
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qvalue = quantizationTables[0][2] + quantizationTables[0][53] + quantizationTables[1][0] + quantizationTables[1][DCT_SIZE_2 - 1];
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}
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else if (quantizationTables[0] != null) {
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// TODO: Make constant
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hash = new int[] {
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510, 505, 422, 380, 355, 338, 326, 318, 311, 305,
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300, 297, 293, 291, 288, 286, 284, 283, 281, 280,
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279, 278, 277, 273, 262, 251, 243, 233, 225, 218,
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211, 205, 198, 193, 186, 181, 177, 172, 168, 164,
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158, 156, 152, 148, 145, 142, 139, 136, 133, 131,
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129, 126, 123, 120, 118, 115, 113, 110, 107, 105,
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102, 100, 97, 94, 92, 89, 87, 83, 81, 79,
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76, 74, 70, 68, 66, 63, 61, 57, 55, 52,
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50, 48, 44, 42, 39, 37, 34, 31, 29, 26,
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24, 21, 18, 16, 13, 11, 8, 6, 3, 2,
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0
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};
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sums = new int[] {
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16320, 16315, 15946, 15277, 14655, 14073, 13623, 13230, 12859,
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12560, 12240, 11861, 11456, 11081, 10714, 10360, 10027, 9679,
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9368, 9056, 8680, 8331, 7995, 7668, 7376, 7084, 6823,
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6562, 6345, 6125, 5939, 5756, 5571, 5421, 5240, 5086,
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4976, 4829, 4719, 4616, 4463, 4393, 4280, 4166, 4092,
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3980, 3909, 3835, 3755, 3688, 3621, 3541, 3467, 3396,
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3323, 3247, 3170, 3096, 3021, 2952, 2874, 2804, 2727,
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2657, 2583, 2509, 2437, 2362, 2290, 2211, 2136, 2068,
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1996, 1915, 1858, 1773, 1692, 1620, 1552, 1477, 1398,
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1326, 1251, 1179, 1109, 1031, 961, 884, 814, 736,
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667, 592, 518, 441, 369, 292, 221, 151, 86,
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64, 0
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};
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qvalue = quantizationTables[0][2] + quantizationTables[0][53];
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}
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else {
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return -1;
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}
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for (int i = 0; i < 100; i++) {
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if (qvalue < hash[i] && sum < sums[i]) {
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continue;
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}
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if (qvalue <= hash[i] && sum <= sums[i] || i >= 50) {
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return i + 1;
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}
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break;
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}
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return -1;
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}
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private static short[][] getQuantizationTables(List<JPEGSegment> dqtSegments) throws IOException {
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short[][] tables = new short[4][];
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// JPEG may contain multiple DQT marker segments
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for (JPEGSegment segment : dqtSegments) {
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if (segment.marker() != JPEG.DQT) {
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continue;
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}
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DataInputStream data = new DataInputStream(segment.data());
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int read = 0;
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// A single DQT marker segment may contain multiple tables
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while (read < segment.length()) {
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int qtInfo = data.read();
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read++;
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// System.err.printf("qtInfo: 0x%02x\n", qtInfo);
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int num = qtInfo & 0x0f; // 0-3
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int bits = qtInfo >> 4; // 0 == 8 bits, 1 == 16 bits
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if (num >= 4) {
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throw new IIOException("Bad DQT table index: " + num);
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}
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else if (tables[num] != null) {
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throw new IIOException("Duplicate DQT table index: " + num);
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}
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if (bits > 1) {
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throw new IIOException("Bad DQT bit info: " + bits);
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}
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byte[] qtData = new byte[DCT_SIZE_2 * (bits + 1)];
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data.readFully(qtData);
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read += qtData.length;
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tables[num] = new short[DCT_SIZE_2];
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// Expand (this is slightly inefficient)
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switch (bits) {
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case 0:
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for (int j = 0, qtDataLength = qtData.length; j < qtDataLength; j++) {
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tables[num][j] = (short) (qtData[j] & 0xff);
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}
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break;
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case 1:
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for (int j = 0, qtDataLength = qtData.length; j < qtDataLength; j += 2) {
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tables[num][j / 2] = (short) ((qtData[j] & 0xff) << 8 | (qtData[j + 1] & 0xff));
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}
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break;
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}
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}
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}
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return tables;
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}
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}
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@ -41,6 +41,8 @@ import java.io.*;
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import java.nio.charset.Charset;
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import java.util.*;
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import static com.twelvemonkeys.lang.Validate.notNull;
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/**
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* JPEGSegmentUtil
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*
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@ -87,7 +89,7 @@ public final class JPEGSegmentUtil {
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* @see #ALL_IDS
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*/
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public static List<JPEGSegment> readSegments(final ImageInputStream stream, final Map<Integer, List<String>> segmentIdentifiers) throws IOException {
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readSOI(stream);
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readSOI(notNull(stream, "stream"));
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List<JPEGSegment> segments = Collections.emptyList();
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