更改.png以使用JpegImagesToMovie.java
我正在使用JpegImagesToMovie.java将图像转换为.mov文件。我想知道无论如何我都可以编辑它来处理.png文件，因为视频的质量不是很好，改变它会改善它。
ImageIO.write(img, "png", new File("C:\\Users\\user\\Desktop\\tmp\\" + System.currentTimeMillis() + ".png"));
ImageIO.write(img, "jpeg", new File("C:\\Users\\user\\Desktop\\tmp\\" + System.currentTimeMillis() + ".png"));
ImageIO.write(img, "png", new File("C:\\Users\\user\\Desktop\\tmp\\" + System.currentTimeMillis() + ".jpeg"));
所有这三个都会产生一个视频（通过程序没有错误），但视频不会播放图像只是打开和完成。
我也尝试过编辑JpegImagesToMovie.java
if (!filePath.toLowerCase().endsWith(".png") && !filePath.toLowerCase().endsWith(".png")) {
continue;
但那不起作用，我找不到其他地方可以编辑。我怎样才能使用.png图像？
最新更新：
这是我更新的JpegImagesToMovies类
包枫;
/*
* @(#)JpegImagesToMovie.java 1.3 01/03/13
*
* Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.io.*;
import java.util.*;
import java.awt.Dimension;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.media.*;
import javax.media.control.*;
import javax.media.protocol.*;
import javax.media.datasink.*;
import javax.media.format.RGBFormat;
import javax.media.format.VideoFormat;
/**
* This program takes a list of JPEG image files and convert them into a
* QuickTime movie.
*/
public class JpegImagesToMovie implements ControllerListener, DataSinkListener {
static private Vector<String> getImageFilesPathsVector(
String imagesFolderPath) {
File imagesFolder = new File(imagesFolderPath);
String[] imageFilesArray = imagesFolder.list();
Vector<String> imageFilesPathsVector = new Vector<String>();
for (String imageFileName : imageFilesArray) {
if (!imageFileName.toLowerCase().endsWith("png"))
continue;
imageFilesPathsVector.add(imagesFolder.getAbsolutePath()
+ File.separator + imageFileName);
}
return imageFilesPathsVector;
}
public boolean doIt(int width, int height, int frameRate,
Vector<String> inFiles, MediaLocator outML) {
ImageDataSource ids = new ImageDataSource(width, height, frameRate,
inFiles);
Processor p;
try {
System.err
.println("- create processor for the image datasource ...");
p = Manager.createProcessor(ids);
} catch (Exception e) {
System.err
.println("Yikes! Cannot create a processor from the data source.");
return false;
}
p.addControllerListener(this);
// Put the Processor into configured state so we can set
// some processing options on the processor.
p.configure();
if (!waitForState(p, Processor.Configured)) {
System.err.println("Failed to configure the processor.");
return false;
}
// Set the output content descriptor to QuickTime.
p.setContentDescriptor(new ContentDescriptor(
FileTypeDescriptor.QUICKTIME));// FileTypeDescriptor.MSVIDEO
// Query for the processor for supported formats.
// Then set it on the processor.
TrackControl tcs[] = p.getTrackControls();
Format f[] = tcs[0].getSupportedFormats();
if (f == null || f.length <= 0) {
System.err.println("The mux does not support the input format: "
+ tcs[0].getFormat());
return false;
}
tcs[0].setFormat(f[0]);
System.err.println("Setting the track format to: " + f[0]);
// We are done with programming the processor. Let's just
// realize it.
p.realize();
if (!waitForState(p, Controller.Realized)) {
System.err.println("Failed to realize the processor.");
return false;
}
// Now, we'll need to create a DataSink.
DataSink dsink;
if ((dsink = createDataSink(p, outML)) == null) {
System.err
.println("Failed to create a DataSink for the given output MediaLocator: "
+ outML);
return false;
}
dsink.addDataSinkListener(this);
fileDone = false;
System.err.println("start processing...");
// OK, we can now start the actual transcoding.
try {
p.start();
dsink.start();
} catch (IOException e) {
System.err.println("IO error during processing");
return false;
}
// Wait for EndOfStream event.
waitForFileDone();
// Cleanup.
try {
dsink.close();
} catch (Exception e) {
}
p.removeControllerListener(this);
System.err.println("...done processing.");
return true;
}
/**
* Create the DataSink.
*/
DataSink createDataSink(Processor p, MediaLocator outML) {
DataSource ds;
if ((ds = p.getDataOutput()) == null) {
System.err
.println("Something is really wrong: the processor does not have an output DataSource");
return null;
}
DataSink dsink;
try {
System.err.println("- create DataSink for: " + outML);
dsink = Manager.createDataSink(ds, outML);
dsink.open();
} catch (Exception e) {
System.err.println("Cannot create the DataSink: " + e);
return null;
}
return dsink;
}
Object waitSync = new Object();
boolean stateTransitionOK = true;
/**
* Block until the processor has transitioned to the given state. Return
* false if the transition failed.
*/
boolean waitForState(Processor p, int state) {
synchronized (waitSync) {
try {
while (p.getState() < state && stateTransitionOK)
waitSync.wait();
} catch (Exception e) {
}
}
return stateTransitionOK;
}
/**
* Controller Listener.
*/
public void controllerUpdate(ControllerEvent evt) {
if (evt instanceof ConfigureCompleteEvent
|| evt instanceof RealizeCompleteEvent
|| evt instanceof PrefetchCompleteEvent) {
synchronized (waitSync) {
stateTransitionOK = true;
waitSync.notifyAll();
}
} else if (evt instanceof ResourceUnavailableEvent) {
synchronized (waitSync) {
stateTransitionOK = false;
waitSync.notifyAll();
}
} else if (evt instanceof EndOfMediaEvent) {
evt.getSourceController().stop();
evt.getSourceController().close();
}
}
Object waitFileSync = new Object();
boolean fileDone = false;
boolean fileSuccess = true;
/**
* Block until file writing is done.
*/
boolean waitForFileDone() {
synchronized (waitFileSync) {
try {
while (!fileDone)
waitFileSync.wait();
} catch (Exception e) {
}
}
return fileSuccess;
}
/**
* Event handler for the file writer.
*/
public void dataSinkUpdate(DataSinkEvent evt) {
if (evt instanceof EndOfStreamEvent) {
synchronized (waitFileSync) {
fileDone = true;
waitFileSync.notifyAll();
}
} else if (evt instanceof DataSinkErrorEvent) {
synchronized (waitFileSync) {
fileDone = true;
fileSuccess = false;
waitFileSync.notifyAll();
}
}
}
public static void main(String args[]) {
// changed this method a bit
if (args.length == 0)
prUsage();
// Parse the arguments.
int i = 0;
int width = -1, height = -1, frameRate = -1;
Vector<String> inputFiles = new Vector<String>();
String rootDir = null;
String outputURL = null;
while (i < args.length) {
if (args[i].equals("-w")) {
i++;
if (i >= args.length)
prUsage();
width = new Integer(args[i]).intValue();
} else if (args[i].equals("-h")) {
i++;
if (i >= args.length)
prUsage();
height = new Integer(args[i]).intValue();
} else if (args[i].equals("-f")) {
i++;
if (i >= args.length)
prUsage();
// new Integer(args[i]).intValue();
frameRate = Integer.parseInt(args[i]);
} else if (args[i].equals("-o")) {
i++;
if (i >= args.length)
prUsage();
outputURL = args[i];
} else if (args[i].equals("-i")) {
i++;
if (i >= args.length)
prUsage();
rootDir = args[i];
} else {
System.out.println(".");
prUsage();
}
i++;
}
if (rootDir == null) {
System.out
.println("Since no input (-i) forder provided, assuming this JAR is inside JPEGs folder.");
rootDir = (new File(".")).getAbsolutePath();
}
inputFiles = getImageFilesPathsVector(rootDir);
if (inputFiles.size() == 0)
prUsage();
if (outputURL == null) {
outputURL = (new File(rootDir)).getAbsolutePath() + File.separator
+ "pngs2movie.mov";
}
if (!outputURL.toLowerCase().startsWith("file:///")) {
outputURL = "file:///" + outputURL;
}
// Check for output file extension.
if (!outputURL.toLowerCase().endsWith(".mov")) {
prUsage();
outputURL += ".mov";
System.out
.println("outputURL should be ending with mov. Making this happen.\nNow outputURL is: "
+ outputURL);
}
if (width < 0 || height < 0) {
prUsage();
System.out.println("Trying to guess movie size from first image");
BufferedImage firstImageInFolder = getFirstImageInFolder(rootDir);
width = firstImageInFolder.getWidth();
height = firstImageInFolder.getHeight();
System.out.println("width = " + width);
System.out.println("height = " + height);
}
// Check the frame rate.
if (frameRate < 1)
frameRate = 30;
// Generate the output media locators.
MediaLocator oml;
if ((oml = createMediaLocator(outputURL)) == null) {
System.err.println("Cannot build media locator from: " + outputURL);
System.exit(0);
}
JpegImagesToMovie imageToMovie = new JpegImagesToMovie();
imageToMovie.doIt(width, height, frameRate, inputFiles, oml);
System.exit(0);
}
private static BufferedImage getFirstImageInFolder(String rootDir) {
File rootFile = new File(rootDir);
String[] list = (rootFile).list();
BufferedImage bufferedImage = null;
for (String filePath : list) {
if (!filePath.toLowerCase().endsWith(".png")
&& !filePath.toLowerCase().endsWith(".png")) {
continue;
}
try {
bufferedImage = ImageIO.read(new File(rootFile
.getAbsoluteFile() + File.separator + filePath));
break;
} catch (IOException e) {
e.printStackTrace();
}
}
return bufferedImage;
}
static void prUsage() {
System.err
.println("Usage: java JpegImagesToMovie [-w <width>] [-h <height>] [-f <frame rate>] [-o <output URL>] -i <input JPEG files dir Path>");
// System.exit(-1);
}
/**
* Create a media locator from the given string.
*/
@SuppressWarnings("unused")
public static MediaLocator createMediaLocator(String url) {
MediaLocator ml;
if (url.indexOf(":") > 0 && (ml = new MediaLocator(url)) != null)
return ml;
if (url.startsWith(File.separator)) {
if ((ml = new MediaLocator("file:" + url)) != null)
return ml;
} else {
String file = "file:" + System.getProperty("user.dir")
+ File.separator + url;
if ((ml = new MediaLocator(file)) != null)
return ml;
}
return null;
}
// /////////////////////////////////////////////
//
// Inner classes.
// /////////////////////////////////////////////
/**
* A DataSource to read from a list of JPEG image files and turn that into a
* stream of JMF buffers. The DataSource is not seekable or positionable.
*/
class ImageDataSource extends PullBufferDataSource {
ImageSourceStream streams[];
ImageDataSource(int width, int height, int frameRate,
Vector<String> images) {
streams = new ImageSourceStream[1];
streams[0] = new PngImageSourceStream(width, height, frameRate, images);
}
public void setLocator(MediaLocator source) {
}
public MediaLocator getLocator() {
return null;
}
/**
* Content type is of RAW since we are sending buffers of video frames
* without a container format.
*/
public String getContentType() {
return ContentDescriptor.RAW;
}
public void connect() {
}
public void disconnect() {
}
public void start() {
}
public void stop() {
}
/**
* Return the ImageSourceStreams.
*/
public PullBufferStream[] getStreams() {
return streams;
}
/**
* We could have derived the duration from the number of frames and
* frame rate. But for the purpose of this program, it's not necessary.
*/
public Time getDuration() {
return DURATION_UNKNOWN;
}
public Object[] getControls() {
return new Object[0];
}
public Object getControl(String type) {
return null;
}
}
/**
* The source stream to go along with ImageDataSource.
*/
class ImageSourceStream implements PullBufferStream {
Vector<String> images;
int width, height;
VideoFormat format;
int nextImage = 0; // index of the next image to be read.
boolean ended = false;
public ImageSourceStream(int width, int height, int frameRate,
Vector<String> images) {
this.width = width;
this.height = height;
this.images = images;
format = new VideoFormat(VideoFormat.JPEG, new Dimension(width,
height), Format.NOT_SPECIFIED, Format.byteArray,
(float) frameRate);
}
/**
* We should never need to block assuming data are read from files.
*/
public boolean willReadBlock() {
return false;
}
/**
* This is called from the Processor to read a frame worth of video
* data.
*/
public void read(Buffer buf) throws IOException {
// Check if we've finished all the frames.
if (nextImage >= images.size()) {
// We are done. Set EndOfMedia.
System.err.println("Done reading all images.");
buf.setEOM(true);
buf.setOffset(0);
buf.setLength(0);
ended = true;
return;
}
String imageFile = (String) images.elementAt(nextImage);
nextImage++;
System.err.println(" - reading image file: " + imageFile);
// Open a random access file for the next image.
RandomAccessFile raFile;
raFile = new RandomAccessFile(imageFile, "r");
byte data[] = null;
// Check the input buffer type & size.
if (buf.getData() instanceof byte[])
data = (byte[]) buf.getData();
// Check to see the given buffer is big enough for the frame.
if (data == null || data.length < raFile.length()) {
data = new byte[(int) raFile.length()];
buf.setData(data);
}
// Read the entire JPEG image from the file.
raFile.readFully(data, 0, (int) raFile.length());
System.err.println(" read " + raFile.length() + " bytes.");
buf.setOffset(0);
buf.setLength((int) raFile.length());
buf.setFormat(format);
buf.setFlags(buf.getFlags() | Buffer.FLAG_KEY_FRAME);
// Close the random access file.
raFile.close();
}
/**
* Return the format of each video frame. That will be JPEG.
*/
public Format getFormat() {
return format;
}
public ContentDescriptor getContentDescriptor() {
return new ContentDescriptor(ContentDescriptor.RAW);
}
public long getContentLength() {
return 0;
}
public boolean endOfStream() {
return ended;
}
public Object[] getControls() {
return new Object[0];
}
public Object getControl(String type) {
return null;
}
}
class PngImageSourceStream extends ImageSourceStream {
public PngImageSourceStream(int width, int height, int frameRate, Vector<String> images) {
super(width, height, frameRate, images);
// configure the new format as RGB format
format = new RGBFormat(new Dimension(width, height), Format.NOT_SPECIFIED, Format.byteArray, frameRate,
24, // 24 bits per pixel
1, 2, 3); // red, green and blue masks when data are in the form of byte[]
}
public void read(Buffer buf) throws IOException {
// Check if we've finished all the frames.
if (nextImage >= images.size()) {
// We are done. Set EndOfMedia.
System.err.println("Done reading all images.");
buf.setEOM(true);
buf.setOffset(0);
buf.setLength(0);
ended = true;
return;
}
String imageFile = (String) images.elementAt(nextImage);
nextImage++;
System.err.println(" - reading image file: " + imageFile);
// read the PNG image
BufferedImage image = ImageIO.read( new File(imageFile) );
Dimension size = format.getSize();
// convert 32-bit RGBA to 24-bit RGB
byte[] imageData = convertTo24Bit(image.getRaster().getPixels(0, 0, size.width, size.height, (int[]) null));
buf.setData(imageData);
System.err.println(" read " + imageData.length + " bytes.");
buf.setOffset(0);
buf.setLength(imageData.length);
buf.setFormat(format);
buf.setFlags(buf.getFlags() | Buffer.FLAG_KEY_FRAME);
}
private void convertIntByteToByte(int[] src, int srcIndex, byte[] out, int outIndex) {
// Note: the int[] returned by bufferedImage.getRaster().getPixels() is an int[]
// where each int is the value for one color i.e. the first 4 ints contain the RGBA values for the first pixel
int r = src[srcIndex];
int g = src[srcIndex+1];
int b = src[srcIndex+2];
out[outIndex] = (byte) (r & 0xFF);
out[outIndex+1] = (byte) (g & 0xFF);
out[outIndex+2] = (byte) (b & 0xFF);
}
private byte[] convertTo24Bit(int[] input) {
int dataLength = input.length;
byte[] convertedData = new byte[ dataLength * 3 / 4 ];
// for every 4 int values of the original array (RGBA) write 3
// bytes (RGB) to the output array
for (int i = 0, j = 0; i < dataLength; i+=4, j+=3) {
convertIntByteToByte(input, i, convertedData, j);
}
return convertedData;
}
}
}
我在主方法
中使用以下调用制作视频r.makeVideo("Video.mov");
这就是那种方法。
public void makeVideo (String movFile) throws MalformedURLException {
JpegImagesToMovie imageToMovie = new JpegImagesToMovie();
Vector<String> imgList = new Vector <String>();
File f = new File("C:\\Users\\user\\Desktop\\tmp\\");
File[] fileList = f.listFiles();
for (int i = 0; i < fileList.length; i++) {
imgList.add(fileList[i].getAbsolutePath());
}
MediaLocator ml;
if ((ml = imageToMovie.createMediaLocator(movFile)) == null) {
System.exit(0);
}
imageToMovie.doIt(width, height, (1000/125), imgList, ml);
}
运行时出错：
用法：java JpegImagesToMovie [-w] [-h] [-f] [-o] -i 由于没有提供输入（-i）forder，假设此JAR位于JPEGs文件夹内。 用法：java JpegImagesToMovie [-w] [-h] [-f] [-o] -i 用法：java JpegImagesToMovie [-w] [-h] [-f] [-o] -i 试图从第一张图像猜测电影大小 线程“main”java.lang.NullPointerException中的异常 at maple.JpegImagesToMovie.main（JpegImagesToMovie.java:342）
第342行
width = firstImageInFolder.getWidth();
4 个答案:
答案 0 :(得分：6)
虽然有点晚了（因为这个问题已经回答了），而且因为巧合的是我在过去几天与ImageIO合作过，所以我只想在这里添加我的答案。特别是如何让JpegImagesToMovie使用png文件的第二部分尚未得到解答，它可能会帮助其他人。
双重压缩问题：正如其他人正确识别的那样，您使用ImageIO.write()有效地压缩JPEG图像两次。 ImageIO是一个基于文件类型的实用程序类（在我们的例子中为“jpeg”）选择适当的ImageWriter。然后它构造一个ImageInputStream并将它传递给编写器。最后它调用了write()方法。几乎@meewoK在他的回答中做了什么。但是，每个ImageWriter都可以使用ImageWriteParam实例来配置其详细信息。 ImageIO显然无法知道每个编写者可以接受的参数，也不知道应该如何配置它们，因此使用默认设置。如果您查看来源JPEGImageWriteParam的默认品质因数为0.75，那么您有效地将此因子与原始文件使用的质量相乘。 （如果它再次为0.75，那么您的最终图像质量几乎为0.75 * 0.75 = 0.56，即您丢失了原始图像的一半。底线：使用ImageIO进行快速读取或写入，但如果需要更多控制，建议的方法是手动配置和使用ImageWriter。
如何让JpegImagesToMovie直接使用PNG文件：如果您查看该类的来源，所有工作都在其ImageSourceStream内部类中完成。它的作用是，它将文件中的字节（每个文件是视频帧）直接加载到创建视频的Processor类。方便地，Processor知道如何直接处理JPEG格式（查看流的构造函数format = new VideoFormat(VideoFormat.JPEG, ...)），因此使用原始文件数据提供它可以按预期工作。
要使其与PNG格式一起使用，只需根据您的方法替换文件后缀是不够的。您需要将PNG数据转换为Processor能够理解的格式（即解码）。在下面你可以找到一个快速而肮脏的方法来做到这一点。 免责声明：以下方法使用更多内存，因为它将图像加载到内存中，并进一步操作它以将其转换为byte[]。因此，性能和内存方面最差。但是，如果不考虑内存和速度，它将允许您直接使用PNG文件。
转化步骤：
a） 使用编辑器搜索并将字符串值"jpeg", "jpg"替换为"png"。原作者将这些值硬编码，在您尝试期间，您错过了一些条目。
b）在ImageDataSource的构造函数中，将第一行替换为第二行：
streams[0] = new ImageSourceStream(width, height, frameRate, images); // delete this line
streams[0] = new PngImageSourceStream(width, height, frameRate, images); // add this line
c）在课程结束时添加下面提供的新PngImageSourceStream的实施。
您现在应该拥有原始版本的工作副本，该副本能够直接读取PNG文件并将其转换为MOV视频（注意：由于使用了编解码器，并非所有播放器都可以播放该新视频.QuickTime和Media Player经典对我来说没问题）
更新1： PngImageSourceStream的原始代码假定为32位PNG文件，我忘了提及限制。下面的版本是第二个版本，支持32位或24位（即没有alpha层）图像。
class PngImageSourceStream extends ImageSourceStream {
public PngImageSourceStream(int width, int height, int frameRate,
Vector<String> images) {
super(width, height, frameRate, images);
// configure the new format as RGB format
format = new RGBFormat(new Dimension(width, height),
Format.NOT_SPECIFIED, Format.byteArray, frameRate,
24, // 24 bits per pixel
1, 2, 3); // red, green and blue masks when data are in the form of byte[]
}
public void read(Buffer buf) throws IOException {
// Check if we've finished all the frames.
if (nextImage >= images.size()) {
// We are done. Set EndOfMedia.
System.err.println("Done reading all images.");
buf.setEOM(true);
buf.setOffset(0);
buf.setLength(0);
ended = true;
return;
}
String imageFile = (String) images.elementAt(nextImage);
nextImage++;
System.err.println(" - reading image file: " + imageFile);
// read the PNG image
BufferedImage image = ImageIO.read(new File(imageFile));
boolean hasAlpha = image.getColorModel().hasAlpha();
Dimension size = format.getSize();
// convert 32-bit RGBA to 24-bit RGB
byte[] imageData = convertTo24Bit(hasAlpha, image.getRaster().getPixels(0, 0, size.width, size.height, (int[]) null));
buf.setData(imageData);
System.err.println(" read " + imageData.length + " bytes.");
buf.setOffset(0);
buf.setLength(imageData.length);
buf.setFormat(format);
buf.setFlags(buf.getFlags() | Buffer.FLAG_KEY_FRAME);
}
private void convertIntByteToByte(int[] src, int srcIndex, byte[] out, int outIndex) {
// Note: the int[] returned by bufferedImage.getRaster().getPixels()
// is an int[]
// where each int is the value for one color i.e. the first 4 ints
// contain the RGBA values for the first pixel
int r = src[srcIndex];
int g = src[srcIndex + 1];
int b = src[srcIndex + 2];
out[outIndex] = (byte) (r & 0xFF);
out[outIndex + 1] = (byte) (g & 0xFF);
out[outIndex + 2] = (byte) (b & 0xFF);
}
private byte[] convertTo24Bit(boolean hasAlpha, int[] input) {
int dataLength = input.length;
int newSize = (hasAlpha ? dataLength * 3 / 4 : dataLength);
byte[] convertedData = new byte[newSize];
// for every 4 int values of the original array (RGBA) write 3
// bytes (RGB) to the output array
// if there is no alpha (i.e. RGB image) then just convert int to byte
for (int i = 0, j = 0; i < dataLength; i += 3, j += 3) {
convertIntByteToByte(input, i, convertedData, j);
if (hasAlpha) {
i++; // skip an extra byte if the original image has an
// extra int for transparency
}
}
return convertedData;
}
}
答案 1 :(得分：5)
将JPEG压缩级别 1 设置为更高的质量。这将导致更大的文件大小，但应该解决质量问题。
但仅将它们编码为：
ImageIO.write(img, "jpg", new File("..." + ".jpg"));
- 如this answer中所示 - 截图如下。
编译并运行链接答案中的代码，向上和向下拖动左侧Slider以查看JPEG（底部/第三图像）中压缩级别的结果。底部的文本区域将显示“质量”级别的字节大小。质量与压缩相反，正如您可能从图像中看到的那样，％80质量的JPEG不仅有点'模糊'，而且已经比PNG的字节大得多。
然后仔细查看代码，特别是：
private Image getJpegCompressedImage(BufferedImage image) throws IOException {
float qualityFloat = (float)quality.getValue()/100f;
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
ImageWriter imgWriter = ImageIO.getImageWritersByFormatName( "jpg" ).next();
ImageOutputStream ioStream = ImageIO.createImageOutputStream( outStream );
imgWriter.setOutput( ioStream );
JPEGImageWriteParam jpegParams = new JPEGImageWriteParam( Locale.getDefault() );
jpegParams.setCompressionMode( ImageWriteParam.MODE_EXPLICIT );
jpegParams.setCompressionQuality( qualityFloat ); // Set the compression level
imgWriter.write( null, new IIOImage( image, null, null ), jpegParams );
ioStream.flush();
ioStream.close();
imgWriter.dispose();
jpgSize = outStream.toByteArray().length;
BufferedImage compressedImage = ImageIO.read(new ByteArrayInputStream(outStream.toByteArray()));
return compressedImage;
}
答案 2 :(得分：4)
我通过绕过ImgIO.write()并使用FileOutputStream直接将字节写入文件来对此进行攻击......
由于互联网上有很多提及，称我无法通过此方法控制图像质量，因此我正在补充ImgIO.write。
如果您一直使用imageIO.write方法保存JPEG图像，您可能会注意到某些图像质量下降。这是因为您无法指示imagIO.write方法将某种压缩质量应用于图像。
我的第一个刺：
import java.awt.image.BufferedImage;
public class Quality {
public static void main (String[] args) {
BufferedImage img;
try {
File f = new File("test" + ".jpg");
img = ImageIO.read(f);
writeJpegCompressedImage(img,"NEW" + ".jpg" );
} catch (IOException e) {
e.printStackTrace();
}
}
private static void writeJpegCompressedImage(BufferedImage image, String outFile) throws IOException {
float qualityFloat = 1f;
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
ImageWriter imgWriter = ImageIO.getImageWritersByFormatName( "jpg" ).next();
ImageOutputStream ioStream = ImageIO.createImageOutputStream( outStream );
imgWriter.setOutput( ioStream );
JPEGImageWriteParam jpegParams = new JPEGImageWriteParam( Locale.getDefault() );
jpegParams.setCompressionMode( ImageWriteParam.MODE_EXPLICIT );
jpegParams.setCompressionQuality( qualityFloat );
imgWriter.write( null, new IIOImage( image, null, null ), jpegParams );
ioStream.flush();
ioStream.close();
imgWriter.dispose();
OutputStream outputStream = new FileOutputStream ( outFile);
outStream.writeTo(outputStream);
}
}
答案 3 :(得分：0)
您可以通过查看此链接http://javahive.in/png-to-jpg-converter/
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