controlling JPEG compression

Programming Questions

inatsu

in Programming Questions • 3 years ago

Hi,

I'm using the Save ("xyz.jpg") function to save webcam captures as an updating image every few frames. I would like to know if there's some way I could control the JPEG compression in this function so that I can save files at higher compression then what I'm getting right now.

Also if you have any other alternatives to save the image on disk with every frame, please let me know.

Thanks.

Replies(4)

antiplast..

controlling JPEG compression

3 years ago

As far as I know, there is no easy way.

There is a hack on this other site, but you'll need to write your own code :
http://www.universalwebservices.net/web-programming-resources/java/adjust-jpeg-image-compression-quality-when-saving-images-in-java

inatsu

Re: controlling JPEG compression

3 years ago

Okay, thanks for pointing to that link, I'll give it a try. Though i really suck at pure Java coding.

inatsu

Re: controlling JPEG compression

3 years ago

Anyway, i found the answer in the old forum here: http://processing.org/discourse/yabb2/YaBB.pl?board=Programs;action=display;num=1120174647

I'm glad those pages are still there. This code seems to work fine for me in Processing.

import com.sun.image.codec.jpeg.*;
public void save(String filename) {
java.awt.image.BufferedImage img=new java.awt.image.BufferedImage(width, height,
java.awt.image.BufferedImage.TYPE_INT_RGB);
loadPixels();
img.setRGB(0, 0, width, height, g.pixels, 0, width);
String extn=filename.substring(filename.lastIndexOf('.')+1).toLowerCase();
if (extn.equals("jpg")) {
try{
ByteArrayOutputStream out = new ByteArrayOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
JPEGEncodeParam p = encoder.getDefaultJPEGEncodeParam(img);
// set JPEG quality to 50% with baseline optimization
p.setQuality(0.05,true);
encoder.setJPEGEncodeParam(p);
encoder.encode(img);
File file = new File(savePath(filename));
FileOutputStream fo = new FileOutputStream(file);
out.writeTo(fo);
println("saved "+filename);
}
catch(FileNotFoundException e){
System.out.println(e);
}
catch(IOException ioe){
System.out.println(ioe);
}
} else if (extn.equals("png")) { // add here as needed
try {
javax.imageio.ImageIO.write(img, extn, new File(savePath(filename)));
println("saved "+filename);
}
catch(Exception e) {
System.err.println("error while saving as "+extn);
e.printStackTrace();
}
} else {
super.save(filename);
}
}

antiplast..

Re: Re: controlling JPEG compression

3 years ago

Great!

I found another snippet on the wiki :
http://wiki.processing.org/w/Save_as_JPEG

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