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A JPEG Encoder written in Java™

And it can write to a file, too!

James R. Weeks of BioElectroMech, in desperation for a Java JPEG encoder, has written one.  It is provided here!

DOWNLOAD for $19.95

This encoder is an implementation of the baseline JPEG specification and saves files in the JFIF format.   In order to use it in your Java applications, simply create a JpegEncoder object, specifying an image, the desired quality, and an OutputStream, and then call that object's Compress method:

...

JpegEncoder jpg = new JpegEncoder(image, quality, outStream);

jpg.Compress();

...

The JpegEncoder object has its own MediaTracker, so you can just create an image object and initialize it to get image.  

quality may be any integer from 0 to 100.  0 is maximum compression and 100 is minimum compression.  70 - 80 is an excellent range but 50 gives good results--the image degradation is just noticeable (and for the test image, the resulting jpeg file size was 3% of the original BMP file).

Any OutputStream can be sent to the JpegEncoder object.  JpegEncoder creates a BufferedOutputStream using the outStream object.

Included in this release is Jpeg.java, a command line interface that allows the user to create a JPEG file from any of the image formats that the Java Virtual Machine can read.  Jpeg.java also provides an excellent example of how to use the JpegEncoder in your own applications.

Inspiration for this encoder was provided by Florian Raemy's JPEG encoder--the one that doesn't write a file.   More importantly, a major portion of the code was based on the C code in the Independent JPEG Group's 6a release of their JPEG library.  A few things were done differently to take advantage of Java's capabilities.  The result is a surprisingly fast JPEG encoder and JFIF writer.

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