Any Java libraries like packjpg?

Newbie & Debugging Questions
#1

Is there any Java libraries like packjpg? http://www.elektronik.htw-aalen.de/packjpg/index.htm
Basically its for highly compressing(23%) jpeg in lossless form.

#2

After the search I couldn’t find anything that really would help me.

Nothing of the top charts are in Java: http://www.maximumcompression.com/data/jpg.php

But an application called Image Optimizer Pro helped optimises jpegs quite small enough with little quality loss but using something like packjpg would of gotten them a lot smaller.

Also there is a program called jpeg reducer helped optimise jpegs (lossless), which is already built in Image Optimizer Pro. I used it on my photo collection to get 10%+ reduction.

#3

It is possible to have loss-less JPG in Java as well, if you disable the chroma subsampling and set quality to 100%, you should get a lossless compressed image.

#4

[quote]It is possible to have loss-less JPG in Java as well, if you disable the chroma subsampling and set quality to 100%, you should get a lossless compressed image.
[/quote]
I’m talking about lossless jpeg compression not lossless jpegs.

#5

Does it have to be lossless jpg? Regular png encoding is lossless and should be better than lossless jpeg.

Alternatively some googling suggests that the java-advanced-imaging API supports it, but I hear that JAI is a bit of a pain when it comes to distribution.

#6

[quote]Does it have to be lossless jpg? Regular png encoding is lossless and should be better than lossless jpeg.
[/quote]
I was looking for more ways to compress a jpeg in a zip like container without loosing quality, only a number of special formats can compress jpeg even more which none are supported by Java.

I also looked at WebP, Googles new web image format, but there is no support really for it atm(and no Java version).

#7

[…] would of gotten […]

Dude. Seriously.

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I recommend to use jpegtran.

jpegtran -copy none -optimize -outfile out.jpg in.jpg

This discards all meta/exif data and it also tries to optimize the huffman tables (this is lossless).

In extreme cases that optimize step can save as much as 50%, but it can also make the file slightly bigger. E.g. if you save for web with Photoshop, the JPGs will be already pretty much optimal. So, check the file size.