JPEG compression

[Karsten Wutzke]

Hi all!

By any chance, is there any way with the JDK to get an estimate of an
image's compression level? I know there's no definition of JPEG
compression, but I am thinking of just an estimate, approx. 10% within
range.

Is there such a critter in the Java world, possibly through a 3rd party
library?

TIA,

Karsten

PS: X-Posting to clj.gui as well, I believe there are many dealing with
images.

 

[Andrew Thompson]

PS: X-Posting to clj.gui as well, I believe there are many dealing with
images.

...and you even set the follow-ups (to c.l.j.p.)!
Very thoughtful of you, thank you.

It might add the 'cream to the cake' if you also mentioned that
straight after the mention of the X-post, so that if anyone
replied from c.l.j.gui, they might understand why their post
did not appear on that group.

[ BTW - Hope you resolve the technical issue. ]

 

[Andrey Kuznetsov]

By any chance, is there any way with the JDK to get an estimate of an

image's compression level? I know there's no definition of JPEG
compression, but I am thinking of just an estimate, approx. 10% within
range.

jpeg roughly includes 3 comression types: 2 of them are lossless ( [huffman
| arithmetic] and RunLength ), and 1 lossy.
compression level depends only on that lossy compression.
For example with Photoshop you can choose between 12 levels
The only difference is the quantisation table.
^^^^^^^^^^^^^
BTW Photoshop 6.0 has a bug regarding this - images compressed with quality
7 are smaller then those with quality 6
Since quantisation table is always included you can easy check image
quality/compression level.
I'll include jpeg-compression-level-check with next version of Imagero
Reader.

Regards

Andrei

 

[Ann]

Hi all!

By any chance, is there any way with the JDK to get an estimate of an
image's compression level? I know there's no definition of JPEG
compression, but I am thinking of just an estimate, approx. 10% within
range.

Is there such a critter in the Java world, possibly through a 3rd party
library?

TIA,

Karsten

PS: X-Posting to clj.gui as well, I believe there are many dealing with
images.

Get the width and height of the image, then the compression is

<size of file compressed> / <width * height * 3>

 

[Stanimir Stamenkov]

/Karsten Wutzke/:

By any chance, is there any way with the JDK to get an estimate of an
image's compression level? I know there's no definition of JPEG
compression, but I am thinking of just an estimate, approx. 10% within
range.

Is there such a critter in the Java world, possibly through a 3rd party
library?

Is there such a critter in the non-Java world?