Open source JPEG compressors

[inikep]

The first open source JPEG (re)compressor is PAQ (http://mattmahoney.net/dc/), but it's a little bit slow. Here is my JPEG (re)compressor which is based on uncmpJPG from JPEG Open Source Developers Package by Matthias Stirner. It's not optimized for speed and designed for files bigger than 100 kb.
Usage:
a) compression "rejpeg file1.jpg file2.jpg ..."
b) decompression "rejpeg file1.rjg file2.rjg ..."

[Shelwien]

rejpeg surprisingly supports progressive jpegs, which is really nice
(paq and some others don't afaik)

Now, this is the mentioned "JPEG Open Source Developers Package by Matthias Stirner":
http://www.elektronik.htw-aalen.de/p...ge%20v1.0d.zip

Also some other decoders:
http://nishi.dreamhosters.com/u/decoders_0.rar

And this is my refactored version of jpeg decoder from jpeglib v7:
http://nishi.dreamhosters.com/u/djpeg_vA.rar
(supports arithmetic jpegs)

Now here's pjpg source:
http://nishi.dreamhosters.com/u/pjpg_v0.rar
Although its buggy, doesn't support progressive mode, and has worse ratio than rejpeg.
But at least its faster :)

[schnaader]

Good work. Quick test:

Original: 15 files, 10.064.531 bytes
pjpg_v0: 8.381.297 bytes, 34 s
packjpg 2.4: 7.939.727 bytes, 63 s
rejpeg 0.1: 7.987.513 bytes, 74 s

By the way, you might have a look at the attached (corrupt) JPG file. It leads to a crash both in PackJPG and rejpeg.

[m^2]

Sizes:

	File1	File2	File3	File4	File5	File6	File7	Average savings(%)
Original	7419183	1619579	613621	545276	2232323	1690887	100120	0
rejpeg	6365352	1411105	543139	495169	2017362	1232086	85834	14,11
PackJPG	6322183	1393636	533797	492375	2022679	1247830	81499	15,09
pjpg	7405639	1613083	612039	544180	2099753	1678005	99501	1,19

Times

	File1	File2	File3	File4	File5	File6	File7
Original	7419183	1619579	613621	545276	2232323	1690887	100120
rejpeg	12.250	3.078	1.156	0.875	3.000	4.312	0.281
PackJPG	16.625	3.671	1.390	1.109	4.203	4.453	0.250
pjpg	3.953	1.015	0.343	0.312	3.031	1.031	0.125

PAQ8 hung at 99.98% of file1 and 99.90% on file2 with 0% CPU usage, I killed it after some time and didn't try further.
PackJPG 2.4
rejpg 0.1
pjpg_v0
PAQ8px_v69

[Shelwien]

These are probably "progressive" jpegs (except for File5). pjpg and paq8 can't parse these.
You can generate some more files like that with arithmetic coding or new jpeglib8 features -
then even rejpeg/packjpg would fail.

[m^2]

Possibly. But I wanted to have something representative for my workload and that's it.
How can I check if they are progressive?

EDIT: Imagine can show such info, yes except for 5 they are progressive.

[Intrinsic]

This will show you all the internal info of JPEGs and if there are any errors.

http://www.impulseadventure.com/photo/jpeg-snoop.html

[Vacon]

Hello everyone,

not bad for a 0.1!
But to be honest, I was not prepared to find rejpeg saying:

--> reJPEG v0.1 (1/06/2010) - JPEG file compressor by Przemyslaw Skibinski (base
d on work of Matthias Stirner) <--

rejpeg file.jpg -> Expanding... -> 76,5 %

respective viceversa:

--> reJPEG v0.1 (1/06/2010) - JPEG file compressor by Przemyslaw Skibinski (base
d on work of Matthias Stirner) <--


rejpeg file.rjg" -> Compressing -> 79.84%
[...]

Best regards!

[packDEV]

Late reply :-). I already fixed the bug in the latest non public packJPG version and I'll fix it in my Open Source Developers Package, too, within the next few days.