I can’t believe I haven’t heard of this still image format before — it’s called ART and was apparently used in earlier incarnations of America OnLine’s service. All that anyone knows about it is that it is based on compression techniques licensed from an outfit named Johnson-Grace, a firm that AOL later purchased.
The Wikipedia page implies that this format is to still image formats what Bink is to video codecs — if the marketing literature is to be believed, the compressor analyzes the data to be compressed and selects from a number of coding methods based on the assessed characteristics. The Wikipedia page also links to several J-G patents, none of which I have read.
A colleague sent me a bevy of samples for study. Where to start with a reverse engineering effort? There seems to be plenty of ancient programs that can work with the format. However, it seems reasonable that the code for decoding ART files must live on any of the billions of free AOL signup disks known to exist.
atmsunrise.art, BUILDING.ART, and CARBLO3B.ART are JPEG/JFIF
i_mobilecomm_product.art is a GIF
Hmm, good catch…
$ file *
[actual ART files omitted]
BUILDING.ART: JPEG image data, JFIF standard 1.01
CARBLO3B.ART: JPEG image data
atmsunrise.art: JPEG image data, JFIF standard 1.02
i_mobilecomm_product.art: GIF image data, version 89a, 201 x 150
I’ll strike those from the archive.
Hehe, “Johnson-Grace”, so it is indeed not by chance that the files start with “JG”.
I guess having the decoded files as decode bitmap sure would be useful, at least for those like me who prefer to try reverse-engineering by staring hard at hex data and a bit of guessing.
Though that may be the reason why I mostly stick to trivial stuff like game archive formats (http://sourceforge.net/projects/extractor-gtk).
I converted the samples to PNG with the evaluation version of Graphic Workshop Professional (linked on the Wikipedia page):
http://drv.nu/temp/ART/
You’re welcome to upload these with the samples if you’d like…
As a side note, apparently Graphic Workshop uses a few DLLs from Johnson-Grace to decode and encode ART, which were also the subject of a security advisory a few years ago as part of Windows/Internet Explorer: http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=407
will this be the first image format ffmpeg will have support for, that imagemagick does not? :)
Only if you can RE it.
I learned quite a bit about this format back when me and my family first got online since we were using Compuserve and unbeknown to us at that time Compuserve was owned by AOL and used pretty much the same browser software, so when I would save art from the internet it would end up saved as .ART files. It took a while to find out how to turn the setting off in Compuserve because every site that told how to turn off AOL saving images as .ART files neglected to say the same was true for Compuserve, and while trying to figure out what to do I learned the history of this headache of a format. As you said it was developed by a company called Johnson Grace which was gobbled up by AOL who thought this format would help them get an edge because of how small it could shrink a file using fractal wavelet compression, and they convinced Microsoft to hop on board with them by having Internet Explorer be able to read the images, back when IE was trying to be the dominant browser and AOL got them to believe the format would become the next image standard because of the sheer numbers of users AOL had who would be using the format when it was introduced. The problems started almost immediately when people complained about fuzziness in the images, which was because because AOL set the compression levels much too high, favoring size over quality, and so they could make a file be only 10 KB that may have been 130 KB as a JPEG but it would be ruined in the process and not worth saving anyway. It was considered a complete failure after a few years and quietly abandoned in later AOL browsers, others have tried to use a similar technique to compress images but after the huge rejection by users of the .ART format most moved to other methods. Graphic Workshop Professional did have support for .ART file and the unique thing to that is they had a setting to choose how you wanted the program to try and compress the image, which ironically when done with a setting that favored quality it did produce an image that was smaller than a similar quality JPEG but without the fuzziness and image artifacts, so if AOL had been less concerned with super small size over quality the format could have become one of the web standards. The burial of the format finally occurred when an internet security group discovered a way to sneak a virus inside .ART files and Microsoft stripped it for good out of Windows and Internet Explorer. Graphic Workshop Pro has a plugin that has the files that Windows used to use to decode the files that can be downloaded to use with current versions of their program.
I don’t know if that will help any, I kind of hated the format but ended up with too many images saved in it and had to have something to convert from it. If I knew who to ask at AOL or Google, since they own a chunk of AOL shares, I would suggest they release the specifications on the format so that programs like Irfanview and XnView could be able to read it for all those who are stuck with .ART files, but it seems that AOL plans to keep it locked up for spite. The least they could do is make a small converter to help folks.
Konvertor is supposed to read that AOL ART
Here’s some information on the ART dlls that ship with AOL.
JGAOL.DLL : Johnson Grace Drag & Drop & ART Stuff /Loaded by Manager
JGAWAOLS.DLL: Johnson Grace Audio Decoder
JGDWAOL.DLL : Johnson-Grace Interface
JGEWAOL.DLL : Johnson-Grace Encoder
JGFRAOL.DLL : Johnson-Grace Foreign Image Decoder (GIF, JPG, BMP)
JGMDAOL.DLL : Johnson-Grace Midi Decoder
JGPLAOL.DLL : Johnson-Grace main ART play for decoding ART 4.0 and below
JGSDAOL.DLL : Johnson-Grace Speech Decoder
JGSHAOL.DLL : Johnson-Grace Slide Show Decoder
Konvertor failed to display or convert any of my AOL ART images.