EPS file incorrectly recognized as AI

[ajaymohite]

Hello Mr. Pontello,

We are analyzing TRID to use as file type indentifier. We created one EPS file in Adobe Illustrator. But TRID is recognizing that file as AI instead of EPS. Can you please Suggest? I already sent you some test EPS files to help you analyze the problem?

Please suggest.

[Mark0]

Hi!

I checked the files you sent me. This is a sample output from TrID:

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59.0% (.AI) Adobe Illustrator graphics (97501/2/16)
 39.6% (.EPS) Encapsulated PostScript (65501/2/14)
  1.2% (.PS) Postscript document (2000/1)
The file formats structure is very similar, neary identical. .AI files are in fact a form of EPS (in my understanding).
Considering that theese are indeed .EPS files created by Illustrator, I don't think the results are too far off / bad.

There's the possibility that TrID's definition for .AI files (ai.trid.xml) may contains some tokens or patterns that's not really specific of that fileformat, but only of the files that I have the chance to analyze (over 60 anyway, so that's not a small number). This obviously would cause the score to be a little higher than the optimal.
If you have a large set of .AI files, you may try to refine the .AI def and see if you can get a more specific one.

But, I repeat, I don't see the present results really as wrong.

Thanks for your feedback,
Bye!

[ajaymohite]

Hello Mr. Pontello,

       We appreciate your ton and detailed reply. But let me tell you some facts. We tested our users (client's) sample EPS files. Most of them are correctly identified as EPS but very few are not. We are using ImageMagic software in one of our projects which does not support AI files at all. So it is very very important for us to know the exact mime type of the file. And even if some EPS files recognized as AI , we should have detailed information to explain the things to our client. 
        Sample EPS files[ user created files in our system] which we sent you yesterday were recognized as AI by TRID. We re-opened some of them in Adobe Illustrator and again re-saved them as EPS. and after that those files are correctly identified as EPS. So what our perception here is, We want to have clean understanding or technical backup/knowledge regarding TRID and its file type identification process, so that we can say anytime to user that contents[files] are are not in correct format.

[Mark0]

I see. I think that for that kind of 100% id capabilities that you need, a much specialized tool would be needed, if ever.
TrID doesn't have specific / hard coded rules, and it rely on the lists of patterns & tokens on the *.trid.xm ldefinitions files for his analysis. If you have a large set of some specific filetypes (.AI & .EPS/.EPSF files in this case), you can try to build some newer / better defs with TrIDScan and see if there's some improvements for your particular application.

As for general purpose usage, instead, I think that the present TrID's shown above are already pretty good.

Bye!