TrIDNET is a very small program that can identify unknown file formats (with or without an extension in the file name).

It relies on a continuously updated database of definitions (2400+ as of this writing), and allows the user to add and upload their own definitions to the TrIDNET site.

Have you ever had a file that you simply could not identify? Let’s say that the file in question had no extension in its name for you to look it up in Google.

Enter TrIDNET, a program that can scan any such file and present you with a percentages of file format probabilities that total 100%. Usually, in my testing of this tool, the highest percent probability is correct every time (see screenshot).

I tested this program with a number of files where I removed the extension. These included the following formats: XLS, DOC, TXT, CSV, FLV, SWF, WMV, AVI, MPG, PPT, PNG, JPG, MOV, MP3, MP4, RMVB, EXE, VCS, and CBR. Here’s what I discovered:

  • This program does not consider TXT or CSV files to be ’file formats’
  • For each one of these files, TrIDNET’s first guess (i.e. the one with the highest percentage of probability) was the correct one.
  • Most of the multiple probabilities for a single file stem from the fact that the file contains multiple formats; e.g.. a MOV video file contains an audio track that’s a certain format, or a PPT powerpoint file contains an embedded Excel sheet (XLS). TrIDNET will display all of this information in its analysis.
  • TrIDNET will detect executables (EXE).
  • When file formats are merely renamed extensions of another format, the original format will be identified, even when the extension is in the file name. For example, a CBR file (which is really a renamed RAR arhive) was identified as RAR.

One thing that can be improved (which the author has promised in an upcoming version) is the way this program loads definitions. These are downloaded separately, and if they’re not in the default location you will have to point the program to them every time. Although TrIDNET detects and scans all 2400 definitions in a flash, I had to point it to one of the definition files rather than the folder. This scan has to occur every time you use the program and, further, I was surprised that it didn’t simply remember where it found them the last time around. It would be truly a wonderful addition to the program if it automatically scanned for updates on the website and downloaded these automatically whenever they occurred.

All in all this is a very interesting program. Most people will probably not need the service it provides on a continuous basis, but if and when you do need it, this program does a remarkable job. Add to this the fact that it is continuously updated with new format definitions and you realize that the author has created one great tool.

Version tested: 1.8

Compatibility: WinAll. Requires .NET Framework.

Go to the program home page to download the latest version (approx 33K) and and definitions file (approx. 427K).