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Knowledge Base

What Is A File Category?

category

The Category is a very broad piece of metadata you can find in a multitude of files. Check out what it means and what differentiates it from File Type and File Type Extension.

The Category is the broad family a file belongs to. It answers the roughest possible question about a file, which is what kind of thing it is: a picture, a sound, a video, a document, a package of other files.

How it differs from file type and extension

A metadata report describes what a file is on three levels of detail, and it helps to keep them apart. The extension is the tail of the file name, such as .jpg. The file type is the exact format, JPEG. The Category is the group that format belongs to, raster image. Many different file types with many different extensions share one category: AI files (extension .ai) and SVG files (extension .svg) both belong to the category of vector image files, even though the two formats have almost nothing else in common.

The value is not typed in by anyone and is not read from the file name. It is worked out by the software inspecting the file, from the structure and the identifying marks inside it. That is also why the category can disagree with the extension. If it does, the file has been renamed or was saved in a different format from the one its name promises.

Common values

Categories are short lowercase labels. Popular examples include:

  • audio
  • application
  • archive
  • executable
  • raster image
  • vector image
  • text
  • video

There are many more. The idea is closely related to the MIME type, the label programs use to describe content they send to each other: in a MIME type such as image/jpeg, the part before the slash is essentially this same category, and the part after it is the specific format.

Why it matters for your file

The Category is the fastest sanity check you can run on a file whose origins you do not know. A download called invoice.jpg that reports a category of executable is not a photograph, and that is worth knowing before you double-click it. More prosaically, it tells you which program to reach for when an unfamiliar extension gives you no clue.

It also explains the shape of the rest of the report. Each category brings its own set of fields: a raster image has a width, a height and a bit depth, an audio file has channels and a bit rate, a text document has a character count. Once you know the category, you know which rows to expect and which ones are missing for a good reason. The field holds no personal information at all.

Meta Keys

Book Name When you check the metadata of an e-book file, you may come across information about the Book Name. Find out what this value is, where it comes from and why it matters. Byte Order The Byte Order is one of the hidden details you find in a file when you check its metadata. Find out what it means and what it tells you about how your file was written. Camera Make Camera Make is the exif information that names the maker of the camera a photo or video was shot with. Find out what this value looks like and what it tells you. Channels Wondering what the number of Audio Channels says about your file? Find out what a channel is and what the count tells you about your music, recording or video file. Character Count With Spaces The Character Count is important information about your document or even e-book file, and you can easily find it out by checking the metadata of a file. But what does Character Count With Spaces mean? Characters Characters is a rather generic piece of metadata. Find out what it means precisely and in which kinds of files you are likely to find this kind of meta information.
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