Here's an excerpt from the project home page that describes JHOVE:
JHOVE provides functions to perform format-specific identification, validation, and characterization of digital objects.
- Format identification is the process of determining the format to which a digital object conforms; in other words, it answers the question: "I have a digital object; what format is it?"
- Format validation is the process of determining the level of compliance of a digital object to the specification for its purported format, e.g.: "I have an object purportedly of format F; is it? . . . ."
- Format characterization is the process of determining the format-specific significant properties of an object of a given format, e.g.: "I have an object of format F; what are its salient properties?"