Depending on a video or audio container it can store various metadata or information like title, description, year, author, episode, album, track etc.

Using FFmpeg to add this metadata to a media file is a simple task. The parameter is

-metadata X=

With X being the type of metadata being added, you can find this information in the tables below. If I wanted to add a title to my video here is the command:

ffmpeg -i input.mp4 -metadata title="The video titile" -c copy output.mp4

This will produce:

As i used copy no encoding was done and this process happened instantly.

Here are the metadata keys:

MP4, MOV, and Quicktime

MP3