[radlad]

What exactly is ffmpeg's one thing?

Or curl's for that matter?

[whatshisface]

Curl's "one thing" is to get files from the network in every conceivable way possible. Ffmpeg's is to convert media files between every conceivable set of formats possible.

[kblev]

Curl does loads of stuff, supports so many protocols - HTTP, LDAP, FTP etc.

[corobo]

CLI video editing

Make web requests