Vidalin

Vidalin is an M4V (MP4) video tag editor that is very similar to excellent applications already available such as Lostify and MetaX.

Like these other editors, Vidalin utilizes the AtomicParsley command line application as its primary tagging engine, but tries to seek a ‘middle ground’ between Lostify’s simple, effective one-file-at-a-time approach and MetaX’s full-featured powerful multi-file multiple-tag approach.
Moreover, Vidalin now encodes (via embedded Handbrake 0.9.4), performs auto-lookups for tagging information and cover art, then tags your videos in one step.