Comment by Tempest1981

Yes, VLC works fine for playing. The user wanted to edit some mp4 videos with iMovie (vs ffmpeg).

I think it was an M4 Mac. Does iMovie need a codec pack? I know some PC OEMs don't ship an h.265 codec, pointing users to a $0.99 download. Thought Mac would include it, being aimed at content creators. Hoping for a cheaper solution than Adobe Premiere.