If you are trying to apply this effect or manipulate the file, here are the most effective tools: 1. Command Line (FFmpeg)
Because it is an .m4v file, you might encounter specific playback issues: Download File Fade to Black.m4v
Professional-grade software allows you to drag and drop this file onto your timeline: If you are trying to apply this effect
For quick, automated transitions without a full editor, use FFmpeg : automated transitions without a full editor
: Seamlessly shifts a video from full visibility to a total black screen.