A container that holds all the technical details about the video, including track lengths and codec information.
The first box, identifying the file as an MP4 and listing compatible versions.
An MP4 file like "nynaF.mp4" is built on the ISO Base Media File Format, which uses a hierarchical system of "boxes" (or atoms):
Metadata often explicitly names the software used to export the video (e.g., Adobe Premiere, Handbrake).