[JTM]

This is basically a recruitment video from the Japanese National Defense Department. The YouTube caption mentions the title:

Mamoritai Hito Ga Iru - Rikijou Jieitaikan Kara No Tegami
(We are protecting you - Open Letter from the Japanese National Self Defense Department)

It further mentions that this was produced in 2009 by the Public Relations branch of the Japanese National Self Defense Department and is currently being played in 3-D theaters owned by the SDF. The film follows a young recruits experience undergoing basic training and shows various military exercises that the SDF conduct.

Nothing ominous or strange about it but you are right it one long 30+minute recruitment video (broken up into two parts). This YouTube channel belongs to the JGSDF (Japanese Government Self Defense Force) and they have a lot of other shorter clips which follow a similar documentary style look and feel.