U.S. government works are
free of copyright (public domain). This includes all videos and films produced by federal employees as part of their official duty. However, limitations may still apply, if copyrighted material appears in a video.
Based on an extensive review of government video libraries, I recommend the following 11 collections. The video libraries are broken into four categories followed by six tips to improve government videos:
Search the Best Copyright-Free Photos:
Top News Video Libraries

Very up-to-date military news in a television newscast format streamed online by the Department of Defense. The site includes several "channels" for top news, interviews, front line stories, and more. The production quality, timeliness, and anchorwoman are professional grade. On the downside: some videos do not have dates, and the "play" and "playlist" buttons are visually associated with the wrong videos.
Production Quality:
Excellent!
Update Frequency:
Several videos added daily
Accessible?:
No—neither captioning nor transcripts...