Based on current search trends and public records, "731mp4" appears most frequently as a timestamped filename for various organizations:

: Utilized by government entities, such as the City of Des Moines , for skycam timelapses or community service announcements.

: Creating a "Year in Review" or "Day in the Life" segment centered on July 31st.

: Found in social media archives for teams like the Reno Aces to identify game highlights or player introductions from that specific date.

Are you trying to from a certain year, or are you designing a content calendar using this naming format?