A brief is a short document written before a shoot that states what the video is for, who it is for, and what it needs to say — so a filmed idea and the plan behind it stay the same thing, whether one person is shooting it or a whole team is.
A shot list is the brief translated into camera instructions; the brief itself is the layer above that, the part a client or a manager reads before anything is filmed.
A brief written down, even a short one, is what lets a scenario be handed to a videographer or a teammate without every decision being re-explained out loud.
A short brief is usually enough: the point is not documentation for its own sake, but making sure the person deciding what the video says and the person filming it agree on that before the camera is on.
A brief written after the fact, once footage already exists, does less work than one written before it — it becomes a caption for footage rather than a plan the footage was shot to fulfil, and the two produce different videos even from the same idea.
A common way a brief fails is padding it with everything that might be useful instead of the handful of decisions that actually change what gets filmed: who the video is for, the one thing it needs to say, and the call to action at the end. A page of context nobody reads before the shoot is not a brief; it is documentation that arrived too late to change anything.
Where it comes from
HubSpot's own guide defines a creative brief the same way.
A creative brief is a short document that sums up marketing, advertising, or design project mission, goals, challenges, demographics, messaging, and other key details.
Read the source: HubSpot — How to Write a Creative Brief.
What Rankfield reads
The landing page answers this directly, in its own words:
Your account end to end, your competitors, and the wider market around you: posts, videos, captions, comments, rhythm, what you offer. It watches the videos, not just the numbers under them.