Entity size
Average entity size - base for bitrate and capacity calculation. Sum all fields/columns average size.
Warning
Be careful with cases, when your service integrates into existed system.
For example, video into airbnb room page (`video` entity inside `room` entity)
Do not go straight to estimation. Describe system boundaries.
Your questions:- Which part of all pages is expected to be with video's?
- Which services I need to extend to add my entity to search, show and edit?
- Can I add columns/fields to existed database?