Internally, the BBC have a private streaming platform, [that used to be] called 'Redux' where 90%+ of their entire back catalogue is available for staff and journos to watch and search, as it's all fully indexed with thumbnails, and complete scripts. The UI is something out of the 90s but it works and is used all the time.
Redux is very good at it's job, but it's very much not built as a public streaming platform and doesn't do a lot of real world things you'd need such a platform to do.
