I think it would be enough if they encrypted the video contents and stored in blocks out of order, ideally I would also have it streamed but let's be realistic

I think it would be enough if they encrypted the video contents and stored in blocks out of order, ideally I would also have it streamed but let's be realistic about bandwidth and availability requirements for that. In the end there will always be significant on device storage. Make sure that the people who are responsible for the decryption and delivery of the content have incitement that the result is useful.