While forming a studio with Rapport Group and Ashish Parashar, we came across the pitching rights agreement this is signed by the author when he gives the producer the right to pitch his work to the platforms to be made into digital content. In this case, in a studio kind of format, you can look at bundles where you can sell two or three books as bundles to be made into a digital film. Again there are a few things to note the time period of the agreement, the books you are selling to them.
Again an exclusive and nonexclusive deal can be done, or if you have a membership account am amazon prime video direct you can ask the studio to give you the HD footage to monetize when the project is over and launched. Here you can reduce the price per book but get free footage to sell on your private channel.
Otherwise do an exclusive deal and give them the bundle at an incremental price as it increases. The pitching right states the price per book and the ownership of the digital files that are made from the authored book.
Authors need to understand this and study each clause carefully, deliberate with a lawyer, and then make a decision, they can change or add clauses as they choose, amicably of course.