What each one is for

A trailer exists to be posted. It lives on a storefront page, a social feed or an advertisement, and it is judged on whether it makes someone stop scrolling.

A film book exists to be finished. It is judged the way a film is judged: whether a viewer stays to the end, and whether the story lands.

Length, plainly

A trailer runs seconds to two minutes at most. Longer trailers do not perform better; they simply cost more.

A film book runs about one minute per thousand words. A 90,000-word novel is therefore roughly a 90-minute film. That single figure is enough to plan a runway and a budget.

What each one costs

A film book here is 12% of the manuscript word count, and the matching audio book edition rides with it. A 90,000-word novel is $10,800 for base production.

A trailer is a far smaller piece of work, and you can cut the plan for one yourself, free, at the Trailer Cutter. A 50% deposit begins a commissioned build; the balance falls due on delivery.

Which one an author actually needs

If the book is already selling and you want more strangers to find it, cut a trailer. If readers finish the book and ask for more of the world, a film book gives them somewhere to go and gives you a second edition to sell rather than a second advertisement to pay for.

Most authors who commission a film book still want a trailer afterwards, because the film gives them footage the trailer can be cut from. Doing it in that order costs less than doing it twice.

Asked and answered

Is a film book the same as an audiobook with pictures?

No. The picture is composed to the read, with cast, score and cutting decisions of its own. An audiobook with a static image on top is a video file, not a film.

Can a trailer be cut from a film book?

Yes, and that is the cheaper order of work. A finished film book already contains the footage, the read and the score a trailer needs.

Do I need a trailer if I have a film book?

They do different jobs. The film book is the work; the trailer is the advertisement for it.