This seems materially different than the reverse operation - taking a book and turning it into an audio experience. Doing so may diminish the book's experience

This seems materially different than the reverse operation - taking a book and turning it into an audio experience. Doing so may diminish the book's experience because the AI voice / TTS may not convey the book correctly and could damage the user experience. Captioning seems more like a facilitation of experience, using only the audio to add an additional layer on it. It's like saying the credits for a movie are copywrited and Amazon can't use that content for X-Ray (I'm aware they use IMBD and Amazon owns that). It's certainly a gray area, but I feel the publishers are simply afraid that buying an audio book that is captioned may cannabalize their text-based book business, which seems disingenuous. The accessibility of a book of text is very different than captioned audio. What if people can't hear well, but like the emotive layer added to captions in a reader's voice/pace, etc? I can see uses for this that could be argued however - for instance, using the captions as a reading facilitator. The customer is using it like a book, with audio captions, not an audio book with hearing-impaired captions. Using the transcribed text to translate to a different language may also be infringing on copywrite as to provide an unofficially translated version of the text. Assuming that there was an app on your phone that you could use to point at the Kindle readhing your audio book out loud and transcribing the text clearly isn't copywrite infringement, so the debate seems to be around Amazon providing this as an integrated service. I think all that needs to be done is to allow the publisher to decide if that feature is enabled or not. Customers will obviously buy books that are captioned over ones that aren't, because you're getting more "content," and I can imagine publishers would charge more for this. Which is of course, what it ultimately comes down to - Money. Publishers who didn't provide captions wouldn't get the business of those who want them, and those that don't care will make a decision on availability and price. Seems like Amazon could let their marketplace decide what people want, but they are in a legal position where they may consider it worth fighting. The trouble begins when you start asking the questions, "well, if Amazon wins, would publishers simply stop publishing their books on Amazon?" Then the monopoly question comes up. I can see arguments both ways, and if the licensing terms to Amazon aren't clear, then Amazon should simply make them clearer and allow the marketplace participants fall where they may.