Now I want to submit one app about video with playing, so need documentation demonstrating my right to use the third-party content. If my app is just showing and not playing, even without playing entrance, Do I need to provide the documentation demonstrating my right to use the third-party content?
Expect your answer, thanks!
App Review isn't here, and they're the only ones that can answer your question when they have a chance to see your app.
If I were you, I'd have that proof ready, in any case.
The question is whether you are violating the copyright rights of the owner of this work. Copyright includes the right to publicly display the work and also to distribute the work. Perhaps (although I think not) you are not 'displaying' the work if all you are doing is "showing and not playing". However, you are clearly distributing the work and therefore subject to the copyright rights of the owner. Whether or not Apple will require the documentation depends on what App Review decides to do when they review the app. No one can guess the answer to that.
