I believe it would not be advertising to display the next episode of a series, or even auto play it. But it would be advertising to display a different series or film.
For a fuzzier one, how about a newspaper providing links to their other stories at the bottom of an article that you have read? Typically I gain nothing by ingesting more of a particular publication's writing, so that could be an ad rather than useful functionality. Perhaps not in a special circumstance such as if I am trying to catch up on news local to that publication.
(I kind of wonder if internet advertising would be a lot less hated if it had developed with a culture of restraint rather than maximum in-your-faceness, although to be fair, I'm not sure how that could ever have happened.)