If they needed permissions for conversion, they'd have made a specific mention of that and thereafter confirmed legal ownership.
Officially it means they can legally do wat you want them to do (present the content to users, perhaps transforming it in various ways for some or all viewers), but of course it covers them being able to do far more than that.
You do not need all that.
If my company presented such user agreement I would be quickly reported by users to local Office of Competition and Consumer Protection, audited, fined, and ordered to change that.
I think this would be even challenged at the level of "Abusive clauses registry" that office maintains, so the agreement would be quickly overruled in court.
If no specific clause would be challenged, this is an example of "grossly violates the consumer's interests" rule.
How is big tech allowed to push this shit anywhere? How is this legal in civilized world?
Perpetual is way harder to justify though.
Irrevocable and right-to-sublicense are the red flags for me. Nothing a company sells to us is irrevocable, but everything they take from us is expected to be.