There are specs for in-stream video advertising [0], as in, the provider injects a 'commercial break' into whatever you're streaming. These cannot be ad-blocked.
They can still be mitigated. At the very least you can blank the video/audio while the ads are on. Personally I'd just get the pirated version, which has the ads cut out for me. If you already paid for the service I don't see anything morally wrong with that.
