[cricalix]

The dynamic ad insertion comes from the service backing the URL for the podcast in the RSS feed. If all you receive is a stream of bits which decode to audio, how do you tell that it’s an ad that’s been spliced into the audio?

If Spotify are actually hosting the content themselves, it’s a different story, and I’d expect them to be able to not insert ads for premium users. If they’re just reading the feed and sending the request to origin, it’s a bit more difficult.