It's obvious from context that it's the content of the media. To me at least.
If I play you a song on Spotify and say, "Is this a saxophone?", you wouldn't say, "No, it's a iPhone running Spotify."
If a policeman holds up a photograph of a person and says, "Is this the person who attacked you?", the victim doesn't say, "No, it's an 8 by 10 glossy print."
