How can I tell if a TV show I purchase from Apple is SD or HD Pre-Purchase?

When browsing TV shows on AppleTV app sometimes they will show “HD” if it is going to be streamed HD, but if I’m looking to buy the episode from Apple, there appears to be no way to tell if what I’m buying is HD or SD pre-purchase or am I missing something? For example, below AppleTV shows that I can watch Season 4, Episode 1 of Coupling over Prime Video in HD, but if I buy Season 4 from Apple it appears to be the SD version.