Change the default video format in the Apple TV app
If you have a slow internet connection or want to use less data, you can choose to limit all purchases and rentals or playback to the standard-definition (SD) format in the Apple TV app. If you want better quality high-definition (HD) videos, turn these settings off.
Limit purchases and rentals to SD
- Go to the Apple TV app  on your smart TV, streaming device, or gaming console. on your smart TV, streaming device, or gaming console.
- Open the sidebar, then select Settings. 
- Turn on Limit Purchases and Rentals to SD. 
Limit playback to SD
- Go to the Apple TV app  on your smart TV, streaming device, or gaming console. on your smart TV, streaming device, or gaming console.
- Open the sidebar, then select Settings. 
- Turn on Limit Playback to SD.