You might not be getting the full experience out of Amazon Prime Video on the Apple TV.
December 20, 2017: 5.1 surround sound "coming soon" to Prime Video for Apple TV
In a support document, Amazon now claims that 5.1 surround sound for the Prime Video app on Apple TV is "coming soon". The company currently offers no timeline on when such support will arrive.
Amazon Prime Video may have finally landed on the Apple TV, but if you downloaded the app, you might not be getting the full experience. While the app does indeed stream 4K high dynamic range (HDR) video, the audio might not be quite up to snuff. While several videos are marked as supporting 5.1 surround sound, it seems that no video from the app is outputting in 5.1 channels. Instead, the videos seem to be using 2.1 stereo sound.
Tests conducted by AppleInsider corroborate separate reports indicating that audio on the new Amazon Prime Video app is limited to 2.1 —the first digit for a pair of speakers, and the second for a subwoofer. That's well below the basic 5.1 standard —five speakers, one subwoofer — for modern high-definition content.
Meanwhile, Apple TV owners over on Reddit are having the same issues, with some noting that this problem does not seem to affect the Prime Video app on other devices like game consoles. Meanwhile, the Amazon Help Twitter account claims that the Apple TV app should be supporting Dolby 5.1:
The account also says that Amazon is looking into the issue. Hopefully, any errors will be corrected soon and Prime members and Amazon Video subscribers will be able to take advantage of all the service has to offer on the Apple TV.