Funny enough, the Netflix App on iOS/iPadOS now supports spatial audio. I originally wanted to test how good the stereo-to-spatial conversion of iOS 15 works on Netflix content. To my surprise, once I enable spatial audio on my iPad, its not showing that conversion ist enabled, but instead says ‘Netflix – Dolby Atmos’ or ‘Netflix – Multichannel’ based on what content I am watching. Once I turn off spatial audio, however, the text is not reading ‘Spatial Audio off – Atmos available’, but instead gives me a convert stereo to spatial button. Thus, I think this is what happens:
If you are watching Apple TV+ on your iPhone, the device receives an Atmos signal, even if your AirPods are not connected, but the iPhone converts this down to stereo. If your AirPods are connected, it will offer switching to spatial audio. If spatial audio is not enabled, however, you are receiving the downconverted stereo mix.
If you are watching Netflix on your iPhone, the device will receive a stereo signal if spatial audio is not enabled/your AirPods are not connected. If your AirPods are connected and you are not using spatial audio, you will get a stereo source, not an Atmos to stereo conversion like on ATV+. Thus, iOS will only offer upconverting this stereo to spatial, as there is no Atmos audio signal…yet! Because if you opt-in upconverting, the Netflix App recognizes that you are now using spatial audio and thus, it will (which is new) request the multichannel/Atmos stream from the server. Thus, you will not get a stereo-to-atmos upmix, but the actual atmos stream!
However, when watching Netflix on the Apple TV, this update seems to break that stereo-to-atmos switch and thus, there won‘t be a server request from the Netflix app. Before this update, the Apple TV simply took the stream it was going to send towards your AV Receiver/TV and gave it to the AirPods. Now, something seems to be broken.
However, there is a good chance that this feature is going to come back, why else would Netflix finally implement spatial audio support on iOS/iPadOS. Disabling this support on the Apple TV at the same time on purpose would be kinda… counter-intuitive.