Apple today shared a new support document confirming that the HomePod and HomePod mini will gain lossless audio support for Apple Music in a future software update, and the document also reveals some other tidbits.
First, the document indicates that the Apple TV 4K "currently doesn't support Hi-Res Lossless," with only the standard Lossless tier ranging from 16-bit at 44.1 kHz to 24-bit at 48 kHz to be available on the Apple TV 4K at launch. Apple's use of the word "currently" leaves the door open to a future software update with Hi-Res Lossless support for the device, but Apple has not confirmed this at this time.
The Lightning to 3.5 mm Audio Cable was designed to allow AirPods Max to connect to analog sources for listening to movies and music. AirPods Max can be connected to devices playing Lossless and Hi-Res Lossless recordings with exceptional audio quality. However, given the analog to digital conversion in the cable, the playback will not be completely lossless.
Lossless audio refers to a form of compression that preserves all of the original data, which can result in an improved listening experience, although to what extent is debated. Apple's support document acknowledges that the difference between Apple Music's standard audio and lossless audio will be "virtually indistinguishable."