can apple tv support high bitrate audio over HDMI?
can apple TV support any audio bitrate higher than 48 k?
Apple TV HD, tvOS 11
48k
48 kHz is a sampling rate, not a bitrate.
Apple TV currently doesn’t support Hi-Res Lossless (sampling rates greater than 48 kHz). But it is a limitation in software.
Apple TV HD, tvOS 11
If and when Apple decides to change Hi-Res audio specifications, it is expected to transition with the latest software update, and for the 4K models.