HiRes Lossless Audio via lightning port

Hi community members,

Currently, I have a Yamaha AV receiver (RX-V677) which is an Apple MFi certified device as it has the “Made for iPod/iPad/iPhone” certification symbol.

I am able to connect my iPad Air (running iOS 17.0.2) to the RX-V677 via the supplied lightning to USB-A cable. The RX-V677 is then able to access and play music from my playlist and albums in Apple Music. I can also control playback functions like stop/pause/skip/next or previous track using the RX-V677 remote.

The quality of the audio is fantastic but I am not sure if the audio being sent through to the RX-V677 receiver is lossless or HiRes lossless. When I check the input format of the audio being set through the USB, the RX-V677 says it is “Digital” and 2 channel and nothing more.

When I play a HiRes lossless music in the Apple Music app, I do see the Lossless or HiRes Lossless indicator. So I know that the iPad has downloaded or is streaming the HiRes lossless audio.

I am also aware that the RX-V677 supports FLAC/WAV up to 24bits/192khz and ALAC up to 24bits/92khz.

As some of the music I play are in HiRes lossless 24bits/192khz, the RX-V677 still happily plays the audio although 92khz is the limit.

So my thinking is that the interface that connects the iPad to the RX-V677 is using PCM/WAV streaming audio packets rather than sending the ALAC file contents through to be played. Or that the interface downgrades the HiRes lossless audio stream to something like 24bits/48khz.

Can anyone confirm what audio format is being streamed or sent using this type of connection?

thank you for your time,

Norman.