What is the output audio format on the USB C?

Hey Community,

Here is the use case scenario:

• iPhone 15 pro runs Apple Music
• audio format is ALAC at 24b/96kHz
• audio is transferred to an external sound interface through USB-C

Question: What is the output audio format on the USB-C?

thanks

Neset

---------------------------------------------------------

PS:

• Sound interface here is simply a DAC which is connected to an HiFi system.
• In a support conversation, an Apple employee said that the output format is ALAC. However, I realized later that there is no ALAC decoder in the sound interface (Steinberg UR44C). And, I have a good sounding music. Therefore, I started to think that iPhone outputs PCM which is the subject of this question.
• Below is the overall block diagram