The Xiaomi 15 supports Aptx lossless, which is a Bluetooth audio codec developed by Qualcomm designed to deliver lossless, CD-quality audio (16-bit/44.1kHz) over Bluetooth.
For your reference, here are the advantages of Aptx lossless on the Xiaomi 15:
1. AptX lossless solves the problem of limited bandwidth of Bluetooth by dynamically adjusting bitrate to optimize for connection quality, supporting up to 1Mbps bitrate for lossless transmission, and falling back to aptX Adaptive when the wireless environment is congested;
2. It is designed to be efficient and balancing lossless audio with good battery life for both the source device and headphones;
3. You don’t have to manually switch codecs or settings. The system detects when lossless is possible and activates it automatically.