LDAC is Sony's wireless audio codec that transmits up to 990 kbps over Bluetooth, three times the standard SBC rate, enabling near-Hi-Res audio quality on supported devices.
LDAC supports three modes: 330, 660, and 990 kbps. The 990 kbps mode delivers 96 kHz/24-bit Hi-Res audio quality wirelessly. Most Android 8.0+ phones support LDAC; iPhones do not.
Qualcomm's aptX Lossless (1.2 Mbps over Snapdragon Sound) and Sony's LDAC offer the highest current Bluetooth audio quality. Both require codec support on both transmitter and receiver.
LDAC is included royalty-free since Android 8 — most Sony, OnePlus, Sennheiser, Bose, and B&O headphones support it on Android.