HD Audio: Improved performance and support for HD audio delivering clearer, sharper, and richer quality sound. HDR improves the brightness and color range of video to improve the picture quality and experience.
HDR: Android 9 adds built-in support for High Dynamic Range (HDR) VP9 Profile 2, so you can watch HDR-enabled movies on YouTube and Google Play Movies. No more blasting music too loudly when you reconnect to your car or headphones.
Volume memory per Bluetooth device: Android 9 will now remember the last volume you set for each of your Bluetooth devices. Sound delay reporting: Android 9 offers support for headsets with sound delay reporting, so video on your device and audio on your headphones can always stay in sync.
Incoming phone calls will be sent to all connected Bluetooth devices that can accept, so you'll never miss a call. Multiple Bluetooth connections: With Android 9, you can connect up to five Bluetooth devices and switch between these devices seamlessly.