What is the difference between AVAudioSessionPortBluetoothHFP, A2DP and LE?

Question

Apple AVAudioSessionPortDescription describes three different types of Bluetooth-connected audio ports. But Apple does not explain many of these three types. Can someone help explain more?

Answer 1

AVAudioSessionPortBluetoothHFP | entrance and exit

This is used when connecting to Bluetooth devices via the Hands-Free profile, for example, on cars or headphones. You can access it by setting the audio connection category to AVAudioSessionCategoryPlayAndRecord and the category AVAudioSessionCategoryOptionAllowbluetooth .

AVAudioSessionPortBluetoothA2DP | Only exit

It is mainly used for streaming audio using A2DP (Advanced Sound Distribution Profile). Small portable bluetooth speakers (like Jambox) use this profile to stream audio. You can access it by setting the audio connection category to AVAudioSessionCategoryPlayback .

AVAudioSessionPortBluetoothLE | Only exit

New as of iOS 7, however, I don’t know about any devices that you can transmit audio to implement the Bluetooth Low Energy protocol.