Decode encoded audio buffer to PCM format

Question

I'm new to iOS and Swift.

I would like to decode some encoded audio data (MP3, AAC...) to obtain an AVAudioPCMBuffer.

I wanted to do so through the AVAudioBuffer parent class, but it seems to be an abstraction layer to serve only the AVAudioPCMBuffer class.

The final result should be similar to the Web Audio API's decodeAudioData function

Is there a class/method to do so directly? Otherwise, what is the easiest way?

Thanks!