Better input format change for non adaptive codecs

    better handling of input format change for non-adaptive codecs
    
    * this fixes a bug when switching from HE-AAC 22050Hz to AAC 44100Hz (the AudioTrack was not reset and we were trying to send a bad number of bytes, triggering a "AudioTrack.write() called with invalid size" error)
    * this also improves quality switches, making it almost seamless