Systems, methods and software for sample rate conversion with unknown input and output clocks are disclosed. In one embodiment, a method for an asynchronous transfer of audio data includes: receiving the audio data by an antenna of a receiver (RX); storing the audio data in an input buffer of the RX; and receiving data words from the input buffer by a sample rate converter (SRC). The consecutive data words are received from the input buffer at an adjustable period T. The method further includes tracking a filling level of the input buffer; and based on the filling level of the input buffer, adjusting the adjustable period T. When the filling level of the input buffer is below the target level of the input buffer, the adjustable period T is increased. When the filling level of the input buffer is above the target level of the input buffer, the adjustable period T is decreased.