The present invention relates to a method and apparatus for processing a signal. An object of the present invention devised to solve the problem lies on a method and apparatus for processing a signal, which allows a signal having optimized signal transmission efficiency to be transmitted/received. According to an aspect of the present invention, there is provided a method of processing a signal including receiving a broadcasting signal including audio data coded using a pilot reference value and a pilot difference value, demodulating the broadcasting signal in consideration of a scattered pilot which varies over time and a continual pilot which is fixed over time in a frame of the received broadcasting signal and decoding the demodulated signal to obtain a broadcasting transmission stream, demultiplexing the broadcasting transmission stream to obtain coded audio data in an Internet protocol (IP) packet and an identifier for identifying a method of decoding the audio data, obtaining the pilot reference value corresponding to a plurality of data and the pilot difference value corresponding to the pilot reference value from the coded audio data and obtaining the audio data using the pilot reference value and the pilot difference value.