Some methods may involve receiving a block of audio data, the block including N pulse code modulated (PCM) audio channels, including audio samples for each of the N channels, receiving metadata associated with the block of audio data and receiving a first set of values corresponding to reference audio samples. A second set of values, corresponding to audio samples from the block of audio data, may be determined. The first and second set of values may be compared. Based on the comparison, it may be determined whether the block of audio data is synchronized with the metadata.