28. The apparatus as in claim 25 wherein the first audio data is stored within the first audio file in a plurality of fixed-size access units and wherein generating the universal representation comprises packing the fixed-size access units into a plurality of audio data structures, the audio data structures of the universal representation being larger than or equal to the fixed-size access units of the first audio file.
29. The apparatus as in claim 28 wherein the fixed-size access units of the universal representation are an integer multiple of the fixed-size access units of the first audio file.