and data 2 being input data indicative of y channels of audio data to be encoded in accordance with a second encoding protocol and the single unified bitstream asserted by encoder 10 to decoder 12 or 14 being determined by output data generated in accordance with an embodiment of the invention in response to the input data for another example the encoder described with reference to fig5 could be implemented in a general purpose processor with the pcm samples asserted to the input of block 20 being input data indicative of six channels of audio data and the unified bitstream asserted at the output of packing and formatting block 30 being determined by output data generated in accordance with an embodiment of the invention in response to the input data in some embodiments the invention is a decoder e g any of those shown in fig9 as receiving the unified bitstream generated by encoder 200 or decoder 91 of fig4 a configured to decode a unified bitstream generated by an encoder wherein the unified bitstream includes at least two substreams the substreams including a first independent substream of data encoded in accordance with a first encoding protocol and a second substream of data encoded in accordance with a.