Abstract: A multiple channel multiplexing apparatus has a data compressor portion for producing compressed data, and a data expander portion for expanding the received compressed data. The data compressor portion has a data compression circuit for data compressing digital audio data and outputting the resulting data blocks, a sub-block divider for dividing the data blocks output from the data compression circuit into sub-blocks, a sub-block ID flag adding circuit for adding a sub-block identification flag identifying the sub-block arrangement, a multiplexer for generating sub-block groups by combining a plural channel group of sub-blocks with the added sub-block identification flags, and multiplexing the sub-block groups to the digital audio interface format.