Coded Audio Signal Generation. It is hard to imagine the current audio world without keywords such as surround sound, 5.1 channels, etc. Originally designed for use in movie theaters, these multichannel transmission methods have in the meantime found their way into private households. In all multichannel methods, the six channels generally used are data-reduced for transfer in the digital audio formats established for stereo transmission. In the home units, such as audio/video receivers, the data streams are decoded for analog and multichannel replay.