A recording and reproducing system is broken down into a recording unit for producing a digital audio data signal from MIDI music data words asynchronously produced at irregular intervals and a playback unit for reproducing the MIDI music data codes from the digital audio data signal, wherein synchronous data nibbles are supplemented in the irregular intervals among the MIDI music data words for producing a data stream, and the digital audio data signal is produced from the data stream through a differential phase shift keying and a phase code modulation so as to record the MIDI messages in a digital versatile disk at high dense.