A high-capacity performance-preserving blind technique for reversible information hiding via MIDI files using delta times

A new high-capacity information hiding method for embedding secret messages into MIDI files is proposed. The method can preserve the original musical performance of the cover MIDI file. The property of the variable-length quantity, which expresses the magnitude of the delta time before every event in a MIDI file, is utilized for secret bit embedding. The embedding is accomplished by padding the delta times with different numbers of leading constant bytes of 8016 to represent the secret bits. The method is both reversible and blind because the original cover MIDI file can be restored completely from the stego-MIDI file by extracting the embedded data out from the resulting stego-MIDI file without referencing the original cover MIDI file. A capability of hiding a large amount of secret information is achieved since the delta time is a basic parameter that appears before every event in the MIDI file. Good experimental results yielded by the proposed method as well as a comparison of the method with five existing performance-preserving methods from the viewpoints of stego-file quality, payload capacity, and data security show the superiority and feasibility of the proposed method.