US Patent 9396733 Reversible audio data hiding

The present invention provides a method of reversible audio data hiding. The method of data hiding and restoring comprises the steps of: protecting audio by embedding information into the audio according to variance calculation associated to the audio, wherein the quality of the protected audio is degraded after embedding the information into the audio; publishing the protected audio widely as a trial for listen version; and decoding the protected audio for a user who purchased the copyright of the audio by extracting the original audio from the protected audio.