Copyright protection of music using digital watermarking based on echo effect

A cocktail digital watermarking scheme based on echo effect is proposed to embedcopyright information into music clips before distribution and to retrieve this informationlater to prove the ownership. The proposed scheme takes advantage of stereo musicto increase retrieval capacity and robustness by embedding data into the left and theright channel using low-bit coding and echo hiding method which have complimentarycharacteristics against various attacks. Furthermore, an exponential time-spread echokernel is proposed for echo hiding to embed data as echoes into music clips while preservingtheir sound natural. By spreading the echo so that it seems like natural roomreverberation, through the use of two channels, the proposed scheme provides satisfactorysound quality and exhibits both efficient retrieval capacity and robustness againstattacks. Experiments show that the proposed system retrieves watermarks with 100%accuracy for all clips. The embedding transparency of the proposed scheme is -1.28in Objective Different Grade (ODG) which is equal to "almost imperceptible". Witha set of 42 attacks supplied by Stirmark Benchmark for Audio (SMBA), the proposedscheme has an average robustness of 0.98 where the ideal value is 1.00, and higherthan the conventional methods.It also shows the robustness against mp3 compression from 192kbps to 128 kbps. With these results, the proposed scheme is shown to beapplicable to music distribution.