An Audio/Speech Watermarking Method for Copyright Protection

Protecting the copyrights of multimedia content is necessary to discourage unauthorized distribution or sharing of the content over Internet. Digital watermarking helps in protecting the copyrights while reduces the monetary loss to the content owner. Digital watermarking is the process of inserting owner or customer related unique information as a watermark into a host signal such as audio or speech or image or video without disturbing perceived quality of the host signal. One of the main characteristic of a digital watermarking is to enable accurate watermark detection even if the multimedia content undergoes some changes that may eliminate the watermark from the content. These changes include compression, rate conversion, filtering and noise addition etc. In this paper, we present a watermarking method that can be used for watermarking both audio and speech. Watermark embedding is done using singular values obtained by applying Singular Value Decomposition(SVD) on the structured Discrete Wavelet Transform(DWT) coefficients, correlation peak to side-lobe ratio(PSLR) metric is used to detect watermark from the correlation output, which is computed between the singular values obtained from the watermarked content and each watermark in the database. This method has been implemented in MATLAB and tested on various audio and speech tracks against various signal processing modifications. The experimental results prove the robustness of proposed method while satisfying the imperceptibility criteria.