A Symbol Based Watermarking Approach for Spread Spectrum Audio Watermarking Methods

This paper proposes an high embedding capacity symbol based audio watermarking process. The traditional watermark embedding processes require longer duration audio sequence in order to accommodate all the input watermark bits. Shorter duration audio sequences which are like advertisements in Television & Radio should allow the embedding of a complete watermark at least once to be able to correctly identify the owner or content. A symbol based approach for spread spectrum based audio watermark methods has been proposed in order to reduce the required size of the audio sequences for watermarking. Each group of watermark bits called as a symbol are mapped to a unique pseudo-random sequence. These PN sequence are used for actual embedding in Spread Spectrum based watermarking technique. This process while reducing the size of the audio sequence required, it also helps in reducing the errors in longer duration audio as it can allow redundant addition of watermark. An error correction method is also added to further reduce the symbol errors that are caused due to the intentional and unintentional watermark removal attacks.