Audio Watermarking Using Dc Level Shifting

Multimedia data are mainly in digital form due to advantages of digital domain compared to analog domain. These advantages can be grouped into several categories. Firstly, digital multimedia data authoring is easier and more robust to authoring errors. Editing and modifying data can be accomplished relatively easily. Secondly, digital multimedia data can be delivered over computer networks with almost no error and no interference. Thirdly, software instead of hardware processing of digital data increases the reconfigurability of systems ([1], [2]). On the other hand, there are several disadvantages of digital media distribution. Digital data can be copied without any loss in quality and content. This poses a big problem for the protection of Intellectual Property (IP) rights of the copyright owners. Watermarking is a solution to the previously defined problem. It can be defined as embedding digital data (generally information about origin, destination, access level of the data) imperceptibly into the host multimedia data. Several watermarking methods exist for different media like image, video, audio, text, polygonal models, etc. Watermark embedding domain can be spatial, frequency or both. In every method, embedding watermark data as robust as possible without being perceptible is desired. This requirement necessitates the utilisation of human sensory models (HVS: Human Visual System, HAS: Human Audible System...) and characteristics in watermark embedding process. More information about watermarking in general and audio watermarking can be found at [3], [4], [5], [6], [7] and [8].