PCM Encoding and a Spread Spectrum Modulation in the Watermarking System

PCM Encoding and a Spread Spectrum

Modulation in the Watermarking System

The watermarking of digital data has become very popular

approach for intellectual property rights protection. Several

watermarking techniques were developed and a large amount

of methods were proposed, but still the most of known ways

to protect data are far from ideal. The digital data of the

various types such as text, images, audio, and video can be

processed by the watermarking procedure. In general, all

types of data watermarking techniques have similar simple

ideas – to hide a set of owner’s data within the materials,

which should published, with the purpose to be able to prove

his ownership. The requirements for watermarked data

quality and safety for all types are also the same. Watermark

should be imperceptible for unauthorized user, should not

affect an original data quality and should be robust against

various types of attacks [1].

Audio watermarking is concerned with the insertion of a

signal of known information or characteristics in an audio

signal in an imperceptible way. Detection of the embedded

watermark helps in authenticating the audio, identifying

illegal copies of the audio, and detecting unauthorized

changes made to the audio. While data embedding in an audio

signal, or audio steganography, resembles audio

watermarking in many ways, the former has applications in

covert and/or secure communication of battlefield

information, confidential financial transactions, etc., requiring

a large payload capacity. Watermarking, on the other hand, is

primarily used for copyright protection of digital products

that require embedding a small amount of information [2].

To be effective in the general application of copyright

protection, a watermarking technique must satisfy three major

criteria, namely, the watermarked audio is perceptually

indistinguishable from the original audio, the watermark is

robust so that a user is unable to extract the watermark

without destroying the audio, and the watermark is

ownership.