Types of Watermarking

Digital audio watermarking:
Herein, the watermark i.e. the digital audio watermark consists of the information pertaining not to the only to the creator of the audio information that could be any one of several forms of song, music etc., but also to the authenticated user of the audio information. This allows that particular information to be used by only the authorized user and no one else. The watermark can also be used for secondary applications other than authentication.e.g. Providing information about the song, album, style of tunes, etc. This watermark is useful in voice conferencing halls to indicate the person who is speaking at the moment .
Digital video watermarking:
A watermark inserted in a video signal can be used for DVD copy protection. First of all; the watermark should satisfy the requirements of strength and imperceptibility. Besides this, it can be bestowed on to convey the information to restrict copying in many ways such as copy never i.e. The DVD is copy protected, copy no more i.e. it is possible to copy a finite number of times, copy liberally i.e. it can be copied any number of times, copy only once. The design depends upon the content in the DVD. A general process of digital video watermarking consists of inserting a group of bits along with the video frame to be transmitted.
Image watermarking:
For watermarking a still image, the watermark is directly inserted on the picture of information itself such as colour, brightness, and luminescence etc. the watermark may be inserted directly onto the pixels.
Text watermarking:
Text watermarking is the process of inserting watermark into the text for preserving the creator’s identity. This is especially applicable to such valuable texts such as poetry. An earlier form of watermarking the texts was accomplished by inserting spaces in specific parts of the text. The disadvantage associated with this form of watermarking was that it was quite is to remove the watermark