This PPT presentation is based on the topic Audio Watermarking
Audio Watermarking is very common topic for seminar presentation.
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Transparency: watermark is not detectable
Robustness: survives digital processing (e.g., compression) and malicious analytical attacks.
Efficiency: low cost implementation using minimal resources
Independence: of both the type and format of multimedia data (e.g., music, speech, video, sample rates, coding scheme, ...)
Temporal watermarking hides watermarks directly into digital audio signals in the time domain.
The spectral audio watermarking applies certain frequency transform, such as FFT, DCT, and DWT, etc, to the data block of the audio signal, and hides the watermark information Into the transformed data block.
Here watermark is embedded by shifting the DC level of the audio signal.
An input signal is divided into frames of fixed length.
DC level of each frame =Mean of a frame-value in the frame
After that a binary watermark sequence generated randomly is introduced to the shifted signal. This is achieved by introducing a DC offset level to each frame in the signal according to the watermark bits.
If the watermark bit is 0, the signal is shifted downward.
If the watermark bit is 1, the signal is shifted upward.