Real-time Watermarking MP3-Compressed Audio
Abstract
Encryption or scrambling of audio data is not enough for controlling access to them, and Watermarking methods should be used for prevention of their unauthorized distribution and thereby preserving rights of their creators. These methods enable controlling copy of audio files and also tracing copied files by hiding Copyright information in audio file. Watermarking MP3-compressed files in Web requires a special kind of watermarking that inserts copyright data directly into bit-stream of MP3 audio. In this thesis, at first, principles of watermarking are explained and then, after reviewing basics of MP3 compression, major audio watermarking methods are discussed and evaluated. The thesis continues with describing a novel technique proposed for watermarking MP3-compressed audio data. In addition, results of evaluating system’s performance are depicted by measuring robustness of embedded data after passing the watermarked signal through various audio processings and attacks intended for removing watermark data from it. Direct extraction of watermark data from compressed file and also nonsusceptibility to asynchronous MP3 frames in Watermark Embedder and Extractor, are among the significant features of the proposed system in comparison to similar methods.
Keywords
Audio Watermarking, Bit-Stream Watermarking, Ownership Authentication, Data Hiding
