Embedding indexing information in audio signal using watermarking technique

In this paper we propose a watermarking scheme applied to digital audio signals. The goal of the project is to hide information in order to identify both the tracks and the user who request them. This technique is used for automatic identification of audio signals in broadcasted programs. Two are the main features that have to be satisfied: inaudibility and robustness to common editing operations. The algorithm works in a hybrid way: the watermark masking is in the frequency domain while the insertion is in the time domain. This approach allows performing the detection directly in the time domain. In order to insert the watermark the signal is split in frames, each of them hides binary information inserted using a spread spectrum sequence. To improve robustness we use an error correcting code which allows the reduction of error probability. In the paper we discuss first the watermark embedding system, then the detection approach and finally the main results are presented.