Data embedding in audio using time-scale modification
A new framework for data embedding in audio is proposed. The basic idea of the algorithm is to change the length of the intervals between salient points of the audio signal to embed data. The intervals are quantized and the data is embedded in the quantization indices. In our particular implementation, we use the wavelet extrema of the signal envelope as the salient points. We propose novel ideas for practical implementation that can be used by other data embedding schemes as well. The algorithm is robust to common audio processing operations, e.g., mp3 lossy compression, low pass filtering, sampling rate conversion, and time-scale modification (TSM). The perceptual quality of the audio signal after embedding the data depends on the technique used for TSM.