The work has now moved on to Scalable Wavelet coders. We are looking at SNR and bandwidth scalability and are currently able to demonstrate that a two layer scalable wavelet coder suffers only a small SNR penalty compared to a single layer codec at the same bit-rate. In comparison, a MPEG-based scalable codec suffers a larger penalty. We are also currently looking at transcoding to and from wavelet representations, signal processing in the wavelet domain and multi-channel wavelet coding, including a study of the correlation between wavelet representations of 2 or more audio channels. It is also possible to use the wavelet decoder in stand-alone mode as a musical instrument synthesiser.
Results are encouraging and interesting.
An important element of the work is to investigate what channel coding strategies are suitable to cope with lost packets and reconstruction of missing data. The project also involves work on Video Coding over Mbone undertaken with our partners, University of Bristol and University College London. Extensive user-groups include Virgin and Chrysalis Records and H2O Enterprises. Among the achievements are the first known published works on sounds generated entirely from Fractal models and the implementation and improvement of algorithms to extract Fractal descriptions from sounds. We are currently examining Wavelet decomposition of signals with Fractal geometric properties as a means to establish a relationship between Fractals and Wavelets.