Low bit rate software-only wavelet video coding

This paper extends the concept of embedded wavelet still image coding to video coding. The starting point of our work is the SPIHT image codec introduced by Said and Pearlman in [4]. We choose this algorithm because of its simplicity and its high efficiency. Our goal is to streamline its performance in order to explore its potential in real time software-only video coding applications. At low rates, the computational bottleneck of the SPIHT algorithm is in the forward and inverse wavelet transforms. To circumvent this problem we propose a template-based filtering approach which replaces all multiplies by indexing operations, Unlike other multiplier less filtering techniques, the distortion penalty paid for the reduction in complexity is negligible. Furthermore, the proposed technique can efficiently accommodate progressive reconstruction. Specifically, we show that bitwise progressive reconstruction, i.e., updating the output after receiving each new refinement bit, can be achieved with a complexity proportional to the number of nonzero bits transmitted. This approach is specially interesting for data transmission over low bandwidth channels.