Multimedia transmissions over heterogeneous networks require a high degree of flexibility from video compression systems. They are expected to be fully scalable, that is to say to be able to partly decode a video bitstream and to get a reconstruction quality proportional to the received amount of information. To achieve this functionality, we propose a video codec based on 2D+t subband decomposition. Groups of frames are first temporally filtered using motion compensation and then spatially decomposed with wavelets. The spatiotemporal coefficients are further scanned and compressed using a new SPIHT-like strategy, namely fully scalable zerotree coding, together with arithmetic encoding, which provides a combination of temporal, spatial and SNR scalability. In addition, scalable motion vector coding ensures a fully progressive bitstream.
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