A rate control strategy for embedded wavelet video coders in an MPEG-4 framework

Embedded wavelet encoders possess a number of interesting features for video encoding applications. Among those, we can mention-the ability to encode a picture with precise control over the bit-rate. This differs significantly from the DCT-based methods adopted in the MPEG-4 standard, in which the rate cannot be directly set, being controlled by the quantizer step size instead. We investigate, rate-control strategies for embedded wavelet encoders in an MPEG-4 framework, that take advantage of the precise control that can be obtained for the bit-rate in such coders. We also investigate the use of successive approximation vector quantization in them for replacing the traditionally used successive approximation scalar quantization. The results are encouraging showing that both the use of vector quantization and the adoption of an adequate rate control strategy can improve both objective and subjective quality of video sequences encoded using embedded wavelet encoders