Rate control for an embedded wavelet video coder

Embedded coders provide a better rate-distortion tradeoff while the coded bit stream can be truncated at any point without a significant perceptible distortion. We investigate rate control for an embedded wavelet video coder by converting the rate control problem to a bit allocation problem for each frame. Then, a computationally efficient rate control algorithm is derived by exploiting the rate-distortion performance of the embedded wavelet coder and the frame dependency between the reference frame and the predictive frame. Experiments are performed to demonstrate the superior performance of the embedded wavelet video coder with the proposed rate control scheme. It is shown that the proposed rate control strategy outperforms the fixed allocation rate control by 0.1-0.4 dB for a variety of sequences, and the performance gain can be as large as 1.3-2.7 dB around scene changes