Rate Control with Smoothed Temporal Distortion for a 3 D Embedded Wavelet Video Coder

Embedded 3D wavelet video coding provides good spatial, temporal and quality scalabilities, which is very desirable features for adaptive video delivery and storage. The rate control problem of a 3D embedded wavelet video coder can be converted to a problem of bit-allocation among different wavelet subbands. Considering the structure of wavelet analysis and synthesis, we found traditional 3D wavelet coders could potentially generate nonuniform distortions in the temporal direction of the reconstructed video data, and result in a periodic PSNR (quality) fluctuation across video frames. The periodicity of such PSNR fluctuation in the temporal direction may make visually very uncomfortable user experience. In this paper, we investigate the relationship between the distortion distribution in wavelet subbands and that in the reconstructed data, and proposed a new rate control scheme with smoothed temporal fluctuation. Experimental results show that the proposed scheme can achieve a smoother video quality in the temporal direction while still preserving a comparable average PSNR compared with the 3D SPIHT and 3D EBCOT wavelet video coders.