A Fast Multisprite Generator with Near-Optimum Coding Bit-Rate

Sprite coding, which can increase the coding efficiency of backgrounds greatly, is a novel technology adopted in MPEG-4 object-based coding. Due to the geometric transformation applied to each nonreference frame in the procedure of sprite coding, the generated sprite is distorted and the available view angles relative to the reference frame are restricted. These problems can be resolved by using multiple sprites. An optimal multisprite generator has been proposed by Farin et al., but the optimal method requires high computation in the sprite coding cost. To treat this disadvantage, a fast multisprite partition algorithm is proposed in this paper based on frame translations and scalings. The proposed algorithm divides a video sequence into several subsequences, and a sprite is generated from each subsequence. The experimental results show that the executing speed of the proposed method is increased by 10 to 190 times than the optimal method, with the total size of generated sprites is slightly higher and the qualities of generated sprites are preserved.