Quantized transform-domain motion estimation for sp-frame coding in viewpoint switching of multiview video

The brand-new SP-frame in H.264 facilitates drift-free bitstream switching. Notwithstanding the guarantee of seamless switching, the cost is the bulky size of secondary SP-frames. This induces a significant amount of additional space or bandwidth for storage or transmission. In this paper, our investigation reveals that the size of secondary SP-frames is more severe when the correlation between the two bitstreams becomes smaller. Examples include viewpoint switching in multiview video and bitstream switching in single-view video with complex motion. For this reason, a new motion estimation and compensation technique, which is operated in the quantized-transform (QDCT) domain, is designed for coding secondary SP-frames. Our proposed work aims at keeping the secondary SP-frames as small as possible without affecting the size of primary SP-frames by incorporating QDCT-domain motion estimation and compensation in the secondary SP-frame coding. Simulation results show our proposed scheme overwhelmingly outperforms the conventional pixel-domain motion estimation technique. As a consequence, the size of secondary SP-frames can be reduced remarkably, especially in multiview video and single-view video with complex motion.