Comparing motion-interpolation structures for video coding
Atul Puri, Rangarajan Aravind · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1990
This paper considers the topic of video compression at bit-rates around 1 Mbps for digital storage/playback applications. The backbone algorithm employed is the well-known motion-compensated prediction-error coder. This approach is considerably enhanced by the incorporation of conditional motion-compensated interpolation (CMCI), where some of the video frames are encoded with prediction-error coding and the remainder are encoded with motion-compensated interpolation and interpolation-error coding. The advantage of this combined technique is that interpolation errors can be coded with much fewer bits than prediction errors for similar reconstructed-picture quality. We consider two different techniques for estimating motion in CMCI- coded frames. In order to facilitate direct interaction with the bit-stream, the input sequence is divided into groups such that one frame in each group is intra-coded. The arrangement of predictive- and CMCI-coded frames can be varied; a study of these arrangements is the major focus of this paper. Structures with one-, two- and four-frame interpolation are compared. Our results indicate that one-frame interpolation is inferior to two-frame interpolation on complex test material. Four-frame interpolation is comparable in performance to two-frame interpolation as long as the motion is compensable.