Reduced-complexity rate-distortion optimization of multiresolution motion field and prediction residual

Joint coding of motion information and motion compensation residual information in a rate-distortion optimisation setting can entail a prohibitive computational cost. For a multiresolution motion compensation framework, we propose a fast and efficient scheme that finds the displacement vectors while accounting for the rate-distortion performance of residual coding. The proposed scheme is compared with a popular H.263 test model, with its advanced prediction mode enabled. For various common QCIF video test sequences, the proposed scheme outperforms H.263 by between 0.5-1.1 dB in PSNR, while using roughly a 15% higher complexity than H.263. The similarity of our framework to H.263 renders our results useful for understanding the performance complexity trade-offs of encoders for the current H.263 standard and its descendents.