VIDEOKODER MIT ZWEI SCHICHTEN

摘要

PCT No. PCT/GB93/00643 Sec. 371 Date Oct. 7, 1994 Sec. 102(e) Date Oct. 7, 1994 PCT Filed Mar. 29, 1993 PCT Pub. No. WO93/20650 PCT Pub. Date Oct. 14, 1993A layered coder includes a lower resolution predictive encoder (102) and a higher resolution encoder (402) providing coded low and high resolution signals at lines (110) and (218) respectively. The prediction error of the lower resolution predictive encoder (102) is provided as a prediction error estimate to the higher resolution encoder (402), the prediction error estimate being subtracted from the prediction error generated in the higher resolution predictive encoder (402) by the subtractor (210). This difference from the subtractor (404) is coded by the coder (212) whose output is made available on the line (218). The prediction error estimate from the up sampler (130) is added to the output from the decoder (220) by an adder (406) in order to complete the predictive loop of the higher resolution predictive encoder (402). The prediction error estimate can also be subtracted from the prediction error of the higher resolution predictive encoder in the transform domain. The layered coder makes available both higher and lower resolution coded signals, with good coding efficiency as the coding information obtained from the lower resolution encoder (102) is used in the coding carried out by the higher resolution predictive encoder (402).