Coding of subregions for content-based scalable video

We propose a scheme for coding subregions in video scenes to provide content-based scalable video. For each region, a special color is used to represent the nonobject area, and the resulting frames are coded using conventional video coding algorithms. At the decoder, the region shape is recovered based on chroma keying, and hence, content-based manipulations are made possible. A number of techniques that eliminate boundary artifacts common to region-based coding are presented. In this scheme, no explicit shape coding is needed, and advantages of existing coding algorithms are retained. This scheme was submitted to ISO MPEG-4 and performed very well in the subjective tests.