Abstract
In the digital broadcasting, various data programs are expected as potential attractive services in addition to video and audio. It will become possible to offer the additional services without increasing the total transmission capacity, if the bit rate for video programs can be reduced without deterioration in the picture quality. Some video scenes may not require a full bit rate allocated for a program to obtain sufficient picture quality. By setting up a minimum quantizer scale according to targeted picture quality, which results in VBR coding, some considerable amounts of bit expenses can be saved for additional opportunistic data services while maintaining the required picture quality. Temporal characteristics of the bit savings are also shown, which can be used as fundamental data when considering the additional services.
