“MPEG-4 Very Low Bitrate Video Coding System by Adaptively Using Sprite”

MPEG-4, a new audio-visual coding standard has strong compression tools, such as sprite coding. We have focused on sprite coding and proposed “Sprite Mode”. In sprite mode, video sequence is divided into foreground object and background object. Foreground object is compressed using MPEG-4 object coding, while background object is compressed using sprite coding. Sprite mode does not always adopt any video sequence such that images having still camera motion can be compressed in enough quality in low bitrate. So, in this paper, we developed new MPEG-4 video encoder using sprite coding. In the proposed MPEG-4 encoder, multi-mode coding is newly proposed. Video shot suitable for conventional coding method is coded by normal mode (conventional method), while video shot suitable for sprite coding is coded by sprite mode. These two modes are automatic selected in any video sequences. We improved the processing flow using stuck system in order to consequently process video such as AVI format. We improved global motion detection algorithm, foreground object and background sprite generation algorithm. Then we proposed the simple rate-control for sprite mode. Then, we have some experiment on MPEG-4 video coding. The result shows effectiveness’ of proposed encoder in low bitrate coding.