METHOD FOR CODING VIDEO FRAME SEQUENCE, SYSTEM AND MEDIUM USABLE BY COMPUTER

摘要

PROBLEM TO BE SOLVED: To provide a method and a system to discriminate dynamically a size of a picture group (GOP) as a function of a picture change activity in a video frame sequence and to provide a product of a computer program. SOLUTION: In the image statistics with respect to one or plural intra-frame characteristics of a video frame sequence, a preset threshold value (331) is compared to decide whether the statistics is conducted in a current GOP or a new GOP is started. A frame in the video frame sequence is intra-coded and each of succeeding frames of a variable number is subject to 2-way prediction coding (B). Each B frame in succession to an I frame is coded from the I frame by using only forward prediction motion estimation. On the occurrence of prescribed deterioration in a picture, a new GOP is started for the processing. One example of an intra-frame characteristic to be monitored is the number of macro blocks that are intra-coded in each coded B frame. This number is compared with a threshold value and the threshold value may be a part of a total number of macro blocks in a frame.