| 摘要 |
PURPOSE: To prevent deterioration in image quality of a reproduced image by conducting compression coding for frames of 1st GOP structure and using 2nd and 3rd GOP structures in the case that no I frame is formed even when the coding is forcibly continued. CONSTITUTION: A picture is made up of frames I coded by an in-fame compression coding method, frames P coded by a forward prediction inter-frame compression coding method, and frames B coded by a two-way prediction inter-frame compression coding method. Let number of frames for a period of appearance of the frames I be N, and let number of frames for a period of P frames appearing at a prescribed frame interval from the I frame be M. Then let frames from one I frame to a succeeding I frame be one picture group GOP, and 1st, 2nd and 3rd GOPs are defined, where they have difference from N and M. When compression coding is conducted under the 1st GOP structure and no I frame is formed even when it is continued forcibly, the compression coding is conducted by using the 2nd or 3rd GOP structure. |
