Research On Video Format Conversion System

Video format conversion is a key technology in digital video process. For most types of monitors, there are many differences between the input video format and the format which the monitor devices demand, which include scan rate, scan standard, resolution, etc. To solve these problems, many algorithms related to video format conversion have been put forward, and the video/image standard conversion ASIC is also becoming an important module of monitor system.This paper proposes a new way for video format conversion can realize the conversion from interlaced scan to progressive scan, frame rate up conversion and dimension scaling, turn video sequences corresponding to different standards into the targeted standard and play them in real time. Furthermore, the function of man-machine intercommunication interface is integrated in this software.All the monitors ask for high-quality as well as cost-efficient standard conversion algorithms. After the simulation, comparison and analysis of the previous algorithms, the following algorithms are proposed in this paper:(1) An optimized motion adaptive de-interlacing algorithm which is based on the field averaging and cross filtering;(2) All-phase image interpolation algorithm based on DCT. As a good integration of DCT and All-phase philosophy, a family of separable interpolation kernel, which is constructed by cosine function, is put forward. Look-up-table method is then discussed for real time realization. The subjective and objective experiments show that better image quality is obtained by using the proposed interpolation kernel than by using 6×6 cubic convolution interpolation kernel;(3) Linear frame-up conversion algorithm based on motion compensation. A high performance and easily realized motion estimation algorithm called the improved 3-step search algorithm is put forward. It can obtain exact motion vectors. For the correctness of the motion vectors, the motion vectors are revised by median filtering.