实现了mpeg2的编码功能，从.ppm文件转换为mpeg2的视频，并包含了配置文件NTSC.par,供配置图像大小、帧数等参数-Achieved mpeg2 encoding functions, from. Ppm files into mpeg2 video, and includes a configuration file NTSC.par, for the allocation of the image size, fr a me and other parameters