视频灰度拉伸程序实现。主要是TMS320DM642的dsp主芯片 与saa7172 和TVP5150的编解码芯片 。。实现图像的编码与解码，实现视频采集与显示。-Video gray stretch program implementation. Mainly TMS320DM642 the dsp main chip with saa7172 and TVP5150 codec chip. . Realize image encoding and decoding for video capt