DM6437 DSP实现图像叠加（即画中画）功能。代码已测试，性能稳定，效果颇佳。内含如何配置寄存器的详细说明。-DM6437 DSP for image overlay (ie, Picture in Picture) function. Code has been tested, stable performance, the effect is quite good. Contains a detailed descr iption of how the configuration reg