本程序实现回音和测量两个DirectShow工具，回音工具使音频播放具有回音效果，测量工具使主对话框中一个正方形区域在调节时闪烁红光，敲击时闪烁绿光。-This procedure echo and measuring the two realize DirectShow tools, echo tools to enable audio playback with echo effects, a measurement tool so that the main dialog box of a