抠像先处理背景均匀度，再处理边缘和色溢，最后做前景颜色匹配。主体与背景保持距离能减少绿光反射；边缘问题不要用单一的收缩参数硬修。 Key in passes: even out the background, refine edges and spill, then match foreground color. Keep the subject away from the screen to reduce green bounce; do not solve every edge issue with one choke setting.