There are two ways：
- Click "Mixer" in the right sidebar and click the mixing button to turn on or off mixing. Yellow means on , gray means off .
- Click the speaker button in the source window to turn on or off mixing
Mix is on
Mix is off
- After switching the video to PGM, the video will automatically turn on mixing by default. When the video is cut out of PGM, mixing will be automatically turned off by default