The following reference https://www.youtube.com/watch?v=5NZ0qwp2L04, I made some changes, let it understood some.
- Search the App Store for PulseAudio Volume Control on the Ubuntu Store homepage https://apps.ubuntu.com/cat/applications/pavucontrol/or directly click apt:// Pavucontrol Jump to the store installation.
- To enter this software, click on the tab input Devices, then click on the bottom show, switch to all Input Devices.
- Now let your computer play a sound, you will see one of the devices below the progress bar is fluctuating, the larger the sound, the longer the progress bar, remember the device name.
- Then let the wave of the bar be yellow (different from gray), click on the right three buttons in the first implementation switch.
- In Kazam's perference, select speakers for the device name above. That's good, thanks for watching.
Ubuntu under Kazam Recording screen no sound solution