There is no sound solution for 3.5mm headphones in Ubuntu system

Applicable system versions Ubuntu 16.04, Ubuntu 18.04, Ubuntu 22.04 +

Installation command:

sudo apt install pavucontrol
pavucontrol

Start interface:

Select Volume Control - Configuration - Analog Stereo Duplex

Select Volume Control - Output Devices - Line Out or Headphones

 选择 Volume Control - Playback - VLC media player - Analog Stereo

The above can play the sound from the multimedia player in the headphones, and you can also see an additional Line Out option in the system's sound settings.