Troubleshoot Ubuntu smplayer playback video without sound problems

Issue: Ubuntu Kylin 14.04 system is installed by default, SMPlayer play video is normal, but recently may be due to some mis-settings, causing SMPlayer to play any format video is silent.
Workaround: Since ALSA is the bottom of the Linux sound system, first change the SMPlayer "preferences, audio-and output driver" setting from PulseAudio to Alsa, to see if there is a sound. If there is no sound, first check the ALSA mixer volume settings, and then check the PulseAudio volume settings.

1. Check the ALSA mixer settings

$alsamixer
The first four master, headphone, speaker, and PCM cannot be mm (mute), if mm, the left and right arrows move to the item, press the M key, and then press the up and down arrows to adjust the volume.

2. Check the Pluseaudio volume control

$sudo Apt-get Install Padevchooser
$pavucontrol
Check that the volume of the PulseAudio audio output device (especially the "built-in audio analog stereo") is muted or volume is 0

3. Check the system volume control

This needless to say, the taskbar volume control.

Troubleshoot Ubuntu smplayer playback video without sound problems