Video volume

The volume of video and audio should be managed separately.

On the Timeline, select the video that you want to edit.
Click the Clip Properties button to open the video properties for the selected clip.
Drag the Volume slider to set the volume for the selected clips. 100% is the original volume.
To mute the clip, uncheck the option on the right of the Volume slider.
If the clip has a lot of volume peaks, use the Normalize option to raise the volume of quiet parts.