I’m new here, and I’m french. Sorry for my bad english !
I want to mute the original sound only on a part of the video. How can I do ?
When I click on the little loudspeaker on the left of the track, the sound is on or off on the whole video.
Select the track
Add the mute filter
Go to the section you want to mute. set the filter start point. Go to the point where you want to end the mute, set the filter end point. The selected section will be muted.
You can also use the Gain filter with key frames to do the same thing.
The latest version of Shotcut is 19.10.20 available here
Those are available in the latest version. When a filter is selected you can use the key frames panel to trim or key frame filters that are key frame able.