Note: This is in Ubuntu 16.04
Removing the static noise picked up by the microphone is essential before uploading youtube videos since youtube does not allow editing audio track after the upload. It stopped allowing annotations in videos too, so the only way to remove noise after uploading is to take down the video and upload a new video. Unfortunately I had to do the same, just explaining here how to do the editing using freeware in ubuntu.
To remove noise, we need two software,
sudo add-apt-repository ppa:sunab/kdenlive-release sudo apt-get update sudo apt-get install kdenlive
Initial step is two create a audio file which is free from noise from the video file using Audacity.
Open Audacity-> File->Open (open video file)
Deselect the noise (click anywhere outside the selection); Effect->Noise Reduction: Step 2 – OK (keep default settings or change Noise reduction settings in db for more attenuation)
File->Export Audio->Save as noise_free.mp3
We use kdelive to merge the noise free audio track to the video track.
Drag the video to Video 1, drag noise_free.mp3 to Audio 1, mute Video 1 audio track. Go to project Monitor as press play button to check the new audio.
To save the new video Click on Render-> Render into a file (keep default settings or change settings whichever needed for file format)
See the comparisons below.