Hey,
I filmed quite a few scenes at school where there is a decent amount of background noise. I am not sure if or which filter would reduce background noise and how to do it. A few tips would be greatly appreciated and Merry Christmas!!
First choice would be to try High Pass
Then maybe Limiter and Compressor…
If you can’t obtain a better result, try with Audacity.
How do I get the audio into Audacity?
Just drag the video file on an audio track.
Then export in ogg maybe to test.
if not enought, I don’t know which lossless format to use… FLAC maybe?
Just saw this. Thanks, I’ll give it a try.
Okay, I’m having a stupid attack. 
I’m not sure exactly what you mean by drag the video file on an audio track. I tried dragging the .mp4 into an Audacity window and I received an error message. that it’s an "advanced audio coding file and that I need to convert it to a supported file, such as .wav, etc. I also opened the file in Shotcut and split the video and audio into two separate files. I can’t drag the audio track into Audacity and I can’t find a way to simply save the audio track as a .wav.
If you want to open mp4 and other advanced audio files with Audacity this link will tell you what you need to do.
https://manual.audacityteam.org/man/installing_and_updating_audacity_on_windows.html#winff
For adding mp4 to audio track on Shotcut, on the timeline, you just have to add an audio track (from the timeline’s menu or adding a mp3 then erasing it).
Then Ctrl + o the mp4 and drag it to the audio track
In the Export window, click on one of the Audio presets, like WAV.
This will just export the audio, no video.
There is no need to put the MP4 to an audio track.
Use that WAV file in Audacity or any other DAW software.
Then once done, import the edited file back into Shotcut.