Wind noise reduction
Also known as: wind filter, wind cut
Processing or a camera setting that removes the low rumble wind makes on a microphone, at the expense of some genuine low frequency content.
Updated
What it means
Wind noise reduction attacks the bottom of the frequency range, where turbulence against a capsule puts most of its energy. Removing it makes a track listenable, and removes real low content along with the noise.
Cameras offer it as a setting and editors offer it as processing, and the two are not equivalent. The in camera version is applied before recording and cannot be undone, while processing afterwards keeps the original.
Either way it is a trade rather than a repair. Wind noise is not separable from the rest of the signal, so what comes back is a thinner recording with less rumble rather than a clean one.
How it works in practice
The physical fix beats the processing every time. A Windscreen (dead cat) or a microphone placed out of direct airflow reduces the noise before it is recorded, and nothing applied later matches that.
A high pass filter is the usual tool afterwards, set somewhere above the rumble and below the voice. Exactly where depends on the recording, so it is worth setting by ear rather than by preset.
Processing in stages works better than one aggressive pass, and keeps Normalization from amplifying what the filter left behind. A gentle filter followed by targeted reduction leaves speech more natural than a single setting strong enough to remove everything.
What to watch out for
In camera reduction is a one way decision, so a clip recorded with it enabled cannot be restored if the setting turned out to be too strong for the conditions.
Filtering hard makes voices thin and metallic, which is a different kind of unusable. The rumble is gone and so is the chest of the voice, and a viewer notices the second as readily as the first.
It also cannot help a clipped track. If the wind overran the input and caused Clipping, the distortion is in the recording rather than in the low end, and no filter addresses it.
How RawClip handles it
Camera audio is filtered gently rather than aggressively and sits under the music, because a thin over filtered track is no more usable than a rumbling one. Where wind dominated a clip entirely, the music carries that stretch instead.