Avidemux Video Filters Guide: Denoise, Sharpen, Crop & More

Video filters in Avidemux are processing steps applied between decoding and encoding. When you re-encode a video, Avidemux decodes each frame, runs it through your filter chain (denoise, sharpen, crop, color tweaks, subtitles and more), then encodes the result. Understanding this chain is the key to cleaner, sharper, better-framed output.

How to use the Filter Manager

  1. Set Video Output to an encoder (e.g. Mpeg4 AVC) — filters do not work in Copy mode.
  2. Go to Video > Filters to open the Filter Manager.
  3. Pick a filter on the left, click the green plus to add it to the active list on the right, then configure it.
  4. Reorder filters with the up/down arrows — the order of the chain changes the result.
Shortcut tip: in Avidemux 2.8.x you can press Ctrl+F to quickly add partial filters, which is handy when you are working with a selection rather than the whole video.

Denoise filters: clean up grainy footage

  • hqdn3d — the most commonly used denoiser; smooths grain and compression noise while preserving detail. A good first choice for noisy low-light footage.
  • FluxSmooth — a lighter spatial/temporal smoother for mildly noisy clips.
  • Temporal Cleaner — uses neighboring frames to remove temporal noise.

Sharpen filters: use sparingly

  • MSharpen — motion-aware sharpening; works well on slightly soft footage.
  • asharp — an alternative adaptive sharpener.
Order matters: always run denoise filters before sharpen filters. Sharpening first amplifies the noise you then try to remove.

Crop and borders

  • Crop — removes black bars or unwanted edges; helpful before resizing.
  • Blacken Borders — fills uneven borders with solid black instead of cropping them away.

Color correction

  • MPlayer eq2 — adjusts brightness, contrast, saturation and gamma. Useful for flat-looking captures.

Subtitles

  • Subtitle (SSA/ASS) — burns SSA/ASS subtitles permanently into the video frame.

Transform

  • Resize — scales the frame to an exact resolution.
  • Fit to size — resizes while keeping the aspect ratio, padding if needed.
Important: every filter requires re-encoding — there is no way to apply filters in Copy mode. Filters are a trade-off: they can greatly improve a video, but re-encoding costs time and (if you push settings too far) quality.

Frequently asked questions

Do video filters work in copy mode?

No. Filters only take effect when you re-encode the video (set Video Output to an encoder such as Mpeg4 AVC). In Copy mode the stream is passed through untouched, so no filter is applied.

Which denoise filter is best in Avidemux?

For most grainy footage, hqdn3d is a solid starting point: it smooths noise while preserving detail. FluxSmooth and Temporal Cleaner are lighter alternatives worth trying on mildly noisy clips; compare them on a short preview before committing.

Why are my filters greyed out?

This usually happens because Video Output is set to Copy. Filters require an encoder: switch Video Output to Mpeg4 AVC or another encoder first, then open Video > Filters.

Can I preview filters before saving?

Yes. The Filter Manager has a preview window so you can see the effect of the filter chain on the current frame before you encode the whole video.