Denoise a Video

Clean up a grainy, noisy video

Pick a video, choose how hard to denoise its picture and which denoiser to use, and get the same clip back with the grain and sensor noise smoothed away. Everything runs with ffmpeg inside your browser tab — nothing is uploaded, and the tool is free.

Because a denoise filter rewrites every frame, the picture is re-encoded to H.264 (-crf 20, visually near-transparent). The audio is left untouched (stream-copied) whenever the container can hold H.264/AAC — mp4, mov, m4v and mkv keep their container; other inputs (e.g. webm) are converted to MP4 and the audio re-encoded to AAC.

Denoiser and strength

• Denoiser — hqdn3d (the default) is a fast 3D denoiser that averages each pixel both across neighbouring pixels (spatial) and across time (temporal), so grain is smoothed while static detail is kept. nlmeans (non-local means) is a slower, spatial-only denoiser that finds similar patches across the frame; it keeps edges and texture crisper on heavy noise, at the cost of speed.
• Strength (1–100) controls how aggressively noise is removed:
  • Low (10–25) — light grain reduction that keeps the image natural.
  • Medium (30–50) — the general sweet spot for typical camera/sensor noise. The default of 30 lands here.
  • High (60–100) — heavy noise or high-ISO footage; push too far and fine detail can start to smear or look waxy.

Start moderate and raise it only until the grain is gone — over-denoising a video (smeared texture, "plastic" faces) is the usual mistake.

Worked example

You have night-clip.mp4, a hand-held phone clip shot in low light that's full of colour speckle. Load it, leave Denoiser on hqdn3d, and set Strength to 45. You get night-clip-denoised.mp4 — the same footage with the speckle cleaned up and the picture re-encoded to H.264. If faces look a little soft, drop the strength; if heavy grain remains and you'd rather keep edges crisp, switch the Denoiser to nlmeans and try 40.

On the command line the same job is gizza video-denoise --method hqdn3d --strength 45 night-clip.mp4, and the page URL /tools/video-denoise/?method=hqdn3d&strength=45 deep-links to the same pre-filled settings.

Notes and limits

• This is a classic ffmpeg denoiser, not an AI upscaler or restoration model — it reduces grain/noise; it does not invent lost detail or sharpen.
• One setting is applied to the whole clip; there is no per-scene control.
• nlmeans is CPU-heavy in the browser — expect it to be markedly slower than hqdn3d, especially on longer or higher-resolution clips.
• The picture is re-encoded, so the output is not byte-for-byte identical to the source even at low strength. -crf 20 keeps the loss visually negligible.
• Input and output are each capped at 25 MB (the file is processed in your browser's memory).

FAQ