ffmpeg-noise-reduction

CRITICAL GUIDELINES

Windows File Path Requirements

MANDATORY: Always Use Backslashes on Windows for File Paths

When using Edit or Write tools on Windows, you MUST use backslashes (\) in file paths, NOT forward slashes (/).

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Quick Reference

Task	Filter	Command Pattern
Video denoising (best)	nlmeans	-vf nlmeans=s=3:p=7:r=15
Video denoising (fast)	hqdn3d	-vf hqdn3d=4:3:6:4.5
GPU video denoising	nlmeans_vulkan	-vf nlmeans_vulkan
Audio denoising	afftdn	-af afftdn=nf=-25
Adaptive temporal	atadenoise	-vf atadenoise

When to Use This Skill

Use for noise reduction workflows:

• Cleaning low-light or high-ISO footage
• Removing film grain
• Reducing compression artifacts
• Cleaning audio recordings
• Broadcast signal cleanup
• Pre-processing before encoding

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FFmpeg Noise Reduction (2025)

Comprehensive guide to video and audio denoising filters.

Video Denoising

nlmeans - Non-Local Means (Best Quality)

The highest quality software denoiser, using non-local means algorithm.

# Basic denoising
ffmpeg -i noisy.mp4 -vf "nlmeans" output.mp4

# Medium denoising (good default)
ffmpeg -i noisy.mp4 -vf "nlmeans=s=3.0:p=7:r=15" output.mp4

# Strong denoising (very noisy footage)
ffmpeg -i noisy.mp4 -vf "nlmeans=s=5.0:p=7:r=15" output.mp4

# Light denoising (preserve detail)
ffmpeg -i noisy.mp4 -vf "nlmeans=s=1.5:p=5:r=9" output.mp4

# Denoise only chroma (preserve luma detail)
ffmpeg -i noisy.mp4 -vf "nlmeans=s=3.0:sc=5.0:p=7:r=15" output.mp4

Parameters:

Parameter	Description	Default	Range
s	Denoising strength (sigma)	1.0	0-30
p	Patch size	7	1-99 (odd)
pc	Patch size for chroma	0 (same as p)	1-99
r	Research window size	15	1-99 (odd)
rc	Research window for chroma	0 (same as r)	1-99

Strength guidelines:

s value	Use case
1.0-2.0	Light noise, preserve detail
2.0-4.0	Moderate noise (typical)
4.0-6.0	Heavy noise, low light
6.0+	Extreme noise (quality loss)

nlmeans_opencl - GPU-Accelerated NLMeans

OpenCL accelerated version, much faster.

# OpenCL denoising
ffmpeg -i noisy.mp4 \
  -vf "hwupload,nlmeans_opencl=s=3:p=7:r=15,hwdownload,format=yuv420p" \
  output.mp4

# Strong denoising with OpenCL
ffmpeg -i noisy.mp4 \
  -vf "hwupload,nlmeans_opencl=s=5:p=7:r=21,hwdownload,format=yuv420p" \
  output.mp4

nlmeans_vulkan - Vulkan-Accelerated NLMeans (FFmpeg 8.0+)

Cross-platform GPU acceleration using Vulkan.

# Vulkan denoising
ffmpeg -init_hw_device vulkan \
  -i noisy.mp4 \
  -vf "hwupload,nlmeans_vulkan=s=3:p=7:r=15,hwdownload,format=yuv420p" \
  output.mp4

# Full Vulkan pipeline
ffmpeg -init_hw_device vulkan=vk \
  -filter_hw_device vk \
  -hwaccel vulkan -hwaccel_output_format vulkan \
  -i noisy.mp4 \
  -vf "nlmeans_vulkan=s=3" \
  -c:v h264_vulkan output.mp4

hqdn3d - High Quality 3D Denoiser (Fast)

Faster than nlmeans with good results for moderate noise.

# Default settings
ffmpeg -i noisy.mp4 -vf "hqdn3d" output.mp4

# Custom settings (luma_spatial:chroma_spatial:luma_tmp:chroma_tmp)
ffmpeg -i noisy.mp4 -vf "hqdn3d=4:3:6:4.5" output.mp4

# Strong spatial denoising
ffmpeg -i noisy.mp4 -vf "hqdn3d=8:6:6:4" output.mp4

# Strong temporal denoising (for static scenes)
ffmpeg -i noisy.mp4 -vf "hqdn3d=4:3:12:9" output.mp4

# Light denoising
ffmpeg -i noisy.mp4 -vf "hqdn3d=2:1.5:3:2" output.mp4

Parameters:

Parameter	Description	Default	Range
luma_spatial	Luma spatial strength	4.0	0-255
chroma_spatial	Chroma spatial strength	3.0	0-255
luma_tmp	Luma temporal strength	6.0	0-255
chroma_tmp	Chroma temporal strength	4.5	0-255

atadenoise - Adaptive Temporal Averaging

Temporal denoiser that preserves motion.

# Basic temporal denoising
ffmpeg -i noisy.mp4 -vf "atadenoise" output.mp4

# Stronger denoising
ffmpeg -i noisy.mp4 -vf "atadenoise=0a=0.1:0b=0.2:1a=0.1:1b=0.2:2a=0.1:2b=0.2" output.mp4

# Adjust threshold and planes
ffmpeg -i noisy.mp4 -vf "atadenoise=s=9:p=5" output.mp4

Parameters:

Parameter	Description	Default
0a, 1a, 2a	Threshold A for planes 0,1,2	0.02
0b, 1b, 2b	Threshold B for planes 0,1,2	0.04
s	Number of frames to average	9
p	Planes to process	7 (all)

vaguedenoiser - Wavelet Denoiser

Uses wavelet transform for denoising.

# Basic wavelet denoising
ffmpeg -i noisy.mp4 -vf "vaguedenoiser" output.mp4

# Adjust threshold
ffmpeg -i noisy.mp4 -vf "vaguedenoiser=threshold=3:method=soft" output.mp4

# Stronger denoising
ffmpeg -i noisy.mp4 -vf "vaguedenoiser=threshold=6:nsteps=6" output.mp4

Parameters:

Parameter	Description	Default	Values
threshold	Denoising threshold	2	0-inf
method	Thresholding method	hard	hard, soft, garrote
nsteps	Decomposition steps	6	1-32
percent	Percent of full denoising	85	0-100

fftdnoiz - FFT-Based Denoising

Frequency domain denoising.

# Basic FFT denoising
ffmpeg -i noisy.mp4 -vf "fftdnoiz" output.mp4

# Adjust sigma
ffmpeg -i noisy.mp4 -vf "fftdnoiz=sigma=8" output.mp4

# Strong denoising
ffmpeg -i noisy.mp4 -vf "fftdnoiz=sigma=15:block=32:overlap=0.8" output.mp4

owdenoise - Overcomplete Wavelet Denoiser

Another wavelet-based option.

# Basic wavelet denoising
ffmpeg -i noisy.mp4 -vf "owdenoise" output.mp4

# Adjust depth and strength
ffmpeg -i noisy.mp4 -vf "owdenoise=depth=10:ls=3:cs=3" output.mp4

removegrain - RemoveGrain

Classic grain/noise removal (from AviSynth).

# Mode 1 (basic)
ffmpeg -i noisy.mp4 -vf "removegrain=m0=1" output.mp4

# Different modes for different noise types
ffmpeg -i noisy.mp4 -vf "removegrain=m0=17:m1=17:m2=17" output.mp4

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Audio Denoising

afftdn - FFT Denoiser (Recommended)

Powerful audio noise reduction using FFT.

# Basic audio denoising
ffmpeg -i noisy_audio.mp4 -af "afftdn" output.mp4

# Specify noise floor
ffmpeg -i noisy_audio.mp4 -af "afftdn=nf=-25" output.mp4

# Stronger noise reduction
ffmpeg -i noisy_audio.mp4 -af "afftdn=nf=-20:nt=w" output.mp4

# With noise profile (sample noise-only section first)
ffmpeg -i noisy_audio.mp4 -af "afftdn=nr=10:nf=-30:nt=w:om=o" output.mp4

# Adaptive noise floor
ffmpeg -i noisy_audio.mp4 -af "afftdn=nt=c:om=o:bn=9" output.mp4

Parameters:

Parameter	Description	Default	Range
nr	Noise reduction (dB)	12	0.01-97
nf	Noise floor (dB)	-50	-80 to -20
nt	Noise type	w	w=white, v=vinyl, s=shellac, c=custom
bn	Number of noise bands	15	3-33
rf	Residual floor (dB)	-38	-80 to -20
om	Output mode	o	i=input, o=output, n=noise

anlmdn - Non-Local Means Audio Denoiser

Audio equivalent of video nlmeans.

# Basic NLM audio denoising
ffmpeg -i noisy_audio.mp4 -af "anlmdn" output.mp4

# Adjust strength
ffmpeg -i noisy_audio.mp4 -af "anlmdn=s=0.0001" output.mp4

# Stronger denoising
ffmpeg -i noisy_audio.mp4 -af "anlmdn=s=0.001:p=0.01" output.mp4

Parameters:

Parameter	Description	Default
s	Denoising strength	0.00001
p	Patch radius	0.002
r	Research radius	0.006
m	Output mode	o (output)

adeclick - Remove Clicks/Pops

Removes impulsive noise from audio.

# Remove clicks
ffmpeg -i clicked_audio.mp4 -af "adeclick" output.mp4

# Adjust parameters
ffmpeg -i clicked_audio.mp4 -af "adeclick=w=55:o=75" output.mp4

adeclip - Remove Clipping

Repairs clipped audio.

# Fix clipping
ffmpeg -i clipped_audio.mp4 -af "adeclip" output.mp4

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Combined Workflows

Low-Light Video Enhancement

# Denoise + brighten + contrast
ffmpeg -i dark_noisy.mp4 \
  -vf "nlmeans=s=4:p=7:r=15,eq=brightness=0.1:contrast=1.2:saturation=1.1" \
  -c:v libx264 -crf 18 \
  enhanced.mp4

Interview Cleanup (Video + Audio)

# Clean both video and audio noise
ffmpeg -i interview.mp4 \
  -vf "hqdn3d=3:2:4:3" \
  -af "afftdn=nf=-30:nr=10,loudnorm" \
  -c:v libx264 -crf 20 \
  -c:a aac -b:a 192k \
  interview_clean.mp4

Film Grain Removal

# Strong nlmeans for film grain
ffmpeg -i grainy_film.mp4 \
  -vf "nlmeans=s=5:p=7:r=21" \
  -c:v libx264 -crf 18 -preset slow \
  degrained.mp4

# Preserve some grain (artistic choice)
ffmpeg -i grainy_film.mp4 \
  -vf "nlmeans=s=2.5:p=5:r=11" \
  -c:v libx264 -crf 18 \
  light_degrain.mp4

Compression Artifact Removal

# Remove blocking artifacts from highly compressed video
ffmpeg -i compressed.mp4 \
  -vf "hqdn3d=2:1.5:3:2,unsharp=5:5:0.3:5:5:0" \
  -c:v libx264 -crf 18 \
  cleaner.mp4

GPU-Accelerated Batch Processing

#!/bin/bash
# Process multiple noisy videos with GPU

for video in noisy_*.mp4; do
  output="clean_${video}"
  ffmpeg -init_hw_device vulkan \
    -i "$video" \
    -vf "hwupload,nlmeans_vulkan=s=3,hwdownload,format=yuv420p" \
    -c:v libx264 -crf 18 \
    "$output"
done

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Filter Comparison

Video Denoising Speed vs Quality

Filter	Quality	Speed	GPU Option	Best For
nlmeans	Excellent	Slow	Yes (OpenCL/Vulkan)	Final output
hqdn3d	Good	Fast	No	Real-time, previews
atadenoise	Good	Medium	No	Static scenes
vaguedenoiser	Good	Medium	No	Mixed content
fftdnoiz	Good	Medium	No	Periodic noise

Audio Denoising Comparison

Filter	Quality	Speed	Best For
afftdn	Excellent	Fast	All-purpose
anlmdn	Good	Medium	Speech
adeclick	Specialized	Fast	Clicks/pops

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Parameter Tuning Tips

Video Denoising

1. Start conservative - Begin with s=2-3, increase if needed
2. Preserve edges - Lower patch size (p=5) preserves more detail
3. Test on samples - Process 10-second clips first
4. Consider GPU - nlmeans_opencl/vulkan are 5-10x faster
5. Match content - Static scenes tolerate stronger temporal denoising

Audio Denoising

1. Find noise floor - Listen to quiet sections
2. Use appropriate type - White noise vs vinyl vs custom
3. Don't over-process - Artifacts can be worse than noise
4. Check residual - Use om=n to hear what's being removed

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Best Practices

1. Denoise before encoding - Noise compresses poorly
2. Preserve some texture - Over-denoising looks artificial
3. Match source quality - Don't denoise clean footage
4. Use GPU when available - Massive speed improvement
5. Combine filters carefully - Multiple denoisers can cause artifacts
6. Test different filters - Content-dependent results

This guide covers noise reduction for 2025. For video analysis and detection, see ffmpeg-video-analysis. For hardware acceleration, see ffmpeg-hardware-acceleration.