Agent skill

ffmpeg-color-grading-chromakey

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Install this agent skill to your Project

npx add-skill https://github.com/JosiahSiegel/claude-plugin-marketplace/tree/main/plugins/ffmpeg-master/skills/ffmpeg-color-grading-chromakey

SKILL.md

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 (/).

Quick Reference

Task Command
Green screen removal -vf "chromakey=0x00FF00:0.3:0.1"
Blue screen removal -vf "chromakey=0x0000FF:0.3:0.1"
Apply LUT -vf "lut3d=cinematic.cube"
Color curves -vf "curves=preset=vintage"
Adjust saturation -vf "eq=saturation=1.5"
Hue shift -vf "hue=h=30"
White balance -vf "colortemperature=6500"

When to Use This Skill

Use for color manipulation operations:

  • Removing green/blue screen backgrounds
  • Applying LUT color grading
  • Color correction and enhancement
  • Creating cinematic color looks
  • HDR/SDR conversions
  • Color keying for compositing

FFmpeg Color Grading & Chromakey (2025)

Complete guide to color manipulation, green screen removal, LUT grading, and advanced color effects with FFmpeg.

Green Screen (Chromakey) Removal

Basic Chromakey

bash
# Remove green screen (standard green 0x00FF00)
ffmpeg -i foreground.mp4 -i background.mp4 \
  -filter_complex "[0:v]chromakey=0x00FF00:0.3:0.1[fg];[1:v][fg]overlay" \
  -c:v libx264 -crf 18 output.mp4

# Parameters:
# - color: The key color (hex 0xRRGGBB)
# - similarity: How close to key color (0.0-1.0, lower = more precise)
# - blend: Edge softness (0.0-1.0, higher = softer edges)

Chromakey Parameter Tuning

bash
# Tight key (clean edges, may leave green fringe)
ffmpeg -i green_screen.mp4 -i background.jpg \
  -filter_complex "[0:v]chromakey=0x00FF00:0.1:0.0[fg];[1:v][fg]overlay" \
  output.mp4

# Loose key (removes all green, may eat into subject)
ffmpeg -i green_screen.mp4 -i background.jpg \
  -filter_complex "[0:v]chromakey=0x00FF00:0.5:0.2[fg];[1:v][fg]overlay" \
  output.mp4

# Balanced (recommended starting point)
ffmpeg -i green_screen.mp4 -i background.jpg \
  -filter_complex "[0:v]chromakey=0x00FF00:0.3:0.1[fg];[1:v][fg]overlay" \
  output.mp4

Blue Screen Removal

bash
# Remove blue screen
ffmpeg -i blue_screen.mp4 -i background.mp4 \
  -filter_complex "[0:v]chromakey=0x0000FF:0.3:0.1[fg];[1:v][fg]overlay" \
  output.mp4

# Chroma blue (common broadcast blue)
ffmpeg -i footage.mp4 -i background.mp4 \
  -filter_complex "[0:v]chromakey=0x0047AB:0.3:0.15[fg];[1:v][fg]overlay" \
  output.mp4

Sample Green Screen Colors

Name Hex Use Case
Pure Green 0x00FF00 Digital green screens
Chroma Green 0x00B140 Professional film/TV
Light Green 0x90EE90 Lighter backgrounds
Pure Blue 0x0000FF Digital blue screens
Chroma Blue 0x0047AB Professional broadcast

Advanced Chromakey with Despill

Green spill removal (green reflection on subject):

bash
# Remove green screen with despill
ffmpeg -i green_screen.mp4 -i background.mp4 \
  -filter_complex "\
    [0:v]chromakey=0x00FF00:0.3:0.1,\
    colorbalance=gs=-0.1:gm=-0.1:gh=-0.1[fg];\
    [1:v][fg]overlay" \
  output.mp4

# More aggressive despill using hue filter
ffmpeg -i green_screen.mp4 -i background.mp4 \
  -filter_complex "\
    [0:v]chromakey=0x00FF00:0.3:0.1,\
    hue=s=0.9[fg];\
    [1:v][fg]overlay" \
  output.mp4

Colorkey Filter (Transparency)

Colorkey creates actual transparency (alpha channel) instead of compositing:

bash
# Create transparent video (WebM with alpha)
ffmpeg -i green_screen.mp4 \
  -vf "colorkey=0x00FF00:0.3:0.1" \
  -c:v libvpx-vp9 -pix_fmt yuva420p \
  output_transparent.webm

# Create transparent PNG sequence
ffmpeg -i green_screen.mp4 \
  -vf "colorkey=0x00FF00:0.3:0.1" \
  frame_%04d.png

Colorkey vs Chromakey

Feature colorkey chromakey
Output Alpha channel Composited
Format Requires alpha support Any format
Use Create masks Direct compositing
Formats WebM, PNG, ProRes 4444 MP4, MKV, etc.

LUT Color Grading

Apply 3D LUT

bash
# Apply .cube LUT file
ffmpeg -i input.mp4 \
  -vf "lut3d=cinematic.cube" \
  -c:v libx264 -crf 18 output.mp4

# Apply .3dl LUT
ffmpeg -i input.mp4 \
  -vf "lut3d=film_look.3dl" \
  output.mp4

# Specify interpolation method
ffmpeg -i input.mp4 \
  -vf "lut3d=lut.cube:interp=trilinear" \
  output.mp4

LUT Interpolation Methods

Method Quality Speed
nearest Lowest Fastest
trilinear Good Fast
tetrahedral Best Slower
bash
# High quality LUT application
ffmpeg -i input.mp4 \
  -vf "lut3d=film.cube:interp=tetrahedral" \
  -c:v libx264 -crf 18 output.mp4

Blend Original with LUT

bash
# 50% LUT strength
ffmpeg -i input.mp4 \
  -filter_complex "\
    [0:v]split[a][b];\
    [a]lut3d=cinematic.cube[graded];\
    [b][graded]blend=all_expr='A*0.5+B*0.5'" \
  output.mp4

# Variable LUT intensity using colorbalance
ffmpeg -i input.mp4 \
  -vf "lut3d=lut.cube,colorbalance=rs=0:gs=0:bs=0" \
  output.mp4

Popular LUT Styles

Create common looks without external LUTs:

bash
# Teal and Orange (blockbuster look)
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=0.1:gs=-0.1:bs=-0.2:rm=0.05:gm=-0.05:bm=-0.1:rh=0.1:gh=-0.05:bh=-0.15" \
  output.mp4

# Vintage/Retro
ffmpeg -i input.mp4 \
  -vf "curves=preset=vintage,eq=saturation=0.8:contrast=1.1" \
  output.mp4

# High Contrast Cinematic
ffmpeg -i input.mp4 \
  -vf "eq=contrast=1.2:brightness=-0.05:saturation=1.1,unsharp=5:5:0.8" \
  output.mp4

# Desaturated/Bleach Bypass
ffmpeg -i input.mp4 \
  -vf "eq=saturation=0.5:contrast=1.3:brightness=-0.02" \
  output.mp4

# Warm/Golden Hour
ffmpeg -i input.mp4 \
  -vf "colortemperature=5000,eq=saturation=1.2:brightness=0.05" \
  output.mp4

# Cool/Moonlight
ffmpeg -i input.mp4 \
  -vf "colortemperature=8000,eq=saturation=0.9:brightness=-0.05" \
  output.mp4

Color Curves

Preset Curves

bash
# Vintage look
ffmpeg -i input.mp4 -vf "curves=preset=vintage" output.mp4

# Cross process (film developing effect)
ffmpeg -i input.mp4 -vf "curves=preset=cross_process" output.mp4

# Negative image
ffmpeg -i input.mp4 -vf "curves=preset=negative" output.mp4

# Increase contrast
ffmpeg -i input.mp4 -vf "curves=preset=strong_contrast" output.mp4

# Lighter
ffmpeg -i input.mp4 -vf "curves=preset=lighter" output.mp4

# Darker
ffmpeg -i input.mp4 -vf "curves=preset=darker" output.mp4

# Linear contrast
ffmpeg -i input.mp4 -vf "curves=preset=linear_contrast" output.mp4

# Medium contrast
ffmpeg -i input.mp4 -vf "curves=preset=medium_contrast" output.mp4

Custom Curves

bash
# S-curve for contrast (RGB)
ffmpeg -i input.mp4 \
  -vf "curves=all='0/0 0.25/0.20 0.5/0.5 0.75/0.80 1/1'" \
  output.mp4

# Lift shadows, lower highlights
ffmpeg -i input.mp4 \
  -vf "curves=all='0/0.05 0.5/0.5 1/0.95'" \
  output.mp4

# Per-channel curves (R, G, B)
ffmpeg -i input.mp4 \
  -vf "curves=r='0/0 0.5/0.6 1/1':g='0/0 0.5/0.5 1/1':b='0/0 0.5/0.4 1/1'" \
  output.mp4

# Crushed blacks (film look)
ffmpeg -i input.mp4 \
  -vf "curves=all='0/0.03 0.15/0.15 0.5/0.5 0.85/0.85 1/1'" \
  output.mp4

Color Balance

colorbalance Filter

bash
# Warm highlights, cool shadows
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=-0.1:gs=-0.05:bs=0.1:rh=0.1:gh=0.05:bh=-0.1" \
  output.mp4

# Parameters:
# rs/gs/bs = red/green/blue shadows (-1 to 1)
# rm/gm/bm = red/green/blue midtones (-1 to 1)
# rh/gh/bh = red/green/blue highlights (-1 to 1)

Common Color Balance Presets

bash
# Orange and Teal (cinematic)
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=0.15:bs=-0.15:rh=0.1:bh=-0.1" \
  output.mp4

# Warm overall
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=0.1:rm=0.05:rh=0.1:bs=-0.05:bm=-0.03:bh=-0.05" \
  output.mp4

# Cool shadows, warm highlights (split toning)
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=-0.1:bs=0.1:rh=0.15:bh=-0.1" \
  output.mp4

Hue and Saturation

hue Filter

bash
# Rotate hue by 30 degrees
ffmpeg -i input.mp4 -vf "hue=h=30" output.mp4

# Increase saturation
ffmpeg -i input.mp4 -vf "hue=s=1.5" output.mp4

# Decrease saturation (desaturate)
ffmpeg -i input.mp4 -vf "hue=s=0.5" output.mp4

# Adjust brightness
ffmpeg -i input.mp4 -vf "hue=b=0.1" output.mp4

# Animated hue rotation
ffmpeg -i input.mp4 \
  -vf "hue=h=t*36" \
  output.mp4  # Full rotation every 10 seconds

eq Filter (Comprehensive)

bash
# Full color adjustment
ffmpeg -i input.mp4 \
  -vf "eq=contrast=1.1:brightness=0.05:saturation=1.2:gamma=1.1" \
  output.mp4

# eq parameters:
# contrast: 0-2 (default 1)
# brightness: -1 to 1 (default 0)
# saturation: 0-3 (default 1)
# gamma: 0.1-10 (default 1)
# gamma_r/gamma_g/gamma_b: per-channel gamma

White Balance

colortemperature Filter (FFmpeg 5.1+)

bash
# Warm up (lower temperature)
ffmpeg -i input.mp4 \
  -vf "colortemperature=temperature=5000" \
  output.mp4

# Cool down (higher temperature)
ffmpeg -i input.mp4 \
  -vf "colortemperature=temperature=8000" \
  output.mp4

# Neutral daylight
ffmpeg -i input.mp4 \
  -vf "colortemperature=temperature=6500" \
  output.mp4

Manual White Balance

bash
# Using colorbalance for white balance
# Correct blue cast (add warmth)
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=0.1:rm=0.05:bs=-0.1:bm=-0.05" \
  output.mp4

# Correct yellow/orange cast (add blue)
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs=-0.1:rm=-0.05:bs=0.1:bm=0.05" \
  output.mp4

Color Space Conversions

SDR Color Spaces

bash
# Convert BT.601 to BT.709
ffmpeg -i input.mp4 \
  -vf "colorspace=bt709:iall=bt601-6-625:fast=1" \
  -c:v libx264 -crf 18 \
  output.mp4

# Force color space metadata
ffmpeg -i input.mp4 \
  -color_primaries bt709 -color_trc bt709 -colorspace bt709 \
  -c:v libx264 -crf 18 output.mp4

HDR to SDR Tone Mapping

bash
# Basic HDR to SDR (BT.2020/PQ to BT.709)
ffmpeg -i hdr_input.mp4 \
  -vf "zscale=t=linear:npl=100,format=gbrpf32le,\
       zscale=p=bt709,tonemap=tonemap=hable:desat=0,\
       zscale=t=bt709:m=bt709:r=tv,format=yuv420p" \
  -c:v libx264 -crf 18 sdr_output.mp4

# HDR10 to SDR with better quality
ffmpeg -i hdr10_input.mp4 \
  -vf "zscale=t=linear:npl=100,format=gbrpf32le,\
       zscale=p=bt709,tonemap=tonemap=reinhard:param=0.4:desat=0,\
       zscale=t=bt709:m=bt709,format=yuv420p" \
  -c:v libx264 -crf 18 output.mp4

Tone Mapping Algorithms

Algorithm Characteristic
none Clipping only
clip Hard clip to SDR range
linear Linear scale
gamma Gamma curve
reinhard Soft rolloff, natural
hable Film-like, John Hable
mobius S-curve, smooth

Selective Color Manipulation

Color Isolation (Selective Desaturation)

bash
# Keep only red, desaturate rest (Sin City effect)
ffmpeg -i input.mp4 \
  -vf "hue=s=0,\
       split[a][b];\
       [a]hue=s=0[bw];\
       [b]colorkey=0xFF0000:0.3:0.1[red];\
       [bw][red]overlay" \
  output.mp4

# Isolate specific color range using selectivecolor
# Note: Use colorchannelmixer for more control

colorchannelmixer

bash
# Convert to grayscale with proper luminance weights
ffmpeg -i input.mp4 \
  -vf "colorchannelmixer=.3:.59:.11:0:.3:.59:.11:0:.3:.59:.11" \
  output.mp4

# Sepia tone
ffmpeg -i input.mp4 \
  -vf "colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131" \
  output.mp4

# Swap red and blue channels
ffmpeg -i input.mp4 \
  -vf "colorchannelmixer=0:0:1:0:0:1:0:0:1:0:0:0" \
  output.mp4

# Boost reds, reduce blues
ffmpeg -i input.mp4 \
  -vf "colorchannelmixer=1.2:0:0:0:0:1:0:0:0:0:0.8:0" \
  output.mp4

Professional Grading Chains

Film Emulation

bash
# 35mm Film Look
ffmpeg -i input.mp4 \
  -vf "\
    eq=contrast=1.1:saturation=0.95:gamma=1.05,\
    curves=preset=cross_process,\
    colorbalance=rs=0.05:bh=-0.05,\
    noise=c0s=3:c1s=3:c0f=t:c1f=t,\
    unsharp=3:3:0.5" \
  -c:v libx264 -crf 18 film_look.mp4

# Kodak Portra Style
ffmpeg -i input.mp4 \
  -vf "\
    eq=saturation=0.9:contrast=1.05,\
    colorbalance=rs=0.1:gs=-0.02:rm=0.05:gm=-0.02,\
    curves=r='0/0.02 1/0.98':g='0/0 1/1':b='0/0.02 1/0.95'" \
  output.mp4

# Fuji Film Style
ffmpeg -i input.mp4 \
  -vf "\
    eq=saturation=1.1:contrast=1.05,\
    colorbalance=gs=0.05:bs=0.08:gm=0.02:bm=0.05,\
    curves=g='0/0.02 1/1'" \
  output.mp4

Modern Cinematic

bash
# Blockbuster Orange & Teal
ffmpeg -i input.mp4 \
  -vf "\
    eq=contrast=1.15:saturation=1.1:brightness=-0.02,\
    colorbalance=rs=0.12:gs=-0.04:bs=-0.15:rh=0.08:bh=-0.12,\
    curves=all='0/0.02 0.5/0.5 1/0.98',\
    unsharp=5:5:0.6" \
  -c:v libx264 -crf 18 cinematic.mp4

# Moody/Dark Cinematic
ffmpeg -i input.mp4 \
  -vf "\
    eq=contrast=1.2:brightness=-0.08:saturation=0.85,\
    colorbalance=bs=0.1:bm=0.05:gh=-0.05,\
    curves=all='0/0.05 0.5/0.45 1/0.9'" \
  output.mp4

# High Key Bright
ffmpeg -i input.mp4 \
  -vf "\
    eq=contrast=0.9:brightness=0.1:saturation=0.9:gamma=0.85,\
    colorbalance=rs=0.05:gs=0.02:bs=0.02" \
  output.mp4

Music Video Styles

bash
# Neon/Cyberpunk
ffmpeg -i input.mp4 \
  -vf "\
    eq=contrast=1.3:saturation=1.5:brightness=-0.05,\
    colorbalance=rs=0.2:bs=0.2:rm=-0.1:bm=0.15,\
    unsharp=5:5:1.0" \
  output.mp4

# VHS/Retro
ffmpeg -i input.mp4 \
  -vf "\
    eq=saturation=1.2:contrast=0.95,\
    chromashift=cbh=2:cbv=2,\
    noise=c0s=10:c1s=5:allf=t,\
    curves=preset=vintage" \
  output.mp4

# Dream/Ethereal
ffmpeg -i input.mp4 \
  -filter_complex "\
    [0:v]split[a][b];\
    [a]gblur=sigma=15,eq=brightness=0.1[blur];\
    [b][blur]blend=all_mode=screen:all_opacity=0.3[out]" \
  -map "[out]" -c:v libx264 -crf 18 dream.mp4

Animated Color Effects

Time-Based Color Changes

bash
# Gradually warm over time
ffmpeg -i input.mp4 \
  -vf "colorbalance=rs='0.1*t/30':bs='-0.1*t/30'" \
  output.mp4

# Pulsing saturation
ffmpeg -i input.mp4 \
  -vf "hue=s='1+0.3*sin(t*2)'" \
  output.mp4

# Day to night transition
ffmpeg -i input.mp4 \
  -vf "\
    colortemperature=temperature='8000-3000*t/30',\
    eq=brightness='-0.2*t/30':saturation='1-0.3*t/30'" \
  output.mp4

Troubleshooting

Common Issues

Banding in gradients after grading:

bash
# Add dithering
ffmpeg -i input.mp4 \
  -vf "lut3d=lut.cube,format=yuv420p10le" \
  -c:v libx264 -profile:v high10 -crf 18 output.mp4

# Or add subtle noise
ffmpeg -i input.mp4 \
  -vf "lut3d=lut.cube,noise=c0s=2:c0f=a" \
  output.mp4

Color shift after encoding:

bash
# Force color space flags
ffmpeg -i input.mp4 \
  -vf "your_filters" \
  -color_primaries bt709 -color_trc bt709 -colorspace bt709 \
  -c:v libx264 -crf 18 output.mp4

Chromakey green fringe:

bash
# Use despill with colorbalance
ffmpeg -i green_screen.mp4 -i bg.mp4 \
  -filter_complex "\
    [0:v]chromakey=0x00FF00:0.25:0.1,\
    colorbalance=gs=-0.15:gm=-0.1[fg];\
    [1:v][fg]overlay" \
  output.mp4

This guide covers FFmpeg color grading and chromakey operations. For transitions see ffmpeg-transitions-effects, for shapes see ffmpeg-shapes-graphics.

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