media-processing by mrgoonie

---
name: media-processing
description: Process multimedia files with FFmpeg (video/audio encoding, conversion, streaming, filtering, hardware acceleration) and ImageMagick (image manipulation, format conversion, batch processing, effects, composition). Use when converting media formats, encoding videos with specific codecs (H.264, H.265, VP9), resizing/cropping images, extracting audio from video, applying filters and effects, optimizing file sizes, creating streaming manifests (HLS/DASH), generating thumbnails, batch processing images, creating composite images, or implementing media processing pipelines. Supports 100+ formats, hardware acceleration (NVENC, QSV), and complex filtergraphs.
license: MIT
---

# Media Processing Skill

Process video, audio, and images using FFmpeg and ImageMagick command-line tools for conversion, optimization, streaming, and manipulation tasks.

## When to Use This Skill

Use when:
- Converting media formats (video, audio, images)
- Encoding video with codecs (H.264, H.265, VP9, AV1)
- Processing images (resize, crop, effects, watermarks)
- Extracting audio from video
- Creating streaming manifests (HLS/DASH)
- Generating thumbnails and previews
- Batch processing media files
- Optimizing file sizes and quality
- Applying filters and effects
- Creating composite images or videos

## Tool Selection Guide

### FFmpeg: Video/Audio Processing
Use FFmpeg for:
- Video encoding, conversion, transcoding
- Audio extraction, conversion, mixing
- Live streaming (RTMP, HLS, DASH)
- Video filters (scale, crop, rotate, overlay)
- Hardware-accelerated encoding
- Media file inspection (ffprobe)
- Frame extraction, concatenation
- Codec selection and optimization

### ImageMagick: Image Processing
Use ImageMagick for:
- Image format conversion (PNG, JPEG, WebP, GIF)
- Resizing, cropping, transformations
- Batch image processing (mogrify)
- Visual effects (blur, sharpen, sepia)
- Text overlays and watermarks
- Image composition and montages
- Color adjustments, filters
- Thumbnail generation

### Decision Matrix

| Task | Tool | Why |
|------|------|-----|
| Video encoding | FFmpeg | Native video codec support |
| Audio extraction | FFmpeg | Direct stream manipulation |
| Image resize | ImageMagick | Optimized for still images |
| Batch images | ImageMagick | mogrify for in-place edits |
| Video thumbnails | FFmpeg | Frame extraction built-in |
| GIF creation | FFmpeg or ImageMagick | FFmpeg for video source, ImageMagick for images |
| Streaming | FFmpeg | Live streaming protocols |
| Image effects | ImageMagick | Rich filter library |

## Installation

### macOS
```bash
brew install ffmpeg imagemagick
```

### Ubuntu/Debian
```bash
sudo apt-get install ffmpeg imagemagick
```

### Windows
```bash
# Using winget
winget install ffmpeg
winget install ImageMagick.ImageMagick

# Or download binaries
# FFmpeg: https://ffmpeg.org/download.html
# ImageMagick: https://imagemagick.org/script/download.php
```

### Verify Installation
```bash
ffmpeg -version
ffprobe -version
magick -version
# or
convert -version
```

## Quick Start Examples

### Video Conversion
```bash
# Convert format (copy streams, fast)
ffmpeg -i input.mkv -c copy output.mp4

# Re-encode with H.264
ffmpeg -i input.avi -c:v libx264 -crf 22 -c:a aac output.mp4

# Resize video to 720p
ffmpeg -i input.mp4 -vf scale=-1:720 -c:a copy output.mp4
```

### Audio Extraction
```bash
# Extract audio (no re-encoding)
ffmpeg -i video.mp4 -vn -c:a copy audio.m4a

# Convert to MP3
ffmpeg -i video.mp4 -vn -q:a 0 audio.mp3
```

### Image Processing
```bash
# Convert format
magick input.png output.jpg

# Resize maintaining aspect ratio
magick input.jpg -resize 800x600 output.jpg

# Create square thumbnail
magick input.jpg -resize 200x200^ -gravity center -extent 200x200 thumb.jpg
```

### Batch Image Resize
```bash
# Resize all JPEGs to 800px width
mogrify -resize 800x -quality 85 *.jpg

# Output to separate directory
mogrify -path ./output -resize 800x600 *.jpg
```

### Video Thumbnail
```bash
# Extract frame at 5 seconds
ffmpeg -ss 00:00:05 -i video.mp4 -vframes 1 -vf scale=320:-1 thumb.jpg
```

### HLS Streaming
```bash
# Generate HLS playlist
ffmpeg -i input.mp4 \
  -c:v libx264 -preset fast -crf 22 -g 48 \
  -c:a aac -b:a 128k \
  -f hls -hls_time 6 -hls_playlist_type vod \
  playlist.m3u8
```

### Image Watermark
```bash
# Add watermark to corner
magick input.jpg watermark.png -gravity southeast \
  -geometry +10+10 -composite output.jpg
```

## Common Workflows

### Optimize Video for Web
```bash
# H.264 with good compression
ffmpeg -i input.mp4 \
  -c:v libx264 -preset slow -crf 23 \
  -c:a aac -b:a 128k \
  -movflags +faststart \
  output.mp4
```

### Create Responsive Images
```bash
# Generate multiple sizes
for size in 320 640 1024 1920; do
  magick input.jpg -resize ${size}x -quality 85 "output-${size}w.jpg"
done
```

### Extract Video Segment
```bash
# From 1:30 to 3:00 (re-encode for precision)
ffmpeg -i input.mp4 -ss 00:01:30 -to 00:03:00 \
  -c:v libx264 -c:a aac output.mp4
```

### Batch Image Optimization
```bash
# Convert PNG to optimized JPEG
mogrify -path ./optimized -format jpg -quality 85 -strip *.png
```

### Video GIF Creation
```bash
# High quality GIF with palette
ffmpeg -i input.mp4 -vf "fps=15,scale=640:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" output.gif
```

### Image Blur Effect
```bash
# Gaussian blur
magick input.jpg -gaussian-blur 0x8 output.jpg
```

## Advanced Techniques

### Multi-Pass Video Encoding
```bash
# Pass 1 (analysis)
ffmpeg -y -i input.mkv -c:v libx264 -b:v 2600k -pass 1 -an -f null /dev/null

# Pass 2 (encoding)
ffmpeg -i input.mkv -c:v libx264 -b:v 2600k -pass 2 -c:a aac output.mp4
```

### Hardware-Accelerated Encoding
```bash
# NVIDIA NVENC
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc -preset fast -crf 22 output.mp4

# Intel QuickSync
ffmpeg -hwaccel qsv -c:v h264_qsv -i input.mp4 -c:v h264_qsv output.mp4
```

### Complex Image Pipeline
```bash
# Resize, crop, border, adjust
magick input.jpg \
  -resize 1000x1000^ \
  -gravity center \
  -crop 1000x1000+0+0 +repage \
  -bordercolor black -border 5x5 \
  -brightness-contrast 5x10 \
  -quality 90 \
  output.jpg
```

### Video Filter Chains
```bash
# Scale, denoise, watermark
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex "[0:v]scale=1280:720,hqdn3d[v];[v][1:v]overlay=10:10" \
  -c:a copy output.mp4
```

### Animated GIF from Images
```bash
# Create with delay
magick -delay 100 -loop 0 frame*.png animated.gif

# Optimize size
magick animated.gif -fuzz 5% -layers Optimize optimized.gif
```

## Media Analysis

### Inspect Video Properties
```bash
# Detailed JSON output
ffprobe -v quiet -print_format json -show_format -show_streams input.mp4

# Get resolution
ffprobe -v error -select_streams v:0 \
  -show_entries stream=width,height \
  -of csv=s=x:p=0 input.mp4
```

### Image Information
```bash
# Basic info
identify image.jpg

# Detailed format
identify -verbose image.jpg

# Custom format
identify -format "%f: %wx%h %b\n" image.jpg
```

## Performance Tips

1. **Use CRF for quality control** - Better than bitrate for video
2. **Copy streams when possible** - Avoid re-encoding with `-c copy`
3. **Hardware acceleration** - GPU encoding 5-10x faster
4. **Appropriate presets** - Balance speed vs compression
5. **Batch with mogrify** - In-place image processing
6. **Strip metadata** - Reduce file size with `-strip`
7. **Progressive JPEG** - Better web loading with `-interlace Plane`
8. **Limit memory** - Prevent crashes on large batches
9. **Test on samples** - Verify settings before batch
10. **Parallel processing** - Use GNU Parallel for multiple files

## Reference Documentation

Detailed guides in `references/`:

- **ffmpeg-encoding.md** - Video/audio codecs, quality optimization, hardware acceleration
- **ffmpeg-streaming.md** - HLS/DASH, live streaming, adaptive bitrate
- **ffmpeg-filters.md** - Video/audio filters, complex filtergraphs
- **imagemagick-editing.md** - Format conversion, effects, transformations
- **imagemagick-batch.md** - Batch processing, mogrify, parallel operations
- **format-compatibility.md** - Format support, codec recommendations

## Common Parameters

### FFmpeg Video
- `-c:v` - Video codec (libx264, libx265, libvpx-vp9)
- `-crf` - Quality (0-51, lower=better, 23=default)
- `-preset` - Speed/compression (ultrafast to veryslow)
- `-b:v` - Video bitrate (e.g., 2M, 2500k)
- `-vf` - Video filters

### FFmpeg Audio
- `-c:a` - Audio codec (aac, mp3, opus)
- `-b:a` - Audio bitrate (e.g., 128k, 192k)
- `-ar` - Sample rate (44100, 48000)

### ImageMagick Geometry
- `800x600` - Fit within (maintains aspect)
- `800x600!` - Force exact size
- `800x600^` - Fill (may crop)
- `800x` - Width only
- `x600` - Height only
- `50%` - Scale percentage

## Troubleshooting

**FFmpeg "Unknown encoder"**
```bash
# Check available encoders
ffmpeg -encoders | grep h264

# Install codec libraries
sudo apt-get install libx264-dev libx265-dev
```

**ImageMagick "not authorized"**
```bash
# Edit policy file
sudo nano /etc/ImageMagick-7/policy.xml
# Change <policy domain="coder" rights="none" pattern="PDF" />
# to <policy domain="coder" rights="read|write" pattern="PDF" />
```

**Memory errors**
```bash
# Limit memory usage
ffmpeg -threads 4 input.mp4 output.mp4
magick -limit memory 2GB -limit map 4GB input.jpg output.jpg
```

## Resources

- FFmpeg: https://ffmpeg.org/documentation.html
- FFmpeg Wiki: https://trac.ffmpeg.org/
- ImageMagick: https://imagemagick.org/
- ImageMagick Usage: https://imagemagick.org/Usage/