ffmpeg Skill

Comprehensive multimedia framework for video/audio encoding, conversion, streaming, and filtering.

When to Use

Use ffmpeg when you need:

Convert video formats
Compress videos
Extract audio
Create streams
Apply filters
Batch process media
Generate thumbnails

Quick Start

Invoke the Skill

"Use ffmpeg to:
- Convert video.mkv to MP4
- Compress to 720p
- Reduce file size
- Maintain good quality"

What You Get

The skill will help you:

Choose right codecs
Set optimal quality
Apply filters
Optimize file size
Handle batch processing

Common Use Cases

Format Conversion

"Use ffmpeg to convert all MKV files to MP4 with H.264 codec"

Video Compression

"Use ffmpeg to compress 4K video to 1080p with good quality"

Extract Audio

"Use ffmpeg to extract audio from video as MP3"

Create GIF

"Use ffmpeg to create high-quality GIF from video clip"

Popular Operations

Convert Format

# Simple conversion
ffmpeg -i input.mkv -c copy output.mp4

# With re-encoding
ffmpeg -i input.avi -c:v libx264 -c:a aac output.mp4

Compress Video

# Quality-based (CRF 23 = default, lower = better)
ffmpeg -i input.mp4 -c:v libx264 -crf 22 -preset slow output.mp4

# Target file size with two-pass
ffmpeg -i input.mp4 -c:v libx264 -b:v 2M -pass 1 -f null /dev/null
ffmpeg -i input.mp4 -c:v libx264 -b:v 2M -pass 2 output.mp4

Extract Audio

# Keep original format
ffmpeg -i video.mp4 -vn -c:a copy audio.m4a

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

Trim Video

# Without re-encoding (fast)
ffmpeg -i input.mp4 -ss 00:01:00 -to 00:02:00 -c copy output.mp4

# With re-encoding (precise)
ffmpeg -i input.mp4 -ss 00:01:00 -t 00:01:00 -c:v libx264 output.mp4

Common Codecs

Video Codecs

H.264 (libx264): Universal compatibility
H.265 (libx265): Better compression, 4K
VP9: Open-source, YouTube
AV1: Next-gen, best compression

Audio Codecs

AAC: Industry standard
MP3: Universal compatibility
Opus: Best for streaming/voice
FLAC: Lossless quality

Video Filters

Scale/Resize

# Specific dimensions
ffmpeg -i input.mp4 -vf scale=1280:720 output.mp4

# Keep aspect ratio
ffmpeg -i input.mp4 -vf scale=1280:-1 output.mp4

# Half resolution
ffmpeg -i input.mp4 -vf scale=iw/2:ih/2 output.mp4

Crop

# Manual crop
ffmpeg -i input.mp4 -vf "crop=1280:720:0:0" output.mp4

# Auto-detect black borders
ffmpeg -i input.mp4 -vf cropdetect output.mp4

Other Filters

# Denoise
ffmpeg -i input.mp4 -vf hqdn3d output.mp4

# Rotate 90° clockwise
ffmpeg -i input.mp4 -vf "transpose=1" output.mp4

# Add watermark
ffmpeg -i video.mp4 -i logo.png -filter_complex "overlay=10:10" output.mp4

Audio Filters

# Increase volume
ffmpeg -i input.mp4 -af "volume=10dB" output.mp4

# Normalize audio
ffmpeg -i input.mp4 -af loudnorm output.mp4

# Mix audio tracks
ffmpeg -i audio1.mp3 -i audio2.mp3 -filter_complex amix output.mp3

Streaming

RTMP (Twitch/YouTube)

ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset veryfast -maxrate 3000k \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.twitch.tv/app/YOUR_KEY

HLS Streaming

ffmpeg -i input.mp4 \
  -c:v libx264 -c:a aac \
  -f hls -hls_time 6 -hls_playlist_type vod \
  playlist.m3u8

Advanced Use Cases

Create GIF

ffmpeg -i input.mp4 \
  -vf "fps=15,scale=640:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" \
  output.gif

Extract Frames

# All frames
ffmpeg -i input.mp4 frame_%04d.png

# 1 frame per second
ffmpeg -i input.mp4 -vf fps=1 frame_%04d.png

# Single frame at 5s
ffmpeg -ss 00:00:05 -i input.mp4 -frames:v 1 frame.png

Video from Images

ffmpeg -framerate 30 -i frame_%04d.png \
  -c:v libx264 -pix_fmt yuv420p output.mp4

Concatenate Videos

Create concat.txt:

file 'input1.mp4'
file 'input2.mp4'

Run:

ffmpeg -f concat -safe 0 -i concat.txt -c copy output.mp4

Batch Processing

Convert All Files

for file in *.mkv; do
  ffmpeg -i "$file" -c:v libx264 -crf 22 "${file%.mkv}.mp4"
done

Resize All Videos

for file in *.mp4; do
  ffmpeg -i "$file" -vf scale=-1:720 "720p_${file}"
done

Hardware Acceleration

NVIDIA GPU

ffmpeg -hwaccel cuda -i input.mp4 \
  -c:v h264_nvenc -preset fast output.mp4

Intel QuickSync

ffmpeg -hwaccel qsv -i input.mp4 \
  -c:v h264_qsv -preset fast output.mp4

Quality Settings

CRF Values

0 = Lossless (huge file)
17-18 = Visually lossless
20-23 = High quality (recommended)
24-28 = Medium quality
30+ = Low quality

Presets (speed vs compression)

ultrafast, superfast, veryfast, faster, fast
medium (default)
slow, slower, veryslow

Quick Examples

Simple Conversion:

"Use ffmpeg to convert video.mkv to MP4"

Compress for Web:

"Use ffmpeg to compress video for web:
- 1080p resolution
- Good quality
- Small file size
- H.264 codec"

Extract Audio:

"Use ffmpeg to extract audio from all videos in folder as MP3"

Create Thumbnail:

"Use ffmpeg to create thumbnail from video at 5 second mark"

Best Practices

Test on short clip first
Use CRF for quality
Copy streams when possible (-c copy)
Choose appropriate presets
Don’t upscale unnecessarily
Match audio quality to video
Use hardware acceleration
Verify output quality

Troubleshooting

Unknown encoder

# Check available encoders
ffmpeg -encoders | grep h264

Compatibility issues

Use safe defaults:

ffmpeg -i input.mkv -c:v libx264 -profile:v high \
  -pix_fmt yuv420p -c:a aac output.mp4

Performance issues

Use hardware acceleration
Choose faster presets
Reduce resolution
Enable multi-threading

Next Steps

Bottom Line: ffmpeg handles all video/audio needs. Convert, compress, stream - one tool for everything.