FFmpeg Fundamentals (2025)

Foundational FFmpeg knowledge for 7.1 LTS and 8.0.1. This SKILL is a lean orchestrator; detailed recipes and tables live under references/.

When to Use This Skill

Use for foundational FFmpeg operations:

• First-time FFmpeg users needing syntax help
• Basic transcoding between formats (MP4, WebM, MKV, MOV)
• Understanding codec options and quality settings
• Simple filter operations (scale, crop, rotate)
• File analysis with ffprobe

For specialized topics see related skills: hardware encoding -> ffmpeg-hardware-acceleration, streaming -> ffmpeg-streaming, Docker -> ffmpeg-docker-containers, advanced filter graphs -> ffmpeg-filter-complex-patterns.

Quick Reference

Core Workflow

1. Verify your FFmpeg version with ffmpeg -version. Prefer the latest stable (8.0.1) or the 7.1 LTS.
2. Probe the input with ffprobe to inspect codecs, container, resolution, and duration.
3. Decide whether to remux (-c copy) or transcode (specify encoders, quality).
4. Pick encoders and quality settings (see Codec Reference below).
5. Add filters as needed (see references/filter-essentials.md and references/frame-manipulation.md).
6. Verify the output: re-probe, check duration, A/V sync, and pixel format.

Basic Command Syntax

ffmpeg [global_options] {[input_options] -i input} ... {[output_options] output} ...

Common examples:

# Basic transcode
ffmpeg -i input.mp4 output.mkv

# Specify codecs
ffmpeg -i input.mp4 -c:v libx264 -c:a aac output.mp4

# Copy streams without re-encoding (remux)
ffmpeg -i input.mkv -c copy output.mp4

# CRF quality mode
ffmpeg -i input.mp4 -c:v libx264 -crf 23 output.mp4

# Bitrate mode
ffmpeg -i input.mp4 -c:v libx264 -b:v 5M output.mp4

# Overwrite without prompting
ffmpeg -y -i input.mp4 output.mp4

# Show progress as parseable stats
ffmpeg -progress - -i input.mp4 output.mp4

For exhaustive option ordering rules, stream specifiers, and per-format option tables, see the ffmpeg-command-syntax skill.

Codec Reference (2025)

Video Codecs (Software)

Hardware Encoders

Hardware Decoders (FFmpeg 8.0+)

Audio Codecs

Probing & Analysis

# Get media info as JSON
ffprobe -v quiet -print_format json -show_format -show_streams input.mp4

# Get duration
ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 input.mp4

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

# Get codec
ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 input.mp4

# Validate file
ffprobe -v error input.mp4 && echo "Valid" || echo "Invalid"

Best Practices

Performance

1. Use -threads 0 to auto-detect optimal thread count.
2. Place -ss before -i for fast seeking (may be less accurate); after -i for frame-accurate seek.
3. Use -c copy when possible to avoid re-encoding.
4. Use hardware acceleration when available.

Quality

1. Prefer CRF over bitrate for single-pass encoding.
2. Use -preset slow or slower for better compression.
3. Use -tune options (film, animation, grain) when appropriate.
4. Keep -pix_fmt yuv420p for broad compatibility.

Compatibility

1. Use -movflags +faststart for web MP4 files.
2. Use -vtag hvc1 for HEVC on Apple devices.
3. Test on target devices before mass conversion.
4. Provide fallback formats for older browsers.

Error Prevention

1. Test commands on a sample file first.
2. Use -report for detailed logging.
3. Check output file size and duration.
4. Verify A/V sync after conversion.

Capability Discovery

ffmpeg -encoders          # List encoders
ffmpeg -decoders          # List decoders
ffmpeg -formats           # List formats
ffmpeg -filters           # List filters
ffmpeg -hwaccels          # List hardware acceleration methods
ffmpeg -h encoder=libx264 # Encoder-specific options

Exit codes:

• 0: success
• 1: error (check stderr)
• 255: interrupted (Ctrl+C)

Reference Map

Detailed recipes, option tables, and FFmpeg 8.0-specific guides:

• references/version-history.md - Full FFmpeg 8.0 / 7.1 LTS feature lists, update strategy, official resources
• references/common-operations.md - Format conversion, scaling, trimming, concat, audio, subtitles, Whisper recipe, image ops, output optimization (web/iOS/Android)
• references/filter-essentials.md - Video filters (-vf), audio filters (-af), complex filtergraphs, filter_complex syntax reference
• references/frame-manipulation.md - Frame rate, setpts, select, thumbnails, tiles, freezing, looping, reversing
• references/whisper-transcription.md - Whisper AI filter for speech recognition and subtitle generation
• references/vvc-h266-encoding.md - VVC/H.266 encoding with libvvenc plus hardware decode
• references/vulkan-compute-codecs.md - Vulkan compute-based codecs (FFv1, AV1, VP9, ProRes RAW)

For deeper dives: ffmpeg-filter-complex-patterns, ffmpeg-hardware-acceleration, ffmpeg-streaming, ffmpeg-captions-subtitles, ffmpeg-audio-processing.