open-agent-library/skill/video-editing/references/ffmpeg-codecs.md

FFmpeg Codecs Reference

This document provides detailed information about video and audio codecs available in ffmpeg.

Video Codecs

H.264 (libx264) - Most Compatible

The most widely supported video codec. Works on virtually all devices and platforms.

# Basic encoding
ffmpeg -i input.mp4 -c:v libx264 -crf 23 output.mp4

# High quality
ffmpeg -i input.mp4 -c:v libx264 -crf 18 -preset slow output.mp4

# Fast encoding
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset fast output.mp4

# Web compatible (baseline profile)
ffmpeg -i input.mp4 -c:v libx264 -profile:v baseline -level 3.0 -pix_fmt yuv420p output.mp4

# High profile for best quality
ffmpeg -i input.mp4 -c:v libx264 -profile:v high -level 4.1 output.mp4

Presets (speed vs compression):

• ultrafast - Fastest encoding, largest file
• superfast
• veryfast
• faster
• fast
• medium - Default
• slow
• slower
• veryslow - Best compression, slowest

CRF Values (quality):

• 0 = Lossless
• 18 = Visually lossless
• 23 = Default
• 28 = Smaller file
• 51 = Worst quality

Profiles:

• baseline - Most compatible, no B-frames
• main - Good balance
• high - Best quality

H.265/HEVC (libx265) - Better Compression

50% smaller files than H.264 at same quality. Requires more processing power.

# Basic encoding
ffmpeg -i input.mp4 -c:v libx265 -crf 28 output.mp4

# High quality
ffmpeg -i input.mp4 -c:v libx265 -crf 22 -preset slow output.mp4

# 10-bit encoding (HDR support)
ffmpeg -i input.mp4 -c:v libx265 -crf 22 -pix_fmt yuv420p10le output.mp4

Note: CRF values differ from x264. Add ~6 to get equivalent quality (x264 CRF 23 ≈ x265 CRF 28).

VP9 (libvpx-vp9) - WebM Format

Open source codec used by YouTube. Good for web streaming.

# Basic encoding
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 output.webm

# Two-pass encoding (recommended)
ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 2M -pass 1 -an -f null /dev/null && \
ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 2M -pass 2 -c:a libopus output.webm

# High quality
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 20 -b:v 0 -deadline good -cpu-used 2 output.webm

AV1 (libaom-av1, libsvtav1) - Best Compression

Newest codec with best compression. Slow to encode.

# Using libaom-av1 (slow but high quality)
ffmpeg -i input.mp4 -c:v libaom-av1 -crf 30 -cpu-used 4 output.mp4

# Using SVT-AV1 (faster)
ffmpeg -i input.mp4 -c:v libsvtav1 -crf 30 -preset 6 output.mp4

# Using rav1e
ffmpeg -i input.mp4 -c:v librav1e -crf 30 output.mp4

ProRes (prores_ks) - Professional Editing

Lossless/near-lossless codec for editing. Large files.

# ProRes 422 (standard)
ffmpeg -i input.mp4 -c:v prores_ks -profile:v 2 output.mov

# ProRes 422 HQ (high quality)
ffmpeg -i input.mp4 -c:v prores_ks -profile:v 3 output.mov

# ProRes 4444 (with alpha channel)
ffmpeg -i input.mp4 -c:v prores_ks -profile:v 4 -pix_fmt yuva444p10le output.mov

Profiles:

• 0 = ProRes 422 Proxy
• 1 = ProRes 422 LT
• 2 = ProRes 422
• 3 = ProRes 422 HQ
• 4 = ProRes 4444
• 5 = ProRes 4444 XQ

DNxHD/DNxHR - Avid Professional

# DNxHD for 1080p
ffmpeg -i input.mp4 -c:v dnxhd -profile:v dnxhr_hq output.mov

# DNxHR for higher resolutions
ffmpeg -i input.mp4 -c:v dnxhd -profile:v dnxhr_hqx output.mov

Hardware Accelerated Encoding

macOS VideoToolbox (H.264/HEVC)

# H.264
ffmpeg -i input.mp4 -c:v h264_videotoolbox -b:v 5M output.mp4

# HEVC
ffmpeg -i input.mp4 -c:v hevc_videotoolbox -b:v 5M output.mp4

NVIDIA NVENC

# H.264
ffmpeg -i input.mp4 -c:v h264_nvenc -preset p4 -cq 23 output.mp4

# HEVC
ffmpeg -i input.mp4 -c:v hevc_nvenc -preset p4 -cq 28 output.mp4

Intel QuickSync

# H.264
ffmpeg -i input.mp4 -c:v h264_qsv -global_quality 23 output.mp4

# HEVC
ffmpeg -i input.mp4 -c:v hevc_qsv -global_quality 28 output.mp4

Audio Codecs

AAC - Most Compatible

# Default AAC
ffmpeg -i input.mp4 -c:a aac -b:a 128k output.mp4

# High quality
ffmpeg -i input.mp4 -c:a aac -b:a 256k output.mp4

# Variable bitrate
ffmpeg -i input.mp4 -c:a aac -q:a 2 output.mp4

MP3 (libmp3lame)

# Constant bitrate
ffmpeg -i input.wav -c:a libmp3lame -b:a 320k output.mp3

# Variable bitrate (quality 0-9, lower is better)
ffmpeg -i input.wav -c:a libmp3lame -q:a 2 output.mp3

VBR Quality:

• 0 = ~245 kbps
• 2 = ~190 kbps
• 4 = ~165 kbps
• 6 = ~130 kbps

Opus (libopus) - Best Quality

Modern codec, best quality at low bitrates.

# VoIP quality
ffmpeg -i input.wav -c:a libopus -b:a 64k output.opus

# Music quality
ffmpeg -i input.wav -c:a libopus -b:a 128k output.opus

# High quality
ffmpeg -i input.wav -c:a libopus -b:a 256k output.opus

Vorbis (libvorbis) - OGG Format

ffmpeg -i input.wav -c:a libvorbis -q:a 5 output.ogg

FLAC - Lossless

# Standard compression
ffmpeg -i input.wav -c:a flac output.flac

# Maximum compression
ffmpeg -i input.wav -c:a flac -compression_level 12 output.flac

WAV/PCM - Uncompressed

# 16-bit PCM
ffmpeg -i input.mp3 -c:a pcm_s16le output.wav

# 24-bit PCM
ffmpeg -i input.mp3 -c:a pcm_s24le output.wav

# 32-bit float
ffmpeg -i input.mp3 -c:a pcm_f32le output.wav

Container Formats

MP4 (.mp4)

• Video: H.264, H.265, AV1
• Audio: AAC, MP3, AC3
• Most compatible format

# Enable fast start for streaming
ffmpeg -i input.mp4 -c copy -movflags +faststart output.mp4

MKV (.mkv)

• Supports almost all codecs
• Great for archiving
• Less device compatibility

WebM (.webm)

• Video: VP8, VP9, AV1
• Audio: Vorbis, Opus
• Web-optimized

MOV (.mov)

• Apple's container format
• Video: H.264, ProRes, HEVC
• Audio: AAC, ALAC

AVI (.avi)

• Legacy format
• Limited codec support
• Not recommended for new content

Codec Comparison Table

Codec	Quality	File Size	Encode Speed	Compatibility
H.264	Good	Medium	Fast	Excellent
H.265	Better	Small	Slow	Good
VP9	Better	Small	Slow	Web only
AV1	Best	Smallest	Very slow	Growing
ProRes	Excellent	Very large	Fast	Apple/Pro

Choosing the Right Codec

For Social Media/Web

# H.264 with fast start (most compatible)
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -c:a aac -b:a 128k -movflags +faststart output.mp4

For Archiving

# H.265 for smaller files
ffmpeg -i input.mp4 -c:v libx265 -crf 22 -preset slow -c:a flac output.mkv

For Editing/Post-Production

# ProRes for quality
ffmpeg -i input.mp4 -c:v prores_ks -profile:v 3 -c:a pcm_s16le output.mov

For Streaming

# HLS with multiple bitrates
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -c:a aac -f hls -hls_time 10 -hls_list_size 0 output.m3u8

For Smallest File Size

# AV1 (if time permits)
ffmpeg -i input.mp4 -c:v libsvtav1 -crf 35 -preset 4 -c:a libopus -b:a 96k output.mp4