FFmpeg for Video Production

FFmpeg is the essential tool for video/audio processing. This skill covers common operations for Remotion video projects.

Quick Reference

GIF to MP4 (Remotion-compatible)

ffmpeg -i input.gif -movflags faststart -pix_fmt yuv420p
-vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" output.mp4

Why these flags:

• -movflags faststart

• Moves metadata to start for web streaming

• -pix_fmt yuv420p

• Ensures compatibility with most players

• scale=trunc(...)

• Forces even dimensions (required by most codecs)

Resize Video

To 1920x1080 (maintain aspect ratio, add black bars)

ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2" output.mp4

To 1920x1080 (crop to fill)

ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=increase,crop=1920:1080" output.mp4

Scale to width, auto height

ffmpeg -i input.mp4 -vf "scale=1280:-2" output.mp4

Compress Video

Good quality, smaller file (CRF 23 is default, lower = better quality)

ffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output.mp4

Aggressive compression for web preview

ffmpeg -i input.mp4 -c:v libx264 -crf 28 -preset fast -c:a aac -b:a 96k output.mp4

Target file size (e.g., ~10MB for 60s video = ~1.3Mbps)

ffmpeg -i input.mp4 -c:v libx264 -b:v 1300k -c:a aac -b:a 128k output.mp4

Extract Audio

Extract to MP3

ffmpeg -i input.mp4 -vn -acodec libmp3lame -q:a 2 output.mp3

Extract to AAC

ffmpeg -i input.mp4 -vn -acodec aac -b:a 192k output.m4a

Extract to WAV (uncompressed)

ffmpeg -i input.mp4 -vn output.wav

Convert Audio Formats

M4A to MP3 (for ElevenLabs voice samples)

ffmpeg -i input.m4a -codec:a libmp3lame -qscale:a 2 output.mp3

WAV to MP3

ffmpeg -i input.wav -codec:a libmp3lame -b:a 192k output.mp3

Adjust volume

ffmpeg -i input.mp3 -filter:a "volume=1.5" output.mp3

Trim/Cut Video

Cut from timestamp to duration (recommended - reliable)

ffmpeg -i input.mp4 -ss 00:00:30 -t 00:00:15 -c:v libx264 -c:a aac output.mp4

Cut from timestamp to timestamp

ffmpeg -i input.mp4 -ss 00:00:30 -to 00:00:45 -c:v libx264 -c:a aac output.mp4

Stream copy (faster but may lose frames at cut points)

Only use when source has frequent keyframes

ffmpeg -i input.mp4 -ss 00:00:30 -t 00:00:15 -c copy output.mp4

Note: Re-encoding is recommended for trimming. Stream copy (-c copy ) can silently drop video if the seek point doesn't align with a keyframe.

Speed Up / Slow Down

2x speed (video and audio)

ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" output.mp4

0.5x speed (slow motion)

ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]atempo=0.5[a]" -map "[v]" -map "[a]" output.mp4

Video only (no audio)

ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" -an output.mp4

Concatenate Videos

Create file list

echo "file 'clip1.mp4'" > list.txt echo "file 'clip2.mp4'" >> list.txt echo "file 'clip3.mp4'" >> list.txt

Concatenate (same codec/resolution)

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

Concatenate with re-encoding (different sources)

ffmpeg -f concat -safe 0 -i list.txt -c:v libx264 -c:a aac output.mp4

Add Fade In/Out

Fade in first 1 second, fade out last 1 second (30fps video)

ffmpeg -i input.mp4 -vf "fade=t=in:st=0:d=1,fade=t=out:st=9:d=1" -c:a copy output.mp4

Audio fade

ffmpeg -i input.mp4 -af "afade=t=in:st=0:d=1,afade=t=out:st=9:d=1" -c:v copy output.mp4

Get Video Info

Duration, resolution, codec info

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

Full info

ffprobe -v quiet -print_format json -show_format -show_streams input.mp4

Remotion-Specific Patterns

Video Speed Adjustment for Remotion

When to use FFmpeg vs Remotion playbackRate :

Scenario Use FFmpeg Use Remotion

Constant speed (1.5x, 2x) Either works ✅ Simpler

Extreme speeds (>4x or <0.25x) ✅ More reliable May have issues

Variable speed (accelerate over time) ✅ Pre-process Complex workaround needed

Need perfect audio sync ✅ Guaranteed Usually fine

Demo needs to fit voiceover timing ✅ Pre-calculate Runtime adjustment

Remotion limitation: playbackRate must be constant. Dynamic interpolation like playbackRate={interpolate(frame, [0, 100], [1, 5])} won't work correctly because Remotion evaluates frames independently.

Speed up demo to fit a scene (e.g., 60s demo into 20s = 3x speed)

ffmpeg -i demo-raw.mp4
-filter_complex "[0:v]setpts=0.333*PTS[v];[0:a]atempo=3.0[a]"
-map "[v]" -map "[a]"
public/demos/demo-fast.mp4

Slow motion for emphasis (0.5x speed)

ffmpeg -i action.mp4
-filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]atempo=0.5[a]"
-map "[v]" -map "[a]"
public/demos/action-slow.mp4

Speed up without audio (common for screen recordings)

ffmpeg -i demo.mp4 -filter:v "setpts=0.5*PTS" -an public/demos/demo-2x.mp4

Timelapse effect (10x speed, drop audio)

ffmpeg -i long-demo.mp4 -filter:v "setpts=0.1*PTS" -an public/demos/timelapse.mp4

Calculate speed factor:

• To fit X seconds of video into Y seconds of scene: speed = X / Y

• setpts multiplier = 1 / speed (e.g., 3x speed = setpts=0.333*PTS)

• atempo value = speed (e.g., 3x speed = atempo=3.0)

Extreme speed (>2x audio): Chain atempo filters (each limited to 0.5-2.0 range):

4x speed audio

-filter_complex "[0:a]atempo=2.0,atempo=2.0[a]"

8x speed audio

-filter_complex "[0:a]atempo=2.0,atempo=2.0,atempo=2.0[a]"

Prepare Demo Recording for Remotion

Standard 1080p, 30fps, Remotion-ready

ffmpeg -i raw-recording.mp4
-vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,fps=30"
-c:v libx264 -crf 18 -preset slow
-c:a aac -b:a 192k
-movflags faststart
public/demos/demo.mp4

Screen Recording to Remotion Asset

From iPhone/iPad recording (usually 60fps, variable resolution)

ffmpeg -i iphone-recording.mov
-vf "scale=1920:-2,fps=30"
-c:v libx264 -crf 20
-an
public/demos/mobile-demo.mp4

Batch Convert GIFs

for f in assets/*.gif; do ffmpeg -i "$f" -movflags faststart -pix_fmt yuv420p
-vf "scale=trunc(iw/2)*2:trunc(ih/2)*2"
"public/demos/$(basename "$f" .gif).mp4" done

Common Issues

"Height not divisible by 2"

Add scale filter: -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2"

Video won't play in browser

Use: -movflags faststart -pix_fmt yuv420p -c:v libx264

Audio out of sync after speed change

Use filter_complex with atempo: -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]"

File too large

Increase CRF (23→28) or reduce resolution

Quality Guidelines

Use Case CRF Preset Notes

Archive/Master 18 slow Best quality, large files

Production 20-22 medium Good balance

Web/Preview 23-25 fast Smaller files

Draft/Quick 28+ veryfast Fast encoding

Platform-Specific Output Optimization

After Remotion renders your video (typically to out/video.mp4 ), use FFmpeg to optimize for each distribution platform.

Workflow Integration

Remotion render (master) FFmpeg optimization Platform upload ↓ ↓ ↓ out/video.mp4 ────────→ out/video-youtube.mp4 ───→ YouTube ────────→ out/video-twitter.mp4 ───→ Twitter/X ────────→ out/video-linkedin.mp4 ───→ LinkedIn ────────→ out/video-web.mp4 ───→ Website embed

YouTube (Recommended Settings)

YouTube re-encodes everything, so upload high quality:

YouTube optimized (1080p)

ffmpeg -i out/video.mp4
-c:v libx264 -preset slow -crf 18
-profile:v high -level 4.0
-bf 2 -g 30
-c:a aac -b:a 192k -ar 48000
-movflags +faststart
out/video-youtube.mp4

YouTube Shorts (vertical 1080x1920)

ffmpeg -i out/video.mp4
-vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2"
-c:v libx264 -crf 18 -c:a aac -b:a 192k
out/video-shorts.mp4

Twitter/X

Twitter has strict limits: max 140s, 512MB, 1920x1200:

Twitter optimized (under 15MB target for fast upload)

ffmpeg -i out/video.mp4
-c:v libx264 -preset medium -crf 24
-profile:v main -level 3.1
-vf "scale='min(1280,iw)':'min(720,ih)':force_original_aspect_ratio=decrease"
-c:a aac -b:a 128k -ar 44100
-movflags +faststart
-fs 15M
out/video-twitter.mp4

Check file size and duration

ffprobe -v error -show_entries format=duration,size -of csv=p=0 out/video-twitter.mp4

LinkedIn

LinkedIn prefers MP4 with AAC audio, max 10 minutes:

LinkedIn optimized

ffmpeg -i out/video.mp4
-c:v libx264 -preset medium -crf 22
-profile:v main
-vf "scale='min(1920,iw)':'min(1080,ih)':force_original_aspect_ratio=decrease"
-c:a aac -b:a 192k -ar 48000
-movflags +faststart
out/video-linkedin.mp4

Website/Embed (Optimized for Fast Loading)

Web-optimized MP4 (small file, progressive loading)

ffmpeg -i out/video.mp4
-c:v libx264 -preset medium -crf 26
-profile:v baseline -level 3.0
-vf "scale=1280:720"
-c:a aac -b:a 128k
-movflags +faststart
out/video-web.mp4

WebM alternative (better compression, wider browser support)

ffmpeg -i out/video.mp4
-c:v libvpx-vp9 -crf 30 -b:v 0
-vf "scale=1280:720"
-c:a libopus -b:a 128k
-deadline good
out/video-web.webm

GIF (for Previews/Thumbnails)

High-quality GIF (first 5 seconds)

ffmpeg -i out/video.mp4 -t 5
-vf "fps=15,scale=480:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse"
out/preview.gif

Smaller file GIF

ffmpeg -i out/video.mp4 -t 3
-vf "fps=10,scale=320:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse"
out/preview-small.gif

Platform Requirements Quick Reference

Platform Max Resolution Max Size Max Duration Audio

YouTube 8K 256GB 12 hours AAC 48kHz

Twitter/X 1920x1200 512MB 140s AAC 44.1kHz

LinkedIn 4096x2304 5GB 10 min AAC 48kHz

Instagram Feed 1080x1350 4GB 60s AAC 48kHz

Instagram Reels 1080x1920 4GB 90s AAC 48kHz

TikTok 1080x1920 287MB 10 min AAC

Batch Export for All Platforms

#!/bin/bash

save as: export-all-platforms.sh

INPUT="out/video.mp4"

YouTube (high quality)

ffmpeg -i "$INPUT" -c:v libx264 -preset slow -crf 18
-c:a aac -b:a 192k -movflags +faststart
out/video-youtube.mp4

Twitter (compressed)

ffmpeg -i "$INPUT" -c:v libx264 -crf 24
-vf "scale='min(1280,iw)':'-2'"
-c:a aac -b:a 128k -movflags +faststart
out/video-twitter.mp4

LinkedIn

ffmpeg -i "$INPUT" -c:v libx264 -crf 22
-c:a aac -b:a 192k -movflags +faststart
out/video-linkedin.mp4

Web embed (small)

ffmpeg -i "$INPUT" -c:v libx264 -crf 26
-vf "scale=1280:720"
-c:a aac -b:a 128k -movflags +faststart
out/video-web.mp4

echo "Exported:" ls -lh out/video-*.mp4

Error Handling

Common errors and fixes when processing video:

Check if FFmpeg succeeded

ffmpeg -i input.mp4 -c:v libx264 output.mp4 && echo "Success" || echo "Failed: check input file"

Validate output file is playable

ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of csv=p=0 output.mp4

Get detailed error info

ffmpeg -v error -i input.mp4 -f null - 2>&1 | head -20

Handling Common Failures

Error Cause Fix

"No such file" Input path wrong Check path, use quotes for spaces

"Invalid data" Corrupted input Re-download or re-record source

"height not divisible by 2" Odd dimensions Add scale filter with trunc

"encoder not found" Missing codec Install FFmpeg with full codecs

Output 0 bytes Silent failure Check full ffmpeg output for errors

Feedback & Contributions

If this skill is missing information or could be improved:

• Missing a command? Describe what you needed

• Found an error? Let me know what's wrong

• Want to contribute? I can help you:

• Update this skill with improvements

• Create a PR to github.com/digitalsamba/claude-code-video-toolkit

Just say "improve this skill" and I'll guide you through updating .claude/skills/ffmpeg/SKILL.md .