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