yuanqing / ffmpeg-cheatsheet

:vhs: A cheatsheet for common video processing operations in FFmpeg

FFmpeg Cheatsheet

A cheatsheet for common video processing operations in FFmpeg

Operations

Use the -y flag to override the output file if it exists.

Audio-video sync

Reference

# Delay audio by 3 seconds
$ ffmpeg -i input.mov -itsoffset 3 -i input.mov -map 0:v -map 1:a -codec:a copy -codec:v copy output.mov

# Delay video by 3 seconds (ie. advance audio by 3 seconds)
$ ffmpeg -i input.mov -itsoffset 3 -i input.mov -map 1:v -map 0:a -codec:a copy -codec:v copy output.mov

• The second -i flag must come immediately after the -itsoffset flag.

Crop

Reference

# Crop to width 360, height 640
$ ffmpeg -i input.mov -filter:v 'crop=360:640:0:0' -codec:a copy output.mov

# Crop to width 360, height 640, starting from coordinates (10, 20)
$ ffmpeg -i input.mov -filter:v 'crop=360:640:10:20' -codec:a copy output.mov

Format

Reference

# Convert to GIF
$ ffmpeg -i input.mov output.gif

# Convert from GIF
$ ffmpeg -i input.gif output.mov

# Convert between non-GIF formats
$ ffmpeg -i input.mov -codec:v copy -codec:a copy output.mp4

Frame rate

Reference

# Change the frame rate to 12
$ ffmpeg -i input.mov -filter:v 'fps=fps=12' -codec:a copy output.mov

Strip audio

Reference

# Remove audio
$ ffmpeg -i input.mov -codec:v copy -an output.mov

Resize

Reference

# Resize to width 360, height 640
$ ffmpeg -i input.mov -filter:v 'scale=360:640' -codec:a copy output.mov

# Resize to width 360, maintaining the aspect ratio
$ ffmpeg -i input.mov -filter:v 'scale=360:-1' -codec:a copy output.mov

# Resize to height 640, maintaining the aspect ratio
$ ffmpeg -i input.mov -filter:v 'scale=-1:640' -codec:a copy output.mov

• Set either width or height to -1 to maintain the aspect ratio.

Reverse

Reference

# Reverse
$ ffmpeg -i input.mov -filter:v 'reverse' -filter:a 'areverse' output.mov

Rotate

Reference

# Rotate 90 degrees clockwise
$ ffmpeg -i input.mov -filter:v 'transpose=1' -codec:a copy output.mov

# Rotate 90 degrees counter-clockwise
$ ffmpeg -i input.mov -filter:v 'transpose=2' -codec:a copy output.mov

# Rotate 180 degrees
$ ffmpeg -i input.mov -filter:v 'transpose=1,transpose=1' -codec:a copy output.mov

Speed

Reference

# Quarter the speed
$ ffmpeg -i input.mov -filter:v 'setpts=4*PTS' -filter:a 'atempo=0.5,atempo=0.5' output.mov

# Halve the speed
$ ffmpeg -i input.mov -filter:v 'setpts=2*PTS' -filter:a 'atempo=0.5' output.mov

# Double the speed
$ ffmpeg -i input.mov -filter:v 'setpts=0.5*PTS' -filter:a 'atempo=2' output.mov

# Quadruple the speed
$ ffmpeg -i input.mov -filter:v 'setpts=0.25*PTS' -filter:a 'atempo=2,atempo=2' output.mov

• Use the formula 1 ÷ speed to compute the value of setpts.

  • Half the speed: setpts=2*PTS since 1 ÷ 0.5 = 2.
  • Double the speed: setpts=0.5*PTS since 1 ÷ 2 = 0.5.

• The value of each atempo filter must be between 0.5 and 2.

  • Quarter the speed: atempo=0.5,atempo=0.5 since 0.5 × 0.5 = 0.25.
  • Quadruple the speed: atempo=2,atempo=2 since 2 × 2 = 4.

Subtitles

Reference

# Write subtitles into video
$ ffmpeg -i input.mov -filter:v 'subtitles=subtitles.srt' -codec:a copy output.mov

# Write subtitles into video, with custom subtitle styles
$ ffmpeg -i input.mov -filter:v "subtitles=subtitles.srt:force_style='FontName=Menlo Bold,Fontsize=18'" -codec:a copy output.mov

Trim

Reference

# Trim from 0:05 to 0:10
$ ffmpeg -ss 0:05 -to 0:10 -i input.mov -codec:v copy -codec:a copy output.mov

# Trim from 0:05 to the end of the video
$ ffmpeg -ss 0:05 -i input.mov -codec:v copy -codec:a copy output.mov

• The -ss and -to flags must come before the -i flag.

Volume

Reference

# Halve the volume
$ ffmpeg -i input.mov -codec:v copy -filter:a 'volume=0.5' output.mov

# Double the volume
$ ffmpeg -i input.mov -codec:v copy -filter:a 'volume=2' output.mov

Relevant CLI flags

Reference

ffmpeg
  -an
  -ss <timestamp>
  -to <timestamp>
  -itsoffset <offset>
  -i <input>
  -map <stream>
  -codec:a <codec>
  -codec:v <codec>
  -filter:a <filtergraph>
  -filter:v <filtergraph>
  -y
  <output>

See also

• vdx