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ffmpeg.md

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ffmpeg

inspect <file>

ffmpeg -i <file>

image ↔ video

# image sequence <prefixN.jpg> → video
ffmpeg -f image2 -i <prefix%d.jpg> <outfile>

# video → image sequence
ffmpeg -i <infile> <prefix%4d.jpg>

# video → gif
ffmpeg -i <infile> <outfile.gif>
ffmpeg -i <infile> -pix_fmt rgb24 -r 25 -s 200x100 -ss 00:00:05.200 -t 00:00:03 <outfile>

Supported formats: pgm, ppm, pam, pgmyuv, jpeg, gif, png, tiff, sgi

re-encode a video in a specific format

ffmpeg -i <infile> <outfile>
  • Audio codec: aac
  • Audio bitrate: 128kb/s
  • Video codec: mpeg4
  • Video bitrate: 1200kb/s
  • Video size: 320x180
ffmpeg -i <infile> input \
       -acodec aac -ab 128kb \
       -vcodec mpeg4 -b 1200kb \
       -mbd 2 -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2 \
       -s 320x180 \
       -title <Title> \
       <outfile.mp4>

extract audio from video

  • Audio codec: mp3
  • Audio sample rate: 44.1kHz
  • Audio bitrate: 192 kbps
ffmpeg -i <infile> -vn -ar 44100 -ac 2 -ab 192 -f mp3 <outfile.mp3>

combine video and audio

ffmpeg -i <if>.wav -i <if> <of>

using bchunk to split audio using a cue file

ffmpeg -i file.ape file.wav
bchunk -w file.cue file.wav prefix

add time to end of video

Command uses a "nullsrc" video as base, and our source video as "overlay". The overlay filter will "freeze" the overlay when the duration of the nullsrc video is longer.

Source video with resolution (1376x1024), duration (30s), and framerate (10 fps): nullsrc=s=1376x1024:d=30:r=10

Overlay filter: [0:v][1:v]overlay[video]

Assign first input as base layer, and second video as overlay:

ffmpeg -f lavfi \
       -i nullsrc=s=1376x1024:d=30:r=10 \
       -i infile.mp4 \
       -filter_complex "[0:v][1:v]overlay[video]" \
       -map "[video]" -an -shortest \
       outfile.mp4

alter speed / framerate

video

# e.g. double speed with setpts (factor 0.5):
ffmpeg -i input.mkv -filter:v "setpts=0.5*PTS" output.mkv
# modify framerate with `-r <framerate>` to prevent framedrop

audio

# e.g. quadruple speed with atempo (factor 4.0):
ffmpeg -i input.mkv -filter:a "atempo=2.0,atempo=2.0" -vn output.mkv
# the atempo filter must be [0.5, 2.0], but we can repeat it

both

# filter both audio and video with `filter_complex`:
ffmpeg -i input.mkv \
       -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" \
       -map "[v]" -map "[a]" \
       output.mkv

filter primer

# video filter
ffmpeg -i infile -filter:v "<filter>" outfile
ffmpeg -i infile -vf "<filter>" outfile

# audio filter

ffmpeg -i infile -filter:a "<filter>" outfile
ffmpeg -i infile -af "<filter>" outfile

# scale
# fix odd number resolution issue with scaling
ffmpeg -i infile \
       -filter:v "scale=trunc(iw/2)*2:trunc(ih/2)*2" \
       outfile

# crop video to width and height, starting at position x,y
ffmpeg -i infile \
       -filter:v "crop=width:height:x:y" \
       outfile