FFmpeg

• Installing ffmpeg on macOS

  brew install ffmpeg
  

Filetype Conversions

Conversions between filetypes is usually as easy as the following example

• Encode an MP3 audio file input.mp3 as an AIFF file, and save it as output.aiff

  ffmpeg -i 'input.mp3' 'output.aiff'
  

• Convert an MP3 file song.mp3 into M4A format:

  • Using avconvert:

    avconvert -p 'PresetAppleM4A' -s 'song.mp3' -o 'song.m4a'
    

  • Using ffmpeg:

    ffmpeg -i 'song.mp3' -c:a aac -c:v copy 'book.m4a'
    

• Encode an MP4 video file input.mp4 as a GIF file, and save it as output.gif

  ffmpeg -i 'input.mp4' 'output.gif'
  

• Encode an audiobook AAX file input.aax as a M4B file, and save it as output.m4b

  # Assuming you know the activation bytes of your file...
  ffmpeg -activation_bytes ACTIVATION_BYTES -i BOOK.aax -c copy BOOK.m4b
  

• Convert an audiobook from MP3 to M4B:

  ffmpeg -i BOOK.mp3 -c:a aac -c:v copy BOOK.m4b
  

  mp3='book.mp3'
  m4a=${mp3:r}.m4a
  m4b=${m4a:r}.m4b
  jpeg=${mp3:r}.jpeg
  
  # Extract the cover art from an MP3 file
  ffmpeg \
      -i ${mp3} \
      -map 0:v \
      -map -0:V \
      -c copy \
      ${jpeg}
  
  # https://stackoverflow.com/questions/18710992/how-to-add-album-art-with-ffmpeg
  # Convert the audiobook from MP3 to M4B
  # preserving the existing cover art
  ffmpeg \
      -i ${mp3} \
      -i ${jpeg} \
      -map 0:0 \
      -map 1:0 \
      -c:a aac \
      -c:v copy \
      -id3v2_version 4 \
      -metadata:s:v title="Album cover" \
      -metadata:s:v comment="Cover (front)" \
      ${m4b}
  

• Convert each MP3 audio file in the current folder as an M4A file, save it with the same name, (i.e., example.mp3 → example.m4a)

  # For each audiobook in the folder
  for audiobook in *.mp3; do
      ffmpeg -i ${audiobook} -c:a aac -c:v copy ${audiobook:r}.m4a;
  done
  

Useful Arguments

• -f <format>: Forcibly specify the input/output format, (usually set automatically)

• -y: Automatically overwrite files without asking

• -i <ifile>: Specify an input filename

• -loglevel panic: Reduce the verbosity of ffmpeg (in this case, silence it)

• loglevel quiet -stats: Don't print any output other than the a one-line "progress report" of the conversion that's currently underway

• -activation_bytes <hash>: The hexadecimal activation bytes used to decrypt Audible's DRM

• Overwrite the file exists.mp4 without prompting for confirmation

  touch exists.mp4
  ffmpeg -i 'input.mp4' -y 'exists.mp4'
  

Merging audio files

• Concatenate multiple MP3 files together, into a single merged MP3 file

  • Example 1

    ls *.mp3 | sort | sed 's/^/file /g' > 'files.txt'
    ffmpeg -f 'concat' -i 'files.txt' -c copy 'merged.mp3'
    

  • Example 2

    # Create a string to specify which files to concatenate
    ifile="concat:one.mp3|two.mp3|three.mp3"
    
    # Concatenate the files
    ffmpeg -i ${ifile} -c:a copy -map_metadata 0:1 ofile.mp3
    

• Extract the cover art from music file

  ffmpeg -i MUSIC_FILE.m4a -map 0:v -map -0:V -c copy 'cover_art.jpg'
  

• Convert every MKV file in a folder to MP4 format

  for file in ~/episodes/*.mkv; do
      ffmpeg -i ${file} ${file:0:(-4)}.mp4;
  done
  

• Use the built-in camera to take a photo

  ffmpeg \
      -f 'avfoundation' \
      -video_size '1280x720' \
      -framerate 30 \
      -i 0 \
      -vframes 1 \
      './output.jpg'
  

• Use the built-in microphone to record audio

  # `-f` force the use of AVFoundation format
  # `-i :1` record audio from the built-in microphone
  # `-t 10` record audio for 10 seconds
  ffmpeg -f avfoundation -i ":1" -t 10 'output.mp3'
  

• Use the system default camera and microphone to record a video

  typeset -i duration=4
  typeset -i framerate=30
  
  ffmpeg -f 'avfoundation' \
      -video_size '1280x720' \
      -framerate ${framerate} \
      -i '0:0' \
      -vframes $((${framerate}*${duration})) \
      './output.mkv'