Some handy ffmpeg functions I use everyday.

ffmpeg-bash-handy-functions.sh

#
# VIDEO / IMAGE RELATED
#
# requires: ffmpeg
# tip: put this funcion on your ~/.profile file
#



# Compress video files while keep their quality
# Usage: compress video_file
compress() {
  sourcefile=$(basename "$1")
  filename="${sourcefile%.*}"
  ffmpeg -i ${sourcefile} -c:v libx264 -crf 24 -b:v 1M -c:a aac -strict -2 "${filename}"_compressed.mp4
}


# Convert video to gif file.
# Usage: video2gif video_file (scale) (fps)
video2gif() {
  sourcefile=$(basename "$1") 
  filename="${sourcefile%.*}"
  ffmpeg -y -i "${1}" -vf fps=${3:-10},scale=${2:-320}:-1:flags=lanczos,palettegen "${filename}.png"
  ffmpeg -i "${1}" -i "${filename}.png" -filter_complex "fps=${3:-10},scale=${2:-320}:-1:flags=lanczos[x];[x][1:v]paletteuse" "${filename}".gif
  rm "${filename}.png"
}

# Rescale video to file.
# Usage: rescale video_file desired_width
# example, will rescale a video to width = 640 keeping aspect ratio: 
# rescale video_file 640
rescale() {
  sourcefile=$(basename "$1")
  filename="${sourcefile%.*}"
  ffmpeg -i ${sourcefile} -vf scale=${2:-320}:-1 "${filename}_scaled.mp4"
}

# Speed up video to file.
# Usage: speedup video_file
# tip: could be used to optimize file size too
speedup() {
  sourcefile=$(basename "$1")
  filename="${sourcefile%.*}"
  ffmpeg -i ${sourcefile} -r 16 -filter:v "setpts=0.5*PTS" "${filename}"_faster.mp4
}

# Speed down video to file.
# Usage: speedup video_file
# tip: could be used to optimize file size too
speeddn() {
  sourcefile=$(basename "$1")
  filename="${sourcefile%.*}"
  ffmpeg -i ${sourcefile} -r 16 -filter:v "setpts=2*PTS" "${filename}"_slower.mp4
}