Various ffmpeg commands

_ffmpeg.sh

# ffmpeg snippets

# ffmpeg-slowdown.sh: slow down all files in a directory
# ffmpeg-to-mp3.sh: convert all video files in a directory to mp3
# handbrake-bulk.sh: convert all webm fils in a folder to mp4

ffmpeg-slowdown.sh

# slow down all files in a directory

# slowing down to 75.7575..%
# so the PTS factor is 1/757575758 = 1.32

for file in /path/to/somewhere/*
do
  ffmpeg -i "$file"  -filter_complex "[0:v]setpts=1.32*PTS[v];[0:a]atempo=0.7575758[a]" -map "[v]" -map "[a]"   "${file/GAMES/GAMES_SLOW}" -y
done

ffmpeg-to-mp3.sh

# convert all video files in a directory to mp3

# using lame
for file in /path/to/somewhere/*.{mp4,webm}; do  -i "$file" -c:a libmp3lame "${file/somewhere/mp3}.mp3"; done

# using ffmpeg
for file in /path/to/somewhere/*.{mp4,webm}; do ffmpeg -i "$file" -c:a libmp3lame "${file/somewhere/mp3}.mp3"; done

handbrake-bulk.sh

# convert all webm fils in a folder to mp4

for file in /path/to/somewhere/**/*.webm
do
  HandBrakeCLI -Z "Fast 1080p30" -i "$file" -o "${file%.webm}.mp4"
done