# quickly check the integrity of video files inside a directory with ffmpeg
find . -name "*.mp4" -exec sh -c "ffmpeg -v error -i '{}' -map 0:1 -f null - 2>'{}.log'" \;

 
# extract audio track from movie
$ ffmpeg -i $MOVIE -vn -acodec copy $AUDIO_MOVIE

# extract audio track from reaction
$ ffmpeg -i $REACTION -vn -acodec copy $AUDIO_REACTION


$ ffmpeg -f lavfi -i color=size=1280x528:rate=24:duration=136  -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -video_track_timescale 16k -shortest black.mp4
$ ffmpeg -f lavfi -i color=size=1280x528:rate=925:duration=136 -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=48000 -video_track_timescale 95k -shortest black.mp4
  
  
# # embed reaction into movie
$ ffmpeg -i ./28.0.mp4 -i ./reaction-28.mp4 -filter_complex "[1:v]scale=500:-1[v2];[0:v][v2]overlay=main_w-overlay_w-5:5" -c:v libx264 -c:a copy "reaction-lotr-rotk.0.1.mp4"
  
# # merge reaction / movie tracks
$ ffmpeg -i reaction.0.aac -i movie.0.aac -filter_complex "[0][1]amerge=inputs=2,pan=stereo|FL<c0+c1|FR<c2+c3[a]" -map "[a]" audio-final.aac
  
# # apply new reaction audio track to new reaction video
$ ffmpeg -i audio-final.aac -i lotr-rotk-extended.final.mp4 -c:v copy -c:a aac lotr-rotk-extended.final.mp4
  
  
  
$ ffprobe -i "Reacts With Jax, The Lord of the Rings: Return of the King.mp4" -show_entries format=duration -v quiet -of csv="p=0"