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ffmpeg_notes [2019-08-02 14:05] – nikffmpeg_notes [2023-08-27 12:27] (current) – [general exploration] nik
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 ==== Ffmpeg - various notes ==== ==== Ffmpeg - various notes ====
 +
 +==== general exploration ====
 +
 +[[https://ffmpeg.lav.io/|FFmpeg Explorer]] is a tool to help you explore FFmpeg filters.
 +
 +==== add audio track to a video ====
 +
 +''ffmpeg -i input.mkv -i audio.mp3 -c copy output.mkv''
 +
 +====extract audio from mp4 as mp3====
 +
 +''ffmpeg -i input.mp4 -b:a 320K -vn output-audio.mp3''
 +
 +====avoid audio/video reencode====
 +
 +options '-c:a copy' and '-c:v copy'
  
 ====slo-mo video transcode (e.g. iphone)==== ====slo-mo video transcode (e.g. iphone)====
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 ''for file in `/bin/ls -1`; do ffmpeg -i $file -filter "setpts=6.0*PTS" -r 30 -an $file.30fps.mp4 ; done'' ''for file in `/bin/ls -1`; do ffmpeg -i $file -filter "setpts=6.0*PTS" -r 30 -an $file.30fps.mp4 ; done''
  
-====video -> image sequence====+====video → image sequence==== 
 + 
 +...timelapsed (1 frame every 4 seconds)
  
 ''ffmpeg -i IMG_4566.MOV -r 0.25 IMG_4566_seq/output_%05d.png'' ''ffmpeg -i IMG_4566.MOV -r 0.25 IMG_4566_seq/output_%05d.png''
  
 +====image sequence  → video====
 +
 +''ffmpeg -i %05d.jpg -c:v libx265 -r 25 out.mkv''
 +==== concat ====
 +
 +create a list of files (e.g. named files.txt)\\
 +''file 'dust_and_shadow_28min.mp4' ''\\
 +''file 'dust_and_shadow_black.mp4' ''\\
 +
 +then...\\
 +''ffmpeg -f concat -i files.txt -c copy dust_and_shadow_30min.mp4''
 +
 +alternatively, partial automation...\\
 +''ls *.mp4 | while read each; do echo "file '$each'" >> files.txt; done\\
 +ffmpeg -f concat -i files.txt -c copy 000-qualia-RN101.mkv''
 +
 +also -> https://stackoverflow.com/questions/7333232/how-to-concatenate-two-mp4-files-using-ffmpeg
 ====ffmpeg filters  ==== ====ffmpeg filters  ====
  
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 ''ffmpeg -i clip.mov -i clip2.mov  -filter_complex vstack merged.mov'' ''ffmpeg -i clip.mov -i clip2.mov  -filter_complex vstack merged.mov''
  
- 
-====avoid audio/video reencode==== 
- 
-options '-c:a copy' and '-c:v copy' 
  
 ====blending=== ====blending===
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 ====etc==== ====etc====
 +  * tuning x265 output -> http://forum.doom9.org/showthread.php?t=172458
   * further examples -> https://hhsprings.bitbucket.io/docs/programming/examples/ffmpeg/index.html   * further examples -> https://hhsprings.bitbucket.io/docs/programming/examples/ffmpeg/index.html
   * An ffmpeg and SDL Tutorial or How to Write a Video Player in Less Than 1000 Lines (2015) http://dranger.com/ffmpeg/   * An ffmpeg and SDL Tutorial or How to Write a Video Player in Less Than 1000 Lines (2015) http://dranger.com/ffmpeg/
   * various examples -> https://oioiiooixiii.blogspot.com/   * various examples -> https://oioiiooixiii.blogspot.com/
  

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