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• bash loop through list of file paths - characters get removed when sending to ffmpeg [duplicate]

  9 octobre 2018, par Brad Johnson

  This question already has an answer here :

  • Bash while loop stops for no reason ?
    
    1 answer
    

  I have a text file that contains a list of paths to flac files I want to convert to wav. Here is a small section of it :

  /mnt/nfs/Music/Rob D/1995 - Clubbed To Death/Rob D - 02 - Clubbed To Death _Kurayamino Variation_.flac
  
  /mnt/nfs/Music/Blonde Redhead/2000 - Melody of Certain Damaged Lemons/11 - For the Damaged Coda.flac
  
  /mnt/nfs/Music/I Monster/2001 - Daydream In Blue/01 - Daydream In Blue.flac
  
  /mnt/nfs/Music/Moby/2002 - Extreme Ways/01 - Extreme Ways.flac
  
  /mnt/nfs/Music/RJD2/2002 - Deadringer/01 - The Horror.flac
  
  /mnt/nfs/Music/RJD2/2002 - Deadringer/03 - Smoke & Mirrors.flac
  
  /mnt/nfs/Music/RJD2/2002 - Deadringer/06 - Ghostwriter.flac
  
  /mnt/nfs/Music/RJD2/2002 - Deadringer/10 - Chicken-Bone Circuit.flac
  
  /mnt/nfs/Music/FC Kahuna/2003 - Hayling/01 - Hayling _Original_.flac
  
  /mnt/nfs/Music/Lamb/2003 - Between Darkness and Wonder/04 - Angelica.flac

  I’m trying to loop through it like so :

  while read -r line; do
  
   wavfile=$(basename "$line")
  
   wavfile="${wavfile%.*}"
  
   ffmpeg -i "$line" "$2/$wavfile.wav"
  
  done <$1

  ...where $1 is where I would pass the name of the text file and $2 is the destination directory.

  Here is the output with the irrelevant ffmpeg junk pruned out :

  Input #0, flac, from '/mnt/nfs/Music/Rob D/1995 - Clubbed To Death/Rob D - 02 - Clubbed To Death _Kurayamino Variation_.flac':
  
  ...
  
  Output #0, wav, to '/mnt/gray/Clubbed To Death/Rob D - 02 - Clubbed To Death _Kurayamino Variation_.wav':
  
  ...
  
  /nfs/Music/Blonde Redhead/2000 - Melody of Certain Damaged Lemons/11 - For the Damaged Coda.flac: No such file or directory
  
  ...
  
  Input #0, flac, from '/mnt/nfs/Music/I Monster/2001 - Daydream In Blue/01 - Daydream In Blue.flac':
  
  ...
  
  Output #0, wav, to '/mnt/gray/Clubbed To Death/01 - Daydream In Blue.wav':
  
  ...
  
  nt/nfs/Music/Moby/2002 - Extreme Ways/01 - Extreme Ways.flac: No such file or directory
  
  ...
  
  Input #0, flac, from '/mnt/nfs/Music/RJD2/2002 - Deadringer/01 - The Horror.flac':
  
  ...
  
  Output #0, wav, to '/mnt/gray/Clubbed To Death/01 - The Horror.wav':
  
  ...
  
  nt/nfs/Music/RJD2/2002 - Deadringer/03 - Smoke & Mirrors.flac: No such file or directory
  
  ...
  
  Input #0, flac, from '/mnt/nfs/Music/RJD2/2002 - Deadringer/06 - Ghostwriter.flac':
  
  ...
  
  Output #0, wav, to '/mnt/gray/Clubbed To Death/06 - Ghostwriter.wav':
  
  ...
  
  nt/nfs/Music/RJD2/2002 - Deadringer/10 - Chicken-Bone Circuit.flac: No such file or directory
  
  ...
  
  Input #0, flac, from '/mnt/nfs/Music/FC Kahuna/2003 - Hayling/01 - Hayling _Original_.flac':
  
  ...
  
  Output #0, wav, to '/mnt/gray/Clubbed To Death/01 - Hayling _Original_.wav':
  
  ...
  
  /nfs/Music/Lamb/2003 - Between Darkness and Wonder/04 - Angelica.flac: No such file or directory

  If you pay attention to the paths that ffmpeg reports don’t exist, you’ll see that a seemingly random number of characters has been removed from the beginning. This appears to happen on even numbered lines, but odd numbered lines work. I can only reproduce this behavior when using ffmpeg. If I replace the ffmpeg line with a simple echo statement, every file path is shown to be correct. How can this be ?

  Other suggestions of accomplishing this are also welcome, however I do need the files processed in the order by which I have them listed in the file.

• FFmpeg : MD5 hash of M3U8 playlists generated from same input video with different segment durations (after applying video filter) don't match

  30 juillet 2020, par Saurabh P Bhandari

  Here are a few commands I am using to convert and transize a video in MP4 format to a M3U8 playlist.

  


  For a given input video (MP4 format), generate multiple video segments with segment duration 30 seconds.

  


  ffmpeg -loglevel error -i input.mp4 -dn -sn -an -c:v copy -bsf:v h264_mp4toannexb -copyts -start_at_zero -f segment -segment_time 30 30%03d.mp4 -dn -sn -vn -c:a copy audio.aac


  


  Apply a video filter (in this case scaling) on each segment and convert it to a M3U8 format.

  


  ls 30*.mp4 | parallel 'ffmpeg -loglevel error -i {} -vf scale=-2:144 -hls_list_size 0 {}.m3u8'


  


  Store the list of m3u8 files generated in list.txt in this format file 'segment-name.m3u8'

  


  for f in 30*.m3u8; do echo "file '$f'" >> list.txt; done


  


  Using concat demuxer, combine all segment files (which are in M3U8 format) and the audio to get one final m3u8 playlist pointing to segments with duration of 10 seconds.

  


  ffmpeg -loglevel error -f concat -i list.txt -i audio.aac -c copy -hls_list_size 0 -hls_time 10 output_30.m3u8


  


  ---

  


  I can change the segment duration in the first step from 30 seconds to 60 seconds, and compare the MD5 hash of the final M3U8 playlist generated in both the cases using this command :

  


  ffmpeg -loglevel error -i <input m3u8="m3u8" playlist="playlist" /> -f md5 -&#xA;

  


  The MD5 hash of the output files differ, i.e., video streams of output_30.m3u8 and output_60.m3u8 are not the same.

  


  Can anyone elaborate on this ?

  


  (I expected the MD5 hash to be the same)

  


• ffmpeg : md5 of m3u8 playlists generated from same input video with different segment durations (after applying video filter) don't match

  15 juillet 2020, par Saurabh P Bhandari

  Here are a few commands I am using to convert and transize a video in mp4 format to a m3u8 playlist.

  


  For a given input video (mp4 format), generate multiple video only segments with segment duration 30s

  


  ffmpeg -loglevel error -i input.mp4 -dn -sn -an -c:v copy -bsf:v h264_mp4toannexb -copyts -start_at_zero -f segment -segment_time 30 30%03d.mp4 -dn -sn -vn -c:a copy audio.aac


  


  Apply video filter (in this case scaling) on each segment and convert it to a m3u8 format

  


  ls 30*.mp4 | parallel 'ffmpeg -loglevel error -i {} -vf scale=-2:144 -hls_list_size 0 {}.m3u8'


  


  Store the list of m3u8 files generated in list.txt in this format file 'segment-name.m3u8'

  


  for f in 30*.m3u8; do echo "file '$f'" >> list.txt; done


  


  Using concat demuxer, combine all segment files (which are in m3u8 format) and the audio to get one final m3u8 playlist pointing to segments with duration of 10s.

  


  ffmpeg -loglevel error -f concat -i list.txt -i audio.aac -c copy -hls_list_size 0 -hls_time 10 output_30.m3u8


  


  ---

  


  I can change the segment duration in the first step from 30s to 60s, and compare the md5 of the final m3u8 playlist generated in both the cases using this command

  


  ffmpeg -loglevel error -i <input m3u8="m3u8" playlist="playlist" /> -f md5 - &#xA;

  


  The md5 of the output files differ i.e video streams of output_30.m3u8 and output_60.m3u8 are not the same.

  


  Can anyone elaborate on this ?

  


  (I expected the md5 to be the same)