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• split the video into five chunks using ffmpeg and batch script

  21 janvier 2019, par RJFF

  I want to split videos into five chunks using ffmpeg

  the first chunk represents 20% of the whole video
  the second chunk represents 40% of the whole video
  the third chunk represents 60% of the whole video
  the fourth chunk represents 80% of the whole video

  the fifth chunk represents 100% of the whole video

  I write the algorithm but I do not know how to write the batch code :
  1. find the duration of the video
  2. store the duration in variable
  3. divided the duration by 5
  4. split the video

  I want a batch script that takes the duration of the video then store the value of duration in the variable

  this is how I can take the duration of the video

  ffmpeg -i C:\video-splitter-master\1.avi 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }'

  but how I can store the duration value in the variable ?

  can you please help me ?

• Creating forks of `ffmpeg` in loop inside a shell script "loses" some iterations

  19 octobre 2015, par sschaef

  I have a shell script that takes a directory as input, reads all mp4 files in it and convert them to a mp3 with ffmpeg :

  #!/bin/bash
  
  
  
  dir=$1
  
  
  
  while read -rd "" file
  
  do
  
    base=$(basename "$file")
  
    filename=${base%(*}".mp3"
  
    ffmpeg -i "$file" -vn -ar 44100 -ac 2 -ab 192000 -f mp3 "$filename" &
  
  done < <(find $dir -maxdepth 1 -iname "*.mp4" -print0)
  
  
  
  wait
  
  
  
  exit 0

  Currently all these calls to ffmpeg are forked because when I leave out the & at the end only the first file in converted and the others are ignored.

  But this is problematic because somethings this fails on some files error messages like the following :

  path/to/file/file name - with spaces(info)(temp_information).mp4 : No such file or directory

  All file names normally contain spaces, maybe that is the reason why it fails for some files.

  Thus, I have the following questions :

  1. When I don’t fork the ffmpeg calls why is only the first file executed ? I expected that the loop waits until the process is finished and then continues with the next iteration.
  2. Why is the script unable to find some files (maybe it is a problem of ffmpeg) ?
  3. How to solve all these problems and make the script to work ?

• FFMPEG - Merge two videos with timecode sync

  25 mai 2022, par Olivier Rivard

  We are recording 2 videos from 2 cameras. There is a Timecode metadata attached two the 2 videos. But the starting and stopping of the 2 recodings could have a small difference in time. Less than a second, mostly couple of frames.

  


  One of the video has also the audio recording.
We used ffprobe to extract timecode to analyze the difference.

  


  The difference in timecode won't always be the same.

  


  Ex :
video1.mov timecode : 20:41:11:21
video2.mov timecode : 20:41:11:52

  


  This is the current command that we use to combine the 2 videos side by side to have a look similar to a Zoom call. The only issue is that our videos are out of sync.

  


  ./ffmpeg -i video1.mov -i video2.mov -filter_complex "[0:v]pad=iw*2:ih[int]; [int][1:v]overlay=W/2:0[vid]; [0:a][1:a]amix=inputs=2:duration=longest[aud]" -r 30 -map [vid]" -map "[aud]" output.mp4


  


  We want to make sure that the 2 videos are sync by the timecode.

  


  Example of a combine video :