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• Creating an MP4 video with ffmpeg from timestamped JPEG frames received by pipe

  16 août 2024, par Denis Fevralev

  I need to create a video with following conditions :

  


  

  1. It can only be made from a sequence of JPEG files, each having its timestamp (milliseconds) in the name. The images' durations are not the same, they differ, so i cannot just concat them all and use particular fps

  


  2. There are several tar archives with the images sequences, the archives are kind of huge so I read them from a file storage as an async steam of data and cannot save them on the disk as files. The frames are read and right away put to ffmpeg running process stdin.

  


  3. The images may have different aspect ratios so it's required to make a NxN square and scale the images to fit in with filling the empty space with pads

  


  


  My current solution :

  


  ffmpeg -r $someFpsValue -i - -vf scale=w=$w:h=$h:force_original_aspect_ratio=1,pad=$w:$h:(((ow-iw)/2)):(((oh-ih)/2)) result.mp4


  


  As you can see, it doesn't let me concat the images with correct durations. I know that the concat demuxer can solve the problem of merging images with different durations but seemingly it doesn't work with pipe protocol. I have an idea of evaluating an average fps as (videoFramesCount) / (videoDurationInSeconds) for -r argument, or maybe even counting the fps for each video's second and then getting the avg, but maybe there is a more reliable solution (like some concat demuxer analogue) ?

  


  Thanks in advance :)

  


• FFMPEG : How to create video using 1 file .mov (transparent) and 1 image (.jpg)

  29 mai 2017, par Jim2k

  How to create video using 1 file .mov loop (transparent) and 1 image (.jpg Full length video)
  like same : https://www.youtube.com/watch?v=fXzh3sMxTpM

   !!!Sorry for my poor english !!!

• appending a string constant selectively within a while loop in bash

  29 janvier 2017, par Maxwell Chandler

  I have a script called automateutube that I edit in VIM and execute in the terminal with sh ./automateutube.sh This script pulls youtube links from a file called songs.txt and downloads the video from youtube then extracts the audio.

  The songs.txt file looks like this

  https://www.youtube.com/watch?v=IxQOlZ3pqtI
  
  https://www.youtube.com/watch?v=IxQOlZ3pqtI
  
  https://www.youtube.com/watch?v=IxQOlZ3pqtI
  
  https://www.youtube.com/watch?v=IxQOlZ3pqtI

  It is just a bunch of links, one per line.

  The script looks like this

  #!/bin/bash
  
  
  
  while read p; do    
  
  
  
  x=/tmp/.youtube-dl-$(date +%y.%m.%d_%H.%M.%S)-$RANDOM.flv
  
  
  
  youtube-dl --audio-quality 160k --output=$x --format=18 "$p"
  
  
  
  ffmpeg -i $x -acodec libmp3lame -ac 2 -ab 128k -vn -y "$p"
  
  
  
  rm $x
  
  
  
  done code>

  Now the first part executes. It downloads the video and starts to unpack it.

  It is the second part that fails. ffmpeg -i $x -acodec libmp3lame -ac 2 -ab 128k -vn -y "$p"

  This is because "$p" is supposed to be in format "filename.mp3" However as it is p takes the value of a youtube link, without ".mp3" appended.

  This works for the first line

  youtube-dl --audio-quality 160k --output=$x --format=18 "$p"

  because "$p" is supposed to be in the form of a link there.

  Now I have tried adding three lines in

  a="$.mp3"
  
  b="$p"
  
  c=$b$a

  and making ffmpeg -i $x -acodec libmp3lame -ac 2 -ab 128k -vn -y "$p"

  into ffmpeg -i $x -acodec libmp3lame -ac 2 -ab 128k -vn -y "$c"

  but I am still getting an error. Any ideas ?

  parse error, at least 3 arguments were expected, only 1 given in string ’om/watch ?v=sOAHOxbMOJY’