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• converting png to movies with R via ffmpeg

  10 mai 2021, par user237554

  I want to convert a series of *.png files to a movie with R and have installed ffmpeg in the root directory. I think the installation has been successful because if I type

  


       ffmpeg -version


  


  in terminal I get all of the version information etc., etc.

  


  I have my *.png files saved in the wd and in R I say

  


      imgs <- list.files(pattern="*.png")
        saveVideo({
        for(img in imgs){
          im <- magick::image_read(img)
          plot(as.raster(im))
        }
      })


  


  I get an error message that "the command ""ffmpeg"" is not available in your system. Please install FFmpeg". Is there something I need to do to get R and ffmpeg to talk to each other ? Again, from terminal, ffmpeg is in the directory and it looks like it installed.

  


  thanks

  


• Get thumbnail image from video not working with PHP and ffmpeg (Ubuntu)

  20 décembre 2018, par a_pajic

  I have generated a $cmd string :

  ffmpeg -i /home/alen/www/mysite/video/Guitarist-139.mp4 -an -ss 0 -s
  1280x720 /home/alen/www/mysite/img/Guitarist-139.jpg

  then I have typing a command in PHP :

  shell_exec($cmd);

  but not working,

  then I have pasted this string in terminal but in terminal work perfectly.

  What is wrong.

• When I run `ffmpeg` in the background, how do I prevent `suspended (tty output)` ?

  4 novembre 2017, par Jim DeLaHunt

  I have a sh script which calls ffmpeg on several files. When I try to run this script in the background, redirecting output to a file, the job starts but then immediately suspends :

  % bin/mp3convert.sh path/a/b &> ~/tmp/log.txt &
  
  [1] 93352
  
  % 
  
  [1]  + suspended (tty output)  bin/mp3convert.sh path/a/b &> 

  If I try making the script continue in the background, it immediately suspends again :

  % jobs
  
  [1]  + suspended (tty output)  bin/mp3convert.sh path/a/b &> 
  
  % bg %1
  
  [1]  + continued  bin/mp3convert.sh path/a/b &> 
  
  % jobs
  
  [1]  + suspended (tty output)  bin/mp3convert.sh path/a/b &> 
  
  %

  I can make the script continue, by making it the foreground, but then my terminal is occupied until the script finishes. That means I don’t get the benefit of running the script in the background.

  % 
  
  [1]  + suspended (tty output)  bin/mp3convert.sh path/a/b &> 
  
  % fg %1
  
  [1]  + continued  bin/mp3convert.sh path/a/b &> 
  
  % # much time passes with no activity on terminal, then script finishes
  
  %

  How can I make the script run cleanly in the background ?

  A simplified version of my script is :

  #!/bin/sh
  
  # mp3convert.sh
  
  for f in "$1"/*.flac; do
  
      ffmpeg -i "$f" -c:v copy path/to/dest/"$(basename -s .flac "$f")".mp3
  
  done

  I am running on Mac OS X 10.11.6, with ffmpeg version 3.4 supplied by MacPorts.

  An apparently related question is why do I get “Suspended (tty output)” in one terminal but not in others ?. The answer there is to set the terminal state with stty -tostop. That didn’t help me ; I already had that state set.