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• Make gif (ffmpeg) using MOST RECENT 7 jpg files in a directory

  16 juillet 2019, par Brad Sullivan

  I have a bash script which runs on a cron, to take screenshots of my cctv 1x per day to do an annual timelapse. It all works, and I get a YTD sofar.gif of the very first screenshot to the very last screenshot — which is now quite long. I wanted to add a line to make last7days.gif so I could get a shorter weekly gif etc.

  I have searched this site and the web and can list the newest 7 files in terminal using : ls -1t | head -n 9 | tail -n 7 (this removes the .gif and .mov which are modified last) but I do not know how to make that vertical list of 7 filenames into a variable to make a gif using those file names

  # runs from a cronjob. saves live screenshot from CCTV to jpg, then updates the year-to-date movie
  
  
  
  if [ $# -ne 1 ]
  
  then
  
    echo "Usage: `basename $0` OUTDIR"
  
    exit 65
  
  fi
  
  
  
  doexit=0
  
  
  
  start=$(date +%s)
  
  end=$(date +%s)
  
  
  
  outdir=${1%/}
  
  mkdir $outdir
  
  echo "Capturing image..."
  
  
  
  counter=$(date +"%Y_%m_%d_%H-%M-%S");
  
  file=$outdir/$counter.jpg
  
  
  
  if response=$(curl --silent --write-out %{http_code} --max-time 600 'URL REDACTED' -o $file) ; then
  
      echo "Captured & saved $file!"
  
  else
  
      echo "Failed to capture $file"
  
  fi
  
  
  
  ffmpeg -hide_banner -loglevel panic -pattern_type glob -i $outdir/'*.jpg' $outdir/sofar.mov -y
  
  ffmpeg -hide_banner -loglevel panic -pattern_type glob -i $outdir/'*.jpg' $outdir/sofar.gif -y
  
  
  
  exit 1

  Currently, the last lines create a .gif using every image file, this works only because they are saved with the date in the filename.

  I want to add a line to create a .gif using just the most 7 recent images

• How can I change a video frame rate with FFmpeg keeping the same total number of frames ?

  28 mai 2017, par Nuno

  I’ve been searching for an answer here on Stack Overflow and googling everywhere... even though it seems like it should be a very simple command line to me, I just can’t find an answer anywhere.

  I would like to change the frame rate of a video from 23.976fps to 24fps with FFmpeg, lossless and keeping the total number of frames.

  To make it simpler :

  Let’s say I have a 25fps video with a total lenght of 100 frames.

  How can I change it’s frame rate to 50fps, with FFmpeg, lossless and keeping the same total lenght of 100 frames ?

  This was so far the best solution I came across with (which can be found here) :

  Extract the frames as rawvideo :

  ffmpeg -i input.mov -f rawvideo -b 50000000 -pix_fmt yuv420p -vcodec
  rawvideo -s 1920x1080 -y temp.raw

  Recreate the video with new framerate :

  ffmpeg -f rawvideo -b 50000000 -pix_fmt yuv420p -r 24 -s 1920x1080 -i
  temp.raw -y output.mov

  Note 1 : I had to remove "-b 50000000" when recreating the video with the new frame rate, in order to get it to work properly.

  It did exactly what I intended it to do, but I’m still wondering if there is any simpler way to do this ? I’ve tried to pipe them together in one line only, as suggested in the same post, but couldn’t get it to work.

  Note 2 : Even though it does exactly what I wanted it to do, I’ve just later realized there is quality loss using this method, which I would prefer to avoid.

  Thanks everyone in advance !

• Cut multiple parts of a video with ffmpeg

  11 juin 2020, par Mike Baum

  In what I'm trying to do, I need to remove some parts of a video file, and create a new one from that.

  



  For example, from a video file like this :

  



  ===================


  



  I make two cuts

  



  ======||=====||||==


  



  and generate a new smaller video file :

  



  =============


  



  And when I say 2, I mean an arbitrary number of separate cuts, depending on the video file.

  



  If I wanted to cut just one part I would do :

  



  ffmpeg -i video.mp4 -ss 00:00:03.500 -to 00:00:08.500 -async 1 cut.mp4 -y


  



  Which works perfectly. I could perhaps do this many times and then join all the cuts together... But this is very inefficient for larger video files.

  



  To make two cuts I was looking at filter_complex. I've been trying to get it right for hours but I can't seem to get this working :/

  



  If I do something like this I get a video with no audio :

  



  command='ffmpeg -i video.mp4
                -filter_complex "[0]trim=start_frame=10:end_frame=20[v0];
                                 [0]trim=start_frame=30:end_frame=40[v1];
                                 [v0][v1]concat=n=2[v5]"
                -map [v5] -async 1 output.mp4'


  



  If I try to do this, things get all messed up :

  



  ffmpeg -y -i video.mp4 
       -filter_complex "[0:v]trim=start_frame=10:end_frame=20[v0];
                        [0:a]atrim=start=10:end=20[a0];
                        [0:v]trim=start_frame=30:end_frame=40[v1];
                        [0:a]atrim=start=30:end=40[a1];
                        [v0][a0][v1][a1]concat=2:v=1:a=1[v5][a]" \
       -map [v5] -map [a] -async 1 output.mp4


  



  I even trying to to this in Python with ffmpeg-python https://github.com/kkroening/ffmpeg-python but I also can't get audio to work.

  



  Can anyone give me some help on this ?
Thank you very much !!