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• How to implement spring animation (mass, tension, friction) in FFmpeg zoompan filter instead of linear interpolation ?

  29 mai, par Mykyta Manuilenko

  I'm trying to create a zoom-in and zoom-out animation using FFmpeg's zoompan filter, but I want to replace the linear interpolation with a spring animation that uses physics parameters (mass, tension, friction).

  


  My input parameters :

  


  "zoompan": {
  "focusRect": {
    "x": 1086.36,
    "y": 641.87,
    "width": 613,
    "height": 345
  },            
  "easing": {
    "mass": 1,
    "tension": 120,
    "friction": 20
  }
}


  


  Current working linear animation :

  


  ffmpeg -framerate 25 -loop 1 -i input.png \
  -filter_complex "\
    [0:v]scale=6010:3380,setsar=1,split=3[zoomin_input][hold_input][zoomout_input]; \
    [zoomin_input]zoompan= \
      z='iw/(iw/zoom + (ow - iw)/duration)': \
      x='x + (3400 - 0)/duration': \
      y='y + (2009 - 0)/duration': \
      d=25:fps=25:s=1920x1080, \
      trim=duration=1,setpts=PTS-STARTPTS[zoomin]; \
    [hold_input]crop=1920:1080:3400:2009,trim=duration=4,setpts=PTS-STARTPTS[hold]; \
    [zoomout_input]zoompan=\
      zoom='if(eq(on,0),iw/ow,iw/(iw/zoom + (iw-ow)/duration))':\
      x='if(eq(on,0),3400,x + (0-3400)/duration)':\
      y='if(eq(on,0),2009,y + (0-2009)/duration)':\
      d=25:fps=25:s=1920x1080, \
      trim=duration=1,setpts=PTS-STARTPTS[zoomout];
    [zoomin][hold][zoomout]concat=n=3:v=1:a=0[outv]" \
  -map "[outv]" \
  -crf 23 \
  -preset medium \
  -c:v libx264 \
  -pix_fmt yuv420p \
  output.mp4


  


  Notes :

  


  


  • It creates a perfectly straight zoom path to the specific point on the screen (similar to pinch-zooming on a smartphone - straight zooming to the center of the focus rectangle)

    


  


  • To improve the quality of the output, I upscale it beforehand

    


  


  


  What I want to achieve :

  


  Instead of linear interpolation, I want to implement a spring function with these physics parameters :

  


  

  • mass : 1

  


  • tension : 120

  


  • friction : 20

  


  


  Note that these params can be changed.

  


  Also, I want to preserve a perfectly straight zoom path to the specific point on the screen (similar to pinch-zooming on a smartphone).

  


  Question :

  


  How can I properly implement a spring animation function in FFmpeg's zoompan filter ?

  


• Where can I find the ffmpeg binaries for ubuntu ? [on hold]

  26 janvier 2015, par Hazem Taha

  I’m searching for the suitable binary package of the ffmpeg library to use in php using exec command.
  I don’t know which one should I download from this site
  https://www.ffmpeg.org/download.html
  and how to install it.

  Thanks.

• How to run a python code via Django templates ?

  18 novembre 2018, par Iskender Berdiev

  I want to execute code below when the is submitted (project on Django) :

  from os import system, listdir, remove
  
  link = 'https://www.youtube.com/watch?v=ME9yO1KEVoo'
  
  
  
  def download(): ## Downloading a video from YouTube using youtube-dl
  
      system("youtube-dl -o download {}".format(link))
  
  
  
  def convert():  ## Converting downloaded video to mp3 format via ffmpeg.exe(same directory)
  
      listOfFiles = listdir('.')
  
      for i in listOfFiles:
  
          if i.startswith("download"):
  
              name = i
  
              system("ffmpeg -i {} download.mp3".format(name))
  
  
  
  def main():
  
      download()
  
      convert()
  
  
  
  main()

  I have tried to put this code into views.py :

  class download(TemplateView):
  
      def main(request):
  
          if request.method == 'POST':
  
              link = 'https://www.youtube.com/watch?v=ME9yO1KEVoo'
  
              system("youtube-dl -o download {}".format(link))
  
              listOfFiles = listdir('.')
  
              for i in listOfFiles:
  
                  if i.startswith("download"):
  
                      name = i
  
                      system("ffmpeg -i {} download.mp3".format(name))
  
          return redirect ('loader/wait.html')

  urls.py :

  path('wait/', views.download.as_view(), name='wait')

  and the html form which is submitted to run views.download.as_view() :

  <form action="{% url " method="POST">{% csrf_token %}
  
  <input type="submit" value="Yes" />
  
  </form>