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• Python : Using FFMPEG to create a video using a series of images

  5 février 2019, par VXMH

  I am fairly new to Python and this is my first time using ffmpeg (basing this code on a colleagues).

  I have some code that takes a snapshot of the screen every X seconds and then creates a video out of these files however I am having issues when creating the video. This is my code for generating the video :

  def create_video(screen_resolution, image_location, subfolder, count, preset, qaulity, duplicated_frame, video_path, video_filename):
  
  video_path = path + video_path
  
      {1}\\%d.jpg -vcodec libx264 -preset {2} -crf {3} -r {4} -pix_fmt yuv420p {5}\\{6}.mp4"
  
  proc = subprocess.Popen("C:\\ffmpeg\\ffmpeg.exe -r 1 -f image2 -s %s \
  
                              -pattern_type sequence \
  
                              -start_number 1 \
  
                              -i %s%s\\%s%d.png \
  
                              -vcodec libx264 \
  
                              -preset %s \
  
                              -crf %s \
  
                              -r %s \
  
                              -pix_fmt yuv420p \
  
                              %s\\%s.mp4" %
  
                              (screen_resolution, image_location, subfolder, count, preset[2], qaulity, duplicated_frame, video_path, video_filename), shell = True)

  and the error I am getting is :

  TypeError : %d format : a number is required, not str

  I have tried searching for a solution but not getting anywhere fast. I know the %d is looking for an input from the list at the end but from what I can see this is also the way to tell the FFMPEG to use all files in the image location.

  Hopefully someone can help with this, apologies if this is a duplicate question but as mentioned, I have tried searching, a lot.

• ffmpeg convert a series of images to video - with crossfade or any other transition between every two frames

  29 février 2020, par Narendra Singh

  I am currently able to convert a series of images to video, but I do also need to add transitions / animation in between them.

  String[] ffmpegCommand = {"/data/data/mypackage/app_bin/ffmpeg", "-y",
  
  "-qscale", "1", "-r", "" + framerate, "-i", "/data/data/mypackage/app_ipImg/image%3d.jpg",
  
  "-t", "" + (((total_images) * delay_of_each_frame_in_seconds) + 4), //"-s",heightwidth,
  
  "-vcodec", "libx264", "-s", "640x480",
  
   Environment.getExternalStorageDirectory() + "/photo_directory/myVideo.mp4"};

  The above command is working for me to create video from image series

  But

  Now, I do want to add fade or other transition / animation to be displayed in final video before each of the frames.

  I googled a lot, but didn’t find any solution to this trouble, yet.

  Please suggest me the way.

  Thanks in advance.

• ffmpeg use complex_filter only for a part of the video

  7 mars 2019, par Andy P

  I am trying to apply a filter to only the first few seconds of a video clip - and leave the rest of the video unchanged.

  why ?
  I got some video clips that I wanted to put on a website - unfortunatelly those clips are starting with a black background, which does not fit the website’s design. Therefor I was changing the background to transparent.

  I got that filter working from many of the great answers here (thanks to Gyan) and those videos are playing fine in common browsers :

  ffmpeg -i ${1} -filter_complex "[0]split[m][a];
  
  [a]geq='if(lt(lum(X,Y),16),0,255)',hue=s=0[al];
  
  [m][al]alphamerge,format=yuva420p" -c:v libvpx-vp9 -b:v 0 -crf 18 -an -auto-alt-ref 0 ${1}.webm

  the problem now : of course this replaces all black pixels during the video, which leads to many artefacts later on. Therefor I am searching for a way to apply that filter only to the first 5-ish seconds.

  I think I need a second split and a crop or a trim and a concat filter with a timestamp - but I can’t make it work :(

  ffmpeg -i ${1} -filter_complex "[0]split[f][s];
  
  [f]trim=start=0,duration=5[ft];
  
  [s]trim=start=6[st];
  
  [st]split[m][a];
  
  [a]geq='if(lt(lum(X,Y),16),0,255)',hue=s=0[al];
  
  [m][al]alphamerge,format=yuva420p[mal];
  
  [ft][mal]concat" -c:v libvpx-vp9 -b:v 0 -crf 18 -an -auto-alt-ref 0 ${1}.webm