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• Extract Images from video and rebuild video with these images

  6 mars 2015, par David Zenou

  I have a very interesting question i think, i did a simple test.

  First step : I extract images from a little video (duration : 1 minute and 4 seconds) :

  ffmpeg -i C:\test\video.mp4 -r 30 -s 640x360 -f image2 C:\test\foo-%05d.jpeg

  Second step : I want to rebuild the initial video with these extracted images with same parameters :

  ffmpeg -f image2 -i C:\test\foo-%05d.jpeg -r 30 -s 640x360 C:\test\final.mp4

  Special result : Initial video (video.mp4) duration was 1 minute and 4 seconds and new video generated (final.mp4) duration is 1 minute and 17 seconds : the new video is longer and the new film seems slightly slower than the initial video.

  My question : Is it possible to get exactly the same film like initial (same duration, same speed) rebuilding the video from its exctrated images ?

• ffmpeg black screen issue for video video generation from a list of frames

  11 mai 2023, par arlaine

  I used a video to generate a list of frames from it, then I wanted to create multiple videos from this list of frames.
I've set starting and ending frames indexes for each "sub video", so for example,
indexes = [[0, 64], [64, 110], [110, 234], [234, 449]], and those indexes will help my code generate 4 videos of various durations. The idea is to decompose the original video into multiple sub videos. My code is working just fine, the video generated.

  


  But every sub video start with multiple seconds of black screen, only the first generated video (so the one using indexes[0] for starting and ending frames) is generated without this black screen part. I've tried changing the frame rate for each sub_video, according to the number of frames and things like that, but I didn't work. You can find my code below

  


  for i, (start_idx, end_idx) in enumerate(self.video_frames_indexes):
    if end_idx - start_idx > 10:
        shape = cv2.imread(f'output/video_reconstitution/{video_name}/final/frame_{start_idx}.jpg').shape
        os.system(f'ffmpeg -r 30 -s {shape[0]}x{shape[1]} -i output/video_reconstitution/{video_name}/final/frame_%d.JPG'
              f' -vf "select=between(n\,{start_idx}\,{end_idx})" -vcodec libx264 -crf 25'
              f' output/video_reconstitution/IMG_7303/sub_videos/serrage_{i}.mp4')


  


  Just the ffmpeg command

  


  ffmpeg -r 30 -s {shape[0]}x{shape[1]} -i output/video_reconstitution/{video_name}/final/frame_%d.JPG -vf "select=between(n\,{start_idx}\,{end_idx})" -vcodec libx264 -crf 25 output/video_reconstitution/IMG_7303/sub_videos/serrage_{i}.mp4


  


• How to use command of ffmpeg on android

  23 janvier 2015, par user2830969

  I download ffmpeg static from http://ffmpeg.gusari.org/static/ and I run command

  ./ffmpeg -i inputFile.mp4 -vf drawtext="fontsize=60:fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:fontcolor=green:text=AAAA:x=(w-max_glyph_w)/2:y=h/2-ascent" outputFile.mp4 

  it work fine on my desktop.
  I want to use this command to run in android. I copy ffmpeg file to my android app to run command but it not work.

  public ProcessRunnable create() {
  
          if (inputPath == null || outputPath == null) {
  
              throw new IllegalStateException("Need an input and output filepath!");
  
          }   
  
  
  
          final List<string> cmd = new LinkedList<string>();
  
           public ProcessRunnable create() {
  
          if (inputPath == null || outputPath == null) {
  
              throw new IllegalStateException("Need an input and output filepath!");
  
          }   
  
  
  
          final List<string> cmd = new LinkedList<string>();
  
  
  
          cmd.add(mFfmpegPath);
  
          cmd.add("-i");
  
          cmd.add(inputPath);
  
          cmd.add("-vf");
  
          cmd.add("drawtext=\"fontsize=60:fontfile=/system/fonts/DroidSans.ttf:fontcolor=green:text=AAAA:x=(w-max_glyph_w)/2:y=h/2-a
  
          cmd.add(mFfmpegPath);
  
          cmd.add("-i");
  
          cmd.add(inputPath);
  
          cmd.add("-vf");
  
          cmd.add("drawtext=\"fontsize=60:fontfile=/system/fonts/DroidSans.ttf:fontcolor=green:text=AAAA:x=(w-max_glyph_w)/2:y=h/2-ascent\"");
  
          cmd.add(outputPath);
  
          Log.w("Command", cmd.toString());
  
          final ProcessBuilder pb = new ProcessBuilder(cmd);
  
          return new ProcessRunnable(pb);
  
      }
  
  </string></string></string></string>

  please tell me know "How can I do that ?" thanks so much