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• Understanding ffmpeg -benchmark results

  6 septembre 2022, par Ivy Growing

  Adding -benchmark flag to ffmpeg command resutls with addition of following 2 lines in the shell output :

  


  bench: utime=10.125s stime=4.234s rtime=5.606s
bench: maxrss=110080kB


  


  The maxrss serves to indicate the maximum RAM used during the ffmpeg execution. The utime, stime, rtime indicate accordingly :

  


  

  • user time ;

  


  • system time ;

  


  • real time.

  


  


  I tried to understand the meaning of these times from the source code and failed. Please, help.

  


  

  1. Which of these times indicate how much time was human waiting while the ffpmeg was processing the video ?

  


  2. Can this time be seen directly or it's a combination/calculation of these 3 parameters ?

  


  3. How it can be for certain videos utime > rtime and for others utime < rtime ?

  


  


• Issues grabbing frames from an mp4 video using ffmpeg on java

  31 mars 2015, par TamirW

  I am trying to grab a few frames from an mp4 video files using the ffmpeg library (java). Code snippet below.
  The issues I’m facing are :

  • In some (but not all) the videos I’m testing, I am getting the following warning when grabbing the frames : [swscaler @ 0x7fa642a53600] bad src image pointers
  • Sometimes, the frames I get are just blanks (black), sometimes they contain the last frame in the video (meaning that ALL the frames show the same image). Interestingly, when I’m not getting the above warning, the frames are just fine.

  Any clue or direction about how to debug/solve this issue would be greatly appreciated.

      FFmpegFrameGrabber g = new FFmpegFrameGrabber(video);
  
      List<bufferedimage> frames = new ArrayList<bufferedimage>();
  
      try {
  
          g.start();
  
  
  
          int i = 1, noOfFrames = g.getLengthInFrames();
  
          long FR = Math.round(g.getFrameRate());
  
  
  
          while (i &lt; noOfFrames) {
  
              g.setFrameNumber(i);
  
              IplImage img = g.grab();
  
              BufferedImage bimg = img.getBufferedImage();
  
              frames.add(bimg);
  
  
  
              i += FR;
  
          }
  
  </bufferedimage></bufferedimage>

• Next drawtext clears the previous one ffmpeg

  27 août 2021, par Макс Шульдинер

  ffmpeg.exe -i ffmpeg_inputs/zheltiy_chelik.mp4  -vf "[in]drawtext=fonts/Temporarium.otf:text='r':fontcolor=orange:fontsize=100:x=(w-text_w)/2+0:y=0:enable='between(t,0, 11)', drawtext =fonts/Temporarium.otf:text = 'r':fontcolor=orange:fontsize=100:x=(w-text_w)/2+20:y=0:enable='between(t,11, 22)', drawtext =fonts/Temporarium.otf:text = 'r':fontcolor=orange:fontsize=100:x=(w-text_w)/2+40:y=0:enable='between(t,22, 33)'[out]" ffmpeg_outputs/test2.mp4 -y 


  


  There is such a ffmpeg line. Its meaning is to draw a letter 20 pixels to the right of the current position of the word every 11 seconds, and in this way "write the word". But here's the problem - when the second letter starts to render, it overwrites the first, and the third, respectively, overwrites the second. The string seems to have prescribed [in] and [out] but does not help, maybe someone has ideas