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• Extract frames and miliseconds

  6 décembre 2013, par Gonzalo Solera

  I would like to be able to extract all the frames of a video and their respectives times. I'm using ffmpeg compiled staticall for android and I'm using this command to extract all the frames of a video :

  ffmpeg -i /inputFile.mp4/ -y /output/%d.jpg

  This works good but I would be very grateful if anyone could show me how to record in an arraylist the time of each frame. (I suppose reading the output when I execute the command) :

  Process p = Runtime.getRuntime().exec(myCommand);

  Thanks for help !!

• Faster way to write image to Process.StandardInput.BaseStream

  4 septembre 2012, par Hasibii

  Im trying to send a lot of desktop captured images to an encoders (FFmpeg) stdin.

  The following code example works.

  the CaptureScreen() function provides an image in 5-10 ms.

  If I save the image in a MemoryStream it takes almost no time.

  But I can only save 1 image every 45 ms to
  proc.StandardInput.BaseStream.

  public void Start(string bitrate, string buffer, string fps, string rtmp, string resolution, string preset)
  
  {
  
      proc.StartInfo.FileName = myPath + "\\ffmpeg.exe";
  
      proc.StartInfo.Arguments = "-f image2pipe -i pipe:.bmp -vcodec libx264 -preset " + preset + " -maxrate " + bitrate + "k -bufsize " +
  
      buffer + "k -bt 10 -r " + fps + " -an -y test.avi"; //+ rtmp;
  
      proc.StartInfo.UseShellExecute = false;
  
      proc.StartInfo.RedirectStandardInput = true;
  
      proc.StartInfo.RedirectStandardOutput = true;
  
  
  
      proc.Start();
  
  
  
      Stopwatch st = new Stopwatch();
  
      BinaryWriter writer = new BinaryWriter(proc.StandardInput.BaseStream);
  
      System.Drawing.Image img;
  
  
  
      st.Reset();
  
      st.Start();
  
  
  
      for (int z = 0; z < 100; z++)
  
      {
  
          img = ScrCap.CaptureScreen();
  
          img.Save(writer.BaseStream, System.Drawing.Imaging.ImageFormat.Bmp);
  
          img.Dispose();
  
      }
  
  
  
      st.Stop();
  
      System.Windows.Forms.MessageBox.Show(st.ElapsedMilliseconds.ToString());
  
  }

  The question is :

  Can I do the saving process faster ?

  I try to get stable 60 fps this way

• run ffmpeg from PHP web script

  18 février 2014, par it6

  I need to manage the recording/capture of a website mindwhile it is running a slide-show to get videos form these slides.

  My approach is :

  <?php 
  
  
  
  define('FFMPEG_LIBRARY', '/usr/bin/ffmpeg ');
  
  
  
  $ffmpegcmd = "ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/output.mpg";
  
  
  
  shell_exec($ffmpegcmd);  
  
  
  
  ?>

  But i get this error from php error log :

  [x11grab @ 0x81e8aa0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 800 height: 600
  
  No protocol specified
  
  No protocol specified
  
  [x11grab @ 0x81e8aa0] Could not open X display.
  
  :0.0: Input/output error

  Similar command from console run good.

  Please, any help to get display and be able to control ffmpeg from browser php script ?

  Thanks in advance.

  ---

  thanks for your time.

  I got rid the X display error, but not I still haven't got the capture.

  Using xvfb I get an unknown file at /tmp written by www-data user :
   rw-r—r— 1 www-data www-data 11252 Sep 12 09:49 server-B20D7FC79C7F597315E3E501AEF10E0D866E8E92.xkm

  Running startx I got also an unknown file at /tmp
   rw------- 1 www-data www-data 59 Sep 12 09:53 serverauth.oLcFlG7tXC

  any of both grow in size so it is not capturing anything. The content is some binary thing.
  What are those files about ?

  What I am trying is to write a script in which I can control the time ffmpeg is capturing the desktop to create a video from a jquery slide displayed on a website.

  My try from console is closer, but if I can do it by browser I will be able to know when to stop sending an AJAX request once the slide is finished.

  This is my try from console :

  #!/bin/bash
  
  
  
  # start the slide website: I will need to change it to control by querystring the language and course level
  
  firefox http://www.languagecourse.net/vocabulary-trainer.php &
  
  # start recording: I will need to adjust the frame to capture
  
  ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/output2.mpg &
  
  # since I can't control the time a course takes I pause an arbitrary time
  
  sleep 5
  
  # look for the capture PID and close it
  
  for i in $(ps aux | grep ffmpeg | sed "s/  */#/g" | cut -f2 -d#)
  
  do
  
    echo "proceso $i killed"
  
    kill -9 $i
  
  done

  I wonder once the website is opened I can continue doing the control from AJAX, but not know if I will be able to get the ffmpeg PID to stop the command.

  I will appreciate any kind of comments.

  Regards,
  ·_-