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• A random pixel on a frame. (ffmpeg)

  4 juin 2013, par Chris Russo

  Hello folks of SO !

  We're trying to do some very small and simple code in PHP to generate a variation of a video, using always the same file.

  The script would have to make a small pixel mark, on random or specific frame of the video file, and this would have to be streamed in real time.

  Here's some pseudo code to explain my idea :

  $frame = $_GET[frame];
  
  $videofile = 'video.avi';
  
  
  
  make_random_red_pixel_mark($videofile, $frame);

  Does anyone know if this is possible using ffmpeg ? As well, it is of extreamly importance for us, to execute this procedure as fast as possible.

  A solution that would imply reprocessing the whole video, won't be useful for our purposes. It should be something like a closed caption, or a quick image / overlay filter that could be applied without an entire video reprocessing. As well, we can't put the overlay using Javascript nor any HTML approach, since the actual manipulation has to be on the video file itself.

  The quality, and framerate of the original video, should be kept intact. Perhaps some other PHP module or software that could be execute from PHP using an exec() ?

  Any recommendation ?

  Thanks in advance !!
  Chris C. Russo

• avi encoded to streaming mp4 or webmnot playing in html5 player

  30 mai 2013, par Vprnl

  [EDIT]

  I'm trying to get ffmpeg to encode various AVI files to mp4 for streaming purposes

  I use this nodejs to start FFMPEG.

  When I try this (webm) (some settings are wrapped by the node module but produce the default FFMPEG command) with this command :

          .withVideoCodec('libvpx')
  
          .addOptions(['-bf 8','-bt 240k','-preset fast','-strict -2','-b:v 320K','-bufsize 62000', '-maxrate 620k','-movflags +empty_moov','-y'])
  
          .withAudioBitrate('192k')
  
          .withAudioCodec('libvorbis')
  
          .toFormat('webm')

  The video get's streamed properly to the client but the duration isn't passed on. So the video has a duration of 'infinite'.

  So I tried to encode with H264. Which also works (I see the duration being set in the client) but no picture sadly.

  For H264 I use :

     .addOptions(['-y','-vcodec libx264','-bf 8','-bt 240k','-preset fast','-strict -2','-b:v 320K','-bufsize 62000', '-maxrate 620k','-acodec aac','-ab 128k','-movflags +empty_moov'])
  
     .toFormat('mp4')

  I get this log :

  

  I hope someone can point me in the right direction. Thanks !

  The client just gives an undefined error.
  I hope someone can point me in the right direction.

  Thanks

• Running cmd in python (ffmpeg)

  29 mars 2017, par Coolcrab

  Atm I have this as my code, the first line seems to work well but the 2nd gives errrors.

  os.chdir('C://Users/Alex/Dropbox/code stuff/test')
  
  subprocess.call(['ffmpeg', '-i', 'test%d0.png', 'output.avi'])

  error :

  Traceback (most recent call last):
  
    File "C:\Users\Alex\Dropbox\code stuff\solarsystem.py", line 56, in <module>
  
      subprocess.call(['ffmpeg', '-i', 'test%d0.png', 'output.avi'])
  
    File "C:\Python27\lib\subprocess.py", line 524, in call
  
      return Popen(*popenargs, **kwargs).wait()
  
    File "C:\Python27\lib\subprocess.py", line 711, in __init__
  
      errread, errwrite)
  
    File "C:\Python27\lib\subprocess.py", line 948, in _execute_child
  
      startupinfo)
  
  WindowsError: [Error 2] The system cannot find the file specified
  
  </module>