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• Use FFMPEG to create video from jpeg, and index using vlc

  16 novembre 2011, par Greg

  OpenSuse 11.4
  FFMEG 0.8.5

  I'm using FFMPEG to create a 5 minute mpeg from about 2100 individual jpegs (7fps). I've been using the following command (OpenSuse 11.4)
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg

  Now I Try to open the file (In windows XP with VLC 1.1.11 Player).
  Media->AdvancedFileOpen
  *I select "Show more options" and set StartTime to 5s. I expect that the video should start 5 seconds in, but instead it starts at a seemingling random (although consistent) time of 30 seconds in.

  I also tried changing ffmpeg command to :
  /usr/bin/ffmpeg -sameq -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg
  *This result in about a constant 2x offset (5sec => 10sec) (10s => 20s) etc. But filesize is also about 6x larger, which is a strain on my storage.

  I also tried
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 -f mpegts Event-3692-r1-s1-3.mpg
  *This result in vlc not indexing at all into my video. Also not desired. Anybody have any clues what is going on here. It is very important for me to be able to use this VLC feature and have it work correctly.

  Thanks in advance

• DirectShow RTSP SourceFilter with MPEG-4 Video Stream

  5 octobre 2011, par 6.45.Vapuru

  I create a simple direct show source filter using FFmpeg.I read rtp packets from RTSP source and give them to decoder. It works for h264 stream.

  MyRtspSourceFilter[H264 Stream] ---> h264 Decoder --> Video Renderer

  The bad news is that it does not work for MPEG-4. I can able to connect my rtsp source filter with MPEG-Decoder. I got no exception but video renderer does not show anything. Actually just show one frame then nothing [just stop]... Decoders and Renderers are 3rd party so i can not debug them.

  MyRtspSourceFilter[MP4 Stream] ---> MPEG-4 Decoder --> Video Renderer

  I can able to get rtp packets from MPEG-4 RTSP Source using FFmpeg sucessfully.There is no problem with it.

  It seems that i have not set something(?) in my Rtsps Source
  Filter which is not necessary for H264 stream but may be important for
  MPEG-4 stream

  What may cause this h264 stream and MPEG-4 stream difference in a direct show rtsp source filter ? Any ideas.

  More Info :

  — First i try some other rtsp source filters for MPEG-4 Stream...Although my rtsp source is same i see different subtypes in their pin connections.

  — Secondly i realy get suspicious if the source is really MPEG-4 SO i check with FFmpeg...FFmpeg gives the source codec id as "CODEC_ID_MPEG4".

  Update :
  [ Hack ]

  I just set m_bmpInfo.biCompression = DWORD('xvid') it just worked fine...But it is static. How to dynamically get/determine this value using ffmpeg or other ways...

• Getting realtime output from ffmpeg to be used in progress bar (PyQt4, stdout)

  8 mars 2017, par Jason O'Neil

  I’ve looked at a number of questions but still can’t quite figure this out. I’m using PyQt, and am hoping to run ffmpeg -i file.mp4 file.avi and get the output as it streams so I can create a progress bar.

  I’ve looked at these questions :
  Can ffmpeg show a progress bar ?
  http://stackoverflow.com/questions/1606795/catching-stdout-in-realtime-from-subprocess

  I’m able to see the output of a rsync command, using this code :

  import subprocess, time, os, sys
  
  
  
  cmd = "rsync -vaz -P source/ dest/"
  
  p, line = True, 'start'
  
  
  
  
  
  p = subprocess.Popen(cmd,
  
                       shell=True,
  
                       bufsize=64,
  
                       stdin=subprocess.PIPE,
  
                       stderr=subprocess.PIPE,
  
                       stdout=subprocess.PIPE)
  
  
  
  for line in p.stdout:
  
      print("OUTPUT>>> " + str(line.rstrip()))
  
      p.stdout.flush()

  But when I change the command to ffmpeg -i file.mp4 file.avi I receive no output. I’m guessing this has something to do with stdout / output buffering, but I’m stuck as to how to read the line that looks like

  frame=   51 fps= 27 q=31.0 Lsize=     769kB time=2.04 bitrate=3092.8kbits/s

  Which I could use to figure out progress.

  Can someone show me an example of how to get this info from ffmpeg into python, with or without the use of PyQt (if possible)

  ---

  EDIT :
  I ended up going with jlp’s solution, my code looked like this :

  #!/usr/bin/python
  
  import pexpect
  
  
  
  cmd = 'ffmpeg -i file.MTS file.avi'
  
  thread = pexpect.spawn(cmd)
  
  print "started %s" % cmd
  
  cpl = thread.compile_pattern_list([
  
      pexpect.EOF,
  
      "frame= *\d+",
  
      '(.+)'
  
  ])
  
  while True:
  
      i = thread.expect_list(cpl, timeout=None)
  
      if i == 0: # EOF
  
          print "the sub process exited"
  
          break
  
      elif i == 1:
  
          frame_number = thread.match.group(0)
  
          print frame_number
  
          thread.close
  
      elif i == 2:
  
          #unknown_line = thread.match.group(0)
  
          #print unknown_line
  
          pass

  Which gives this output :

  started ffmpeg -i file.MTS file.avi
  
  frame=   13
  
  frame=   31
  
  frame=   48
  
  frame=   64
  
  frame=   80
  
  frame=   97
  
  frame=  115
  
  frame=  133
  
  frame=  152
  
  frame=  170
  
  frame=  188
  
  frame=  205
  
  frame=  220
  
  frame=  226
  
  the sub process exited

  Perfect !