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• ffmpeg in the use of libardrone by python

  13 mai 2016, par Chao Wang

  Recently I am trying to do a vision-based control using AR.drone 2.0. I meet a problem in the first step that is to import video seen from drone to my PC. I searched online and there is a library called libardrone. I tried to used it but when I do the first step that is to intialize. I wrote

  drone = libardrone.libardrone.ARDrone(True)

  The problem rises in the installation of ffmpeg. I actually installed and set ffmpeg\bin in my path, but I don’t know why it keeps jumping out this error

  The error turns out to be

  Traceback (most recent call last) :

  File "C:\Python27\dronetest.py", line 7, in <module>
  
      drone=libardrone.ARDrone(is_ar_drone_2=True,hd=True)
  
    File "C:\Python27\lib\site-packages\libardrone\libardrone.py", line 126, in __init__
  
      self.network_process = arnetwork.ARDroneNetworkProcess(com_pipe_other, is_ar_drone_2, self)
  
    File "C:\Python27\lib\site-packages\libardrone\arnetwork.py", line 45, in __init__
  
      self.ar2video = ar2video.ARVideo2(self._drone, libardrone.DEBUG)
  
    File "C:\Python27\lib\site-packages\libardrone\ar2video.py", line 37, in __init__
  
      self.h264 = h264decoder.H264Decoder(self, drone.image_shape)
  
    File "C:\Python27\lib\site-packages\libardrone\h264decoder.py", line 82, in __init__
  
      raise Exception("You need to install ffmpeg to be able to run ardrone")
  
  Exception: You need to install ffmpeg to be able to run ardrone
  
  </module>

  The related code in h264decoder.py is

   if (H264Decoder.which('ffmpeg') is None):
  
                      raise Exception("You need to install ffmpeg to be able to run ardrone")
  
  
  
  ....
  
  
  
  
  
  def which(program):
  
          def is_exe(fpath):
  
              return os.path.isfile(fpath) and os.access(fpath, os.X_OK)
  
  
  
          fpath, fname = os.path.split(program)
  
          if fpath:
  
              if is_exe(program):
  
                  return program
  
          else:
  
              for path in os.environ["PATH"].split(os.pathsep):
  
                  path = path.strip('"')
  
                  exe_file = os.path.join(path, program)
  
                  if is_exe(exe_file):
  
                      return exe_file
  
  
  
          return None

• Converting DAV to MP4 and OGG

  27 mars 2015, par mackowiakp

  I want to prepare WEB page containing films from security camera recorders. Each recorder transmit video files in DAV format so each film is converted to MP4 format by script, using such syntax :

  ffmpeg -y -i movie.dav -vcodec libx264 -crf 24 movie.mp4

  So I included in HTMLv5 code such entry :

   <video width="320" height="240">
  
    <source src="movie.mp4" type="video/mp4">
  
  </source></video> 

  It works correctly with Chrome but not with Firefox. For proper work in FF it is necessary add link to OGG file. So correct HTMLv5 syntax for both browsers should look like this :

   <video width="320" height="240">
  
    <source src="movie.mp4" type="video/mp4">
  
    <source src="movie.ogg" type="video/ogg">
  
  </source></source></video>

  Can anybody help me to pass correct ffmpeg syntax to create OGG file ?

  Output from console after using -movflags +faststart options

  [maciek@piotr MMM]$ ../ffmpeg-2.4.2-64bit-static/ffmpeg -movflags +faststart -y -i   04.24.23-04.24.38\[M\]\[@0\]\[0\].dav -vcodec libx264 -crf 24 10.mp4
  
  ffmpeg version 2.4.2-   http://johnvansickle.com/ffmpeg/    Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Oct  9 2014 07:24:56 with gcc 4.8 (Debian 4.8.3-11)
  
    configuration: --enable-gpl --enable-version3 --disable-shared --disable-debug --enable-runtime-cpudetect --enable-libmp3lame --enable-libx264 --enable-libx265 --enable- libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg --enable-libopus --disable-ffserver --enable-libass --enable-gnutls --cc=gcc-4.8
  
    libavutil      54.  7.100 / 54.  7.100
  
    libavcodec     56.  1.100 / 56.  1.100
  
    libavformat    56.  4.101 / 56.  4.101
  
    libavdevice    56.  0.100 / 56.  0.100
  
    libavfilter     5.  1.100 /  5.  1.100
  
    libswscale      3.  0.100 /  3.  0.100
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  0.100 / 53.  0.100
  
  Option movflags not found.

• Scaling and stacking 2 videos

  31 octobre 2019, par Gambit2007

  I have 2 inputs and I want to scale, crop and put them on top of each other at the same time. My command should look something like this :

  ffmpeg -i input1 -i input2 -filter_complex crop=10000:5000:1000:0,scale=3840:1536 vstack output.mp4

  I know I need to use chaining (?) but I tried to look it up online and couldn’t really get it to work.

  So what would be the correct syntax the scale and crop both inputs and then put them vertically on top of each other while using ’-filter_complex’ only once ?