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• Executing ffmpeg command using Popen

  21 septembre 2014, par dragonator

  I have a strange problem trying to execute ffmpeg command using Popen.
  I have the following piece of code, which I use for executing an external commands in Python :

  from subprocess import Popen, PIPE
  
  from datetime import datetime
  
  
  
  
  
  class Executor(object):
  
  
  
      @classmethod
  
      def execute(cls, command):
  
          """
  
          Executing a given command and
  
          writing into a log file in cases where errors arise.
  
          """
  
          p = Popen(command, stdin=PIPE, stdout=PIPE, stderr=PIPE)
  
          output, err = p.communicate()
  
          if p.returncode:
  
              with open("failed_commands.log", 'a') as log:
  
                  now = datetime.now()
  
                  log.write('{}/{}/{} , {}:{}:{}\n\n'.format(now.day, now.month,
  
                                                             now.year, now.hour,
  
                                                             now.minute,
  
                                                             now.second))
  
  
  
                  log.write("COMMAND:\n{}\n\n".format(" ".join(command)))
  
                  log.write("OUTPUT:\n{}\n\n".format(output.decode("utf-8")))
  
                  log.write("ERRORS:\n{}\n".format(err.decode("utf-8")))
  
                  log.write('-'*40)
  
                  log.write('\n')
  
  
  
              return ''
  
  
  
          if not output:
  
              output += ' '
  
  
  
          return output

  I’ve tested it with others commands, but when I try to execute ffmpeg command - it fails.
  I’m trying to convert some audio format to mp3 format.
  Here is an example of my command :

  ffmpeg -i "/path/old_song.m4a" "/path/new_song.mp3"

  ...simple as that.When I run it in terminal it works fine, but when I try to execute it using the above function it fails.
  Here is the exact error :

  ----------------------------------------
  
  21/9/2014 , 19:48:50
  
  
  
  COMMAND:
  
  ffmpeg -i "/path/old_song.m4a" "/path/new_song.mp3"
  
  
  
  OUTPUT:
  
  
  
  
  
  ERRORS:
  
  ffmpeg version 2.2.3 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Jun  9 2014 08:01:43 with gcc 4.9.0 (GCC) 20140521 (prerelease)
  
    configuration: --prefix=/usr --disable-debug --disable-static --enable-avisynth --enable-avresample --enable-dxva2 --enable-fontconfig --enable-gnutls --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-pic --enable-postproc --enable-runtime-cpudetect --enable-shared --enable-swresample --enable-vdpau --enable-version3 --enable-x11grab
  
    libavutil      52. 66.100 / 52. 66.100
  
    libavcodec     55. 52.102 / 55. 52.102
  
    libavformat    55. 33.100 / 55. 33.100
  
    libavdevice    55. 10.100 / 55. 10.100
  
    libavfilter     4.  2.100 /  4.  2.100
  
    libavresample   1.  2.  0 /  1.  2.  0
  
    libswscale      2.  5.102 /  2.  5.102
  
    libswresample   0. 18.100 /  0. 18.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  "/path/old_song.m4a": No such file or directory
  
  Conversion failed!
  
  
  
  ----------------------------------------

  ...and as you can think of - the file exists.

  I think there is something in passing the command to Popen.communicate but I don’t know exactly.

  Kind regards,

  Teodor D.
  PS : I’m passing the command to Executor.execute as Python list.

  PSS : Calling the Executor.execute :

  def process_conversion(self):
  
      for song in self.files_to_convert:
  
          current_format = song.rsplit('.', 1)[-1]
  
  
  
          old_file = '"{}{}{}"'.format(self.target_dir, os.sep, song)
  
          new_file = '"{}{}{}"'.format(self.target_dir, os.sep,
  
                                       song.replace(current_format, 'mp3'))
  
  
  
          command = ["ffmpeg", "-i", old_file, new_file]
  
          Executor.execute(command)

• Save MJPEG video stream to a raw file

  6 septembre 2014, par user824963

  I’ve a cheap IP cam, and i need to save the video stream inside a single file.

  i’ve tried to execute the wget command towards the stream’ url and the result was a file with this syntax :

  --object-ipcamera
  
  Content-Type:image/jpeg
  
  Content-Length:8012
  
  
  
  ÿØÿà [JPEG IMAGE CHARACTERS]  ÿÙ
  
  --object-ipcamera
  
  Content-Type:image/jpeg
  
  Content-Length:8012
  
  
  
  ÿØÿàÆÿ [JPEG IMAGE CHARACTERS]  ÿÿÿÙ
  
  --object-ipcamera
  
  Content-Type:image/jpeg
  
  Content-Length:8036

  Since i need to store the video stream, is mp4 a proper format to do that ? What if mp4 file being truncated ?

  I tried with ffmpeg :

  ffmpeg -i http://<auth params="params" local="local" url="url">:99/vieostream.cgi out.mp4
  
  </auth>

  the output was

  [ingenient @ 0x1f51600] Could not find codec parameters for stream 0 (Video: mjpeg): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [ingenient @ 0x1f51600] Estimating duration from bitrate, this may be inaccurate
  
  http://aaa@192.168.0.104:99/vieostream.cgi: could not find codec parameters

  and even setting these parameter to the max allowed value there is still the some output.

  I want also say that if i open the video url using VLC GUI, the video stream immediately comes out, so there is a way to auto-detect the video parameters ?

  Note : my server has a small CPU

• Code library for image processing [on hold]

  1er septembre 2014, par user3928079

  Dear Stack Overflow Users,

  I am looking to create my programming portfolio as a graduate of Kennesaw State University by July 2015, when I graduate. I want to create at least 3 cross platform programs related to video or animation. In the package there will be a program for playing video and music files, a program for converting video and music files, and either a program upscaling video and image files or a program that helps animators create animation like Flipbook Pro. Since Java is cross platform, and Java is the language I’m more comfortable with, I’ll develop the software in Java, unless of course Python is cross platform as well. May you please recommend me some image processing libraries that will help me accomplish the development of these types of software programs. For the upscaling program, an upscaling algorithm from BenVista called S-Spline Max is needed, especially since I want to preserve the detail of the image, because in upscaling, you are unable to gain new information from the original information. What are some good image processing libraries I can use. I know of OpenCV, but what do a lot of programs use, high profile or low profile, like Adobe Premiere Pro or Davinci Resolve. FFMPEG is a good video library, but can it easily accomplish what I need ? What are some others that can help me in my 11 month long quest ?

  Regards,

  Jordan White