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• Find video resolution and video duration of remote mediafile

  22 février 2012, par osgx

  I want to write an program which can find some metainformation of mediafile. I'm interested in popular video formats, such as avi, mkv, mp4, mov (may be other popular too). I want basically to get :

  • Video size (720, 1080, 360 etc)
  • Total runtime of video (may be not very exact)
  • Number of audio streams
  • Name of video codec
  • Name of audio codec

  There is already the mediainfo, but in my program I want to get information about remote file, which may be accessed via ftp, http, samba ; or even torrent (there are some torrent solutions, which allows to read not-yet downloaded file).

  MediaInfo library have no support of samba (smb ://) and mkv format (for runtime).

  Also, I want to know, how much data should be downloaded to get this information. I want not to download full videofile because I have no enough disk space.

  Is this information in the first 1 or 10 or 100 KiloBytes of the file ? Is it at predictable offset if I know the container name and total file size ?

  PS : Platform is Linux, Language is C/C++

• How can I use my exe in a new Process() call ?

  24 février 2017, par looksgoodhoss

  I am working on a project where I create a 10 second sample from a video. To do this, I am using FFMPEG. I would like for the user to upload their own video where the sampling will then take place. The processing will be done in an Azure worker-role and that is where my problem lies.

  If I execute the following command (excuse the absolute paths, they’re my next problem) in Command Prompt then the sampling is completed successfully.

  ffmpeg -t 10 -i C:\Users\looksgoodhoss\Documents\Videos\video.mp4 -map_metadata 0 -acodec copy C:\Users\looksgoodhoss\Documents\Videos\vid.mp4 -y

  I am trying to bring this command into my Visual Studio project via a new Process() call. The video.mp4 and vid.mp4 are trivial names to test and work out my bug.

  bool success = false;
  
              string EXEArguements = @"ffmpeg -t 10 -i C:\Users\looksgoodhoss\Documents\Videos\video.mp4 -map_metadata 0 -acodec copy C:\Users\looksgoodhoss\Documents\Videos\vid.mp4 -y";
  
              string EXEPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot") + @"\", @"approot\ffmpeg.exe");
  
  
  
              try
  
              {
  
                  Process proc = new Process();
  
                  //proc.StartInfo.FileName = @"C:\FFMPEG\bin\ffmpeg";
  
                  proc.StartInfo.FileName = EXEPath;
  
                  proc.StartInfo.Arguments = EXEArguements;
  
                  proc.StartInfo.CreateNoWindow = true;
  
                  proc.StartInfo.UseShellExecute = false;
  
                  proc.StartInfo.ErrorDialog = false;
  
  
  
                  Trace.TraceInformation("FFMPEG completed."); // is shown in log
  
  
  
                  proc.Start();
  
                  proc.WaitForExit();
  
                  success = true;
  
              }
  
              catch (Exception e)
  
              {
  
                  throw;
  
              }
  
              return success;

  The message "FFMPEG completed" is shown in the Compute Emulator UI and so I know that this block of code is executing, however, they’re is no sample video created despite the command being the same.

  Am I executing FFMPEG incorrectly in my Visual Studio project ? I think this is my problem because the same command can successfully be performed through Command Prompt.

  Any help or advice would be greatly appreciated,

  Thanks.

• saving ffmpeg output in a file field in django using tempfiles

  27 janvier 2017, par StarLord

  I am trying to extract audio from video when uploaded, and store it in a different model.

  this is the task code :

  def set_metadata(input_file, video_id):
  
      """
  
      Takes the file path and video id, sets the metadata and audio
  
      :param input_file: file url or file path
  
      :param video_id: video id of the file
  
      :return: True
  
      """
  
      # extract metadata
  
      command = [FFPROBE_BIN,
  
                 '-v', 'quiet',
  
                 '-print_format', 'json',
  
                 '-show_format',
  
                 '-show_streams',
  
                 '-select_streams', 'v:0',
  
                 input_file]
  
      output = sp.check_output(command)
  
      output = output.decode('utf-8')
  
      metadata_output = json.loads(output)
  
      video_instance = Video.objects.get(pk=video_id)
  
      stream = metadata_output['streams'][0]
  
      tot_frames_junk = int(stream['avg_frame_rate'].split("/")[0])
  
      tot_time_junk = int(stream['avg_frame_rate'].split("/")[1])
  
      # update the video model with newly acquired metadata
  
      video_instance.width = stream['width']
  
      video_instance.height = stream['height']
  
      video_instance.frame_rate = tot_frames_junk/tot_time_junk
  
      video_instance.duration = stream['duration']
  
      video_instance.total_frames = stream['nb_frames']
  
      video_instance.video_codec = stream['codec_name']
  
      video_instance.save()
  
  
  
      # extract audio
  
      tmpfile = temp.NamedTemporaryFile(suffix='.mp2')
  
      command = ['ffmpeg',
  
                 '-y',
  
                 '-i', input_file,
  
                 '-loglevel', 'quiet',
  
                 '-acodec', 'copy',
  
                 tmpfile.name]
  
      sp.check_output(command)
  
      audio_obj = Audio.objects.create(title='awesome', audio=tmpfile)
  
      audio_obj.save()

  I am passing video object id and the file path to the method. The file path is a url from azure storage.

  The part where I am processing for metadata, it works and the video object gets updated. But the audio model is not created.

  It throws this error :

  AttributeError("'_io.BufferedRandom' object has no attribute '_committed'",)

  at command :

  audio_obj = Audio.objects.create(title='awesome', audio=tmpfile)

  What am I doing wrong with the temp file.