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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)

• Youtube-dl convert to MP3 multi cores [on hold]

  1er janvier 2017, par Top Games a-Z

  Do you know how to tell to youtube-dl to use all cpu cores when convert music (using ffmpeg) to mp3 ? Because it downloads the song but when it has to convert it uses just one core. Thank you.

• FFMPEG YouTube Live Too Fast

  6 avril 2017, par Liam Martens

  So I am streaming video and audio to YouTube as follows

  THE CONTEXT

  1. First I convert a graphic GIF to an MP4 file

  ffmpeg -f gif -i graphic.gif -c:v libx264 -pix_fmt yuv420p -vf scale=1280:-1 temp.mp4

  2. Then I overlay a PNG with text over the MP4

  ffmpeg -i temp.mp4 -i overlay.png -filter_complex "overlay=10:10" '.$graphicsPath.'/graphic.mp4

  3. Then I start the stream the video and combine it with audio using following code (sources.txt is just a concat list *)

  ffmpeg -f concat -i sources.txt -i music.mp3 \
  
      -c:v libx264 -c:a aac -shortest -deinterlace \
  
      -pix_fmt yuv420p -preset '.$encoding.' -r 30 -g 60 -b:v 2500k \
  
      -acodec libmp3lame -ar 44100 -threads 6 -qscale 3 -b:a 712000 \
  
      -maxrate 800k -bufsize 1400k \
  
      -f flv rtmp://a.rtmp.youtube.com/live2/KEY

  4. After the stream ends, the code starts over again with a new song to mimic a 247 stream.

  THE ISSUE

  So the issue I am having is that it appears to be streaming too fast. It’s like the opposite of buffering issues where the buffer is way too long (as in a full song buffered by the time the first one has finished if you open the stream)

  Does anyone know how I could throttle the output ? I have tried with maxrate and bufsize but no real result.

  * sources.txt example
  file ’graphic.mp4’
  file ’graphic.mp4’
  file ’graphic.mp4’
  file ’graphic.mp4’
  file ’graphic.mp4’
  file ’graphic.mp4’
  and so on