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• ffmpeg, stretch audio to x seconds

  7 janvier, par Max Doumit

  I am trying to make an audio file be exactly x second.

  


  So far i tried using the atempo filter by doing the following calculation

  


  Audio length / desired length = atempo.

  


  But this is not accurate, and I am having to tweak the tempo manually to get it to an exact fit.

  


  Are there any other solutions to get this work ? Or am I doing this incorrectly ?

  


  My original file is a wav file, and my output in an mp3

  


  Here is a sample command

  


  ffmpeg -i input.wav -codec:a libmp3lame -filter:a "atempo=0.9992323" -b:a 320K output.mp3


  


  UPDATE :

  


  I was able to correctly calculate the tempo by changing the way I am receiving the audio length.

  


  I am now calculating the current audio length using the actual file size and the sample rate.

  


  Audio Length = file size / (sample rate * 2)


  


  Sample rate is something like 16000 Hz. You can get that by using ffprob or ffmpeg.

  


• Run 2 exec command in for loop with time interval of 30 seconds using TCL and FFMPEG

  29 novembre 2017, par M. D. P

  i want to Run 2 exec command in for loop with time interval of 30 seconds using TCL and FFMPEG

  my exec command for image is :

  exec ffmpeg -f dshow -benchmark -i video="Integrated Webcam" -s 1280x720 c:/test/sample_image%d.jpg

  my exec command for video is :

  exec ffmpeg -f dshow -benchmark -i video="Integrated Webcam" -s 1280x720 c:/test/sample_video%d.avi

  i want my code to be like this :

  proc a {} { 
  
  
  
  set a 1
  
  
  
  while {$a < 10} {
  
  
  
  after 3000
  
  
  
  exec ffmpeg -f dshow -benchmark -i "video=Integrated Webcam" -s 1280x720 c:/test/sample_image.avi
  
  
  
  after 3000
  
  
  
  exec ffmpeg -f dshow -t 00:00:30 -benchmark -i "video=Integrated Webcam" -s 1280x720 c:/test/sample_video.avi
  
  
  
  incr a
  
  
  
  }
  
  
  
  }
  
  a

  problem here is, after completion of first exec command, it stops its execution. that is it captures the image and stops its execution.

  I also want that this process of capturing image and video should work in loop (while or foreach).

  i have my present working code which execute only one exec command, that to only one. so i want this two exec command to run after one another in loop.

  error report for above program :

  % source c:/other/a/d.tcl
  
  
  
  ffmpeg version N-89212-ga60b2425c3 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  
    libavutil      56.  2.100 / 56.  2.100
  
    libavcodec     58.  3.105 / 58.  3.105
  
    libavformat    58.  2.102 / 58.  2.102
  
    libavdevice    58.  0.100 / 58.  0.100
  
    libavfilter     7.  2.102 /  7.  2.102
  
    libswscale      5.  0.101 /  5.  0.101
  
    libswresample   3.  0.101 /  3.  0.101
  
    libpostproc    55.  0.100 / 55.  0.100
  
  Input #0, dshow, from 'video=Logitech HD Webcam C525':
  
    Duration: N/A, start: 90055.057000, bitrate: N/A
  
      Stream #0:0: Video: rawvideo, bgr24, 1280x720, 30 fps, 30 tbr, 10000k tbn, 10000k tbc
  
  File 'c:/test/sample_20171128_111245.jpg' already exists. Overwrite ? [y/N] [dshow @ 052d4ac0] real-time buffer [Logitech HD Webcam C525] [video input] too full or near too full (181% of size: 3041280 [rtbufsize parameter])! frame dropped!
  
      Last message repeated 886 times
  
  Not overwriting - exiting
  
  bench: maxrss=50856kB
  
  [dshow @ 052d4ac0] real-time buffer [Logitech HD Webcam C525] [video input] too full or near too full (181% of size: 3041280 [rtbufsize parameter])! frame dropped!
  
      Last message repeated 1 times
  
  %

  please provide me the code as answer which will work for above problem.

• Python - check subprocess activity every n seconds

  22 novembre 2017, par hlabor

  I’m trying to make python script (currently on windows) which will open some sub-processes (which will run infinitely) and script should periodically check do all of opened sub-processes still work correctly. So it should be done with while loop, I guess.

  The sub-processes are about FFMPEG livestreaming.

  The problem is when I do time.sleep(n) in my loop, because then every FFMPEG livestream stops, so I suppose time.sleep affect on all of child subprocesses.

  I have no idea how to make it work.

  Here is my python code :

  import os, time, sys, datetime, smtplib, configparser, logging, subprocess, psutil
  
  import subprocess
  
  
  
  def forwardudpstream(channel_number, ip_input, ip_output):
  
      try:
  
          ffmpeg_command = 'ffmpeg -i udp://' + ip_input + ' -vcodec copy -acodec copy -f mpegts "udp://' + ip_output + '?pkt_size=1316"'
  
          ffmpeg_output = subprocess.Popen(ffmpeg_command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=False)
  
          return str(ffmpeg_output.pid)
  
      except:
  
          print ("Exception!")
  
          return '0'
  
  
  
  while True:
  
      configuration = 'config.ini'
  
      channel_list_file = 'CHANNEL_LIST.conf'
  
      pid_folder = "D:\\Forward_UDP_Stream\\pids\\"
  
      channel_list = [line.rstrip('\n') for line in open(channel_list_file)]
  
      for line in channel_list:
  
          if not line.startswith('#') and ('|' in line):
  
              channel_number, ip_input, ip_output = line.split('|')
  
              print('----------')
  
              print("Channel number = ", channel_number)
  
              print("IP Input = ", ip_input)
  
              print("IP Output = ", ip_output)
  
              pid_file_found = False
  
              print("Checking if pid file exists...")
  
              for pidfile in os.listdir(pid_folder):
  
                  if pidfile.startswith(channel_number + '-'):
  
                      print("Pid file is found for this channel.")
  
                      pid_file_found = True
  
                      pid = int(pidfile.split('-')[1].split('.')[0])
  
                      print("PID = ", str(pid))
  
                      print("Checking if corresponding process is active...")
  
                      if not psutil.pid_exists(pid):
  
                          print("Process is not active.")
  
                          print("Removing old pid file.")
  
                          os.remove(pid_folder + pidfile)
  
                          print("Starting a new process...")
  
                          pid_filename = channel_number + '-' + forwardudpstream(channel_number, ip_input, ip_output) + '.pid'
  
                          pid_file = open(pid_folder + pid_filename, "a")
  
                          pid_file.write("Process is running.")
  
                          pid_file.close()
  
                      else:
  
                          print("Process is active!")
  
                      break
  
              if pid_file_found == False:
  
                  print("Pid file is not found. Starting a new process and creating pid file...")
  
                  pid_filename = channel_number + '-' + forwardudpstream(channel_number, ip_input, ip_output) + '.pid'
  
                  pid_file = open(pid_folder + pid_filename, "a")
  
                  pid_file.write("Process is running.")
  
                  pid_file.close()
  
              time.sleep(10)

  Here is my CHANNEL_LIST.conf file example :

  1|239.1.1.1:10000|239.1.1.2:10000
  
  2|239.1.1.3:10000|239.1.1.4:10000

  Perhaps there is some other solution to put waiting and sub-processes to work together. Does anyone have an idea ?

  UPDATE :
  I finally make it work when I removed stdout=subprocess.PIPE part from the subprocess command.
  Now it looks like this :

  ffmpeg_output = subprocess.Popen(ffmpeg_command, stderr=subprocess.STDOUT, shell=False)

  So now I’m confused why previous command was making a problem...?
  Any explanation ?