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• Speed advantage in combining FFmpeg filters ?

  4 mai 2020, par lach_codes

  I'm currently using five separate FFmpeg processes to do the following :

  



  

  1. trim & crop Vid B

  


  2. scale Vid B to height of Vid A

  


  3. combine Vid B & Vid A

  


  4. add a fade-in/fade-out to Combined Vid

  


  5. add an overlay to fade in/out vid

  


  



  I have them all set to ultrafast but it still takes a long time - about 40 seconds when each video is 10 seconds long.

  



  I initially explored combining some of the filters but couldn't get it working in the timeframe I had available. I also wasn't sure if the time spent figuring out how to combine all the filters would pay off in a faster processing time.

  



  Any thoughts/insights from you brilliant FFmpeg gurus ? Would this speed up processing, and if so, should I combine all the commands together or are there some I should combine and others I should leave separate ?

  



  Here are my current commands, all of which are working :

  



  // trimming 200ms off begining of vid B + cropping frame (note that I have previously retrieved dimensions and duration of both videos with ffprobe)
1. `ffmpeg -i vidB.mov -ss 200 -t ${vidB.duration} -async 1 -filter:v "crop=iw:${vidB.croppedHeight}:0:${vidB.offset}" -preset ultrafast -c:a copy croppedVidB.mov`

// scale Vid B up to Vid A's height
2. `ffmpeg -i croppedVidB.mov -vf scale=-2:${vidA.height} vidBScaled.mov`

// combine videos
3. `ffmpeg -i vidA.mov -i vidBScaled.mov -filter_complex "[0:v][1:v] hstack=inputs=2[v]; [0:a][1:a]amix[a]" -map "[v]" -map "[a]" -preset ultrafast -ac 2 combined.mov`

// add fade in & out
4. `ffmpeg -i combined.mov -sseof -1 -copyts -i combined.mov -filter_complex "[1]fade=out:0:30[t];[0][t]overlay,fade=in:0:30[v]; anullsrc,atrim=0:1[at];[0][at]acrossfade=d=1,afade=d=1[a]" -map "[v]" -map "[a]" -c:v libx264 -crf 22 -preset ultrafast -shortest fadeInOut.mov`

// add overlay
5. `ffmpeg -i fadeInOut.mov -i overlay.png -filter_complex overlay=W-w-10:H-h-10 -codec:a copy -preset ultrafast -async 1 overlay.mov`


  



  Thanks in advance for your thoughts !

  


• How to create thumbnail about torrent without downloading video files ? [on hold]

  1er septembre 2019, par tty78

  Most of time, torrent sites like RARBG/The Pirate Bay/KickAss would return many query results even through I have typed in many detailed keywords, which is not strange because there are many people upload it.

  So, when i want to watch/download a torrent movie, it’s better to check the video first to find out that :

  • is it a fake video
  • is the video watermarked
  • is there some AD in the video
  • is it 1980*1080 or 640*480 ??

  What i want to do is creating thumbnail of the videos without download them, so that i can save a lot of broadband, disk space and time.

  Now I can create thumbnail with a python tool - vcsi, but it depends on the video file stored in disk.
  In fact, vcsi get meta information with ffprobe and create thumbnail using ffmpeg.

  def probe_media(self, path):
  
      """Probe video file using ffprobe
  
      """
  
      ffprobe_command = [
  
          "ffprobe",
  
          "-v", "quiet",
  
          "-print_format", "json",
  
          "-show_format",
  
          "-show_streams",
  
          path
  
      ]
  
  
  
      try:
  
          output = subprocess.check_output(ffprobe_command)
  
          self.ffprobe_dict = json.loads(output.decode("utf-8"))
  
      except FileNotFoundError:
  
          error = "Could not find 'ffprobe' executable. Please make sure ffmpeg/ffprobe is installed and is in your PATH."
  
          error_exit(error)

  ffmpeg_command = [
  
          "ffmpeg",
  
          "-ss", skip_time,
  
          "-i", self.path,
  
          "-ss", skip_delay,
  
          "-vframes", "1",
  
          "-s", "%sx%s" % (width, height),
  
      ]

  WebTorrent may be a solution but it’s not good because I have a lot of torrent file to scan.
  I want to create thumbnail on a ubuntu VPS because it can run day and night, and i can post thumbnail under the torrent comments.
  Some key frame, resolution and duration are enough, maybe.
  

• Révision 18829 : SQLite :

  19 décembre 2011, par cedric -

  implementation erronee de TO_DAYS qui doit compter le nombre de jour depuis 0000-00-00 et non le nombre de jour depuis le debut de l’année. Provoquait l’envoi intempestif du mail de nouveautés

  simplifier la fonction LEAST qui peut s’appuyer sur le min() de (...)