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• When using subprocess passthrough is not accepting both inputs

  30 janvier 2021, par Baraque Obahamas

  Im trying to have two subprocesses pipe into one and output via the passthrough. My goal is to make it possible to download 2 files (one video and one audio) and combine them with ffmpeg.

  


  header('Content-Description: File Transfer');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header("Content-Disposition: attachment; filename=\"ok.mp4\"");
header("Content-Type: application/octet-stream");

$cmd = "<(youtube-dl -f bestvideo[ext=mp4] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) <(youtube-dl -f bestaudio[ext=m4a] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) | ffmpeg -i - -i pipe:3 -movflags frag_keyframe+empty_moov+faststart -frag_duration 3600 -c:v copy -c:a copy -f mp4 -";

$cmd = passthru($cmd, $status);


  


  My error is : -bash : /dev/fd/63 : Permission denied

  


• Compression of a video with constant background

  28 juin 2017, par Spirou003

  (sorry if my english is bad, I can read it but I don’t write it quite well...)

  I want to compress some videos, which have two particularities :

  • there is a background that covers 90% of the area, during the whole video
  • most of the others elements can be separately described by a picture in move

  My videos are like this one, and don’t have audio. As you can see, almost everything can be described only by using a fixed background, few small images in move, plus a noise. Moreover, this noise will be almost nul and then an entropic coding would be very efficient. I think it will produce tiny files (< 5 Mo) even if the duration is in hours, a result that is very appreciable since I have actually recorded 30h of game (actual size is 3 Go).

  Is there any way to get new video files, that benefit of these informations ? If yes, what are the implication of a such encoding for watching these videos with Windows Media Player, or for usage with ffmpeg ?

  I searched with Google after anything that can help me, but I don’t know which keyword I can use for this, then I didn’t found anything usefull :-(

  Thanks in advance :-)

  PS : another example, the video is accelerated but shows the interesting moves

• Increasing speed of a video in C# ?

  13 décembre 2017, par alan samuel

  I am trying to increase the speed of a video using NReco.VideoConverter.FFMpegConverter

  Here is what I have tried.

    var ffMpeg = new NReco.VideoConverter.FFMpegConverter();
  
    string inputfile = @"C:\Users\Alan\Desktop\Video.flv";
  
    string outputfile = @"C:\Users\Alan\Desktop\converted.mp4";
  
  
  
  
  
    ConvertSettings convertSettings = new ConvertSettings
  
          {
  
              MaxDuration = 10,
  
              VideoFrameRate = 12
  
              //VideoFrameCount = 10
  
  
  
          };
  
  
  
  ffMpeg.ConvertMedia(inputfile,Format.flv, outputfile,Format.mp4,convertSettings);

  What I want is like a video with an increased playback like in this example - https://www.youtube.com/watch?v=6tQ1ewhGiwk

  This is what I am basically trying to do.