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• Using a pipe character | with child_process spawn

  19 avril 2020, par Titan

  I'm running nodejs on a raspberry pi and I want to run a child process to spawn a webcam stream.

  



  Outside of node my command is :

  



  raspivid -n -mm matrix -w 320 -h 240 -fps 18 -g 100 -t 0 -b 5000000 -o - | ffmpeg -y -f h264 -i - -c:v copy -map 0:0 -f flv -rtmp_buffer 100 -rtmp_live live "rtmp://example.com/big/test"


  



  With child_process I have to break each argument up

  



  var args = ["-n", "-mm", "matrix", "-w", "320", "-h", "240", "-fps", "18", "-g", "100", "-t", "0", "-b", "5000000", "-o", "-", "|", "ffmpeg", "-y", "-f", "h264", "-i", "-", "-c:v", "copy", "-map", "0:0", "-f", "flv", "-rtmp_buffer", "100", "-rtmp_live", "live", "rtmp://example.com/big/test"];


  



  camera.proc = child.spawn('raspivid', args);


  



  However it chokes on the | character :

  



  error, exit code 64
Invalid command line option (|)


  



  How do I use this pipe character as an argument ?

  


• ffmpeg mp3 encoding result differs between pipe and file creation

  11 octobre 2018, par Jinsung Lee

  I’m making the program by using ffmpeg but stuck in some problem

  Encode to mp3 and file out

  ffmpeg -nostats -loglevel 0 -i example.weba -i albumart.jpg -map 0:0 -map 1:0 -id3v2_version 3 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (front)" out.mp3

  this works very good but

  Encode to mp3 and pipe out

  ffmpeg -nostats -loglevel 0 -i example.weba -i albumart.jpg -map 0:0 -map 1:0 -id3v2_version 3 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (front)" -f MP3 - > out.mp3

  using pipe output i got

  ffmpeg -i out.mp3
  
  [mp3 @ 0000000001028980] Header missing

  This error

  I need to get this mp3 data with oneline php shell_exec command

  any solution ?

  Thanks

• Proper way to pipe raw video to ffmpeg in c#

  11 octobre 2018, par Wahid Masud

  In my Asp.NET MVC app I’m trying to pipe the video from Request.Files[] to the ffmpeg.exe process. The code produces an output file, but I’m getting a static video, no contents there. And I’m not sure if the problem is in the arguments or in the code.

  var request = System.Web.HttpContext.Current.Request;
  
  var stream = request.Files["upload"].InputStream;
  
  var ffmpeg = System.Web.HttpContext.Current.Server.MapPath("~/FFMpeg/ffmpeg.exe");
  
  var outputDir = System.Web.HttpContext.Current.Server.MapPath("~/Uploads/converted.mp4");
  
  
  
  var inputArgs = "-f rawvideo -pix_fmt rgb32 -video_size 1280x720 -i -";
  
  var outputArgs = "-vcodec libx264 -crf 23 -pix_fmt rgb32 -preset ultrafast " + outputDir;
  
  
  
  var process = new Process
  
  {
  
      StartInfo =
  
      {
  
          FileName = ffmpeg,
  
          Arguments = $"{inputArgs} {outputArgs}",
  
          UseShellExecute = false,
  
          CreateNoWindow = true,
  
          RedirectStandardInput = true
  
      }
  
  };
  
  
  
  process.Start();
  
  
  
  var ffmpegIn = process.StandardInput.BaseStream;
  
  
  
  // Write Data
  
  byte[] buffer = new byte[stream.Length];
  
  stream.Read(buffer, 0, (int)stream.Length);
  
  ffmpegIn.Write(buffer, 0, (int)stream.Length);
  
  
  
  ffmpegIn.Flush();
  
  ffmpegIn.Close();  

  The video size is always 1280x720 but framerate may vary, so I’m not sure if the inputArgs is right. Any suggestions would be appreciated.