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• Process takes more time to complete in successive iterations

  31 mai 2020, par user1306470

  I have the following code and I'm noticing that the process takes more time to do its thing in each iteration. The line myProcess.StandardOutput.BaseStream.CopyTo(stream); takes around 200ms in the first iteration and in the 500th iteration it takes 3000ms. I'm assuming this line awaits untils there's something in the output buffer to read from, so it follows that myProcess takes increasingly more time to push data to the output stream in every iteration, why does this happen ? How can I fix this ?

  



  while(i<1000){
   using (Process myProcess = new Process())
   {
      myProcess.StartInfo.UseShellExecute = false;
      myProcess.StartInfo.FileName = @"C:\Program Files\ffmpeg\bin\ffmpeg.exe";
      myProcess.StartInfo.CreateNoWindow = true;
      myProcess.StartInfo.WorkingDirectory = @"C:\Program Files\ffmpeg\bin";
      myProcess.StartInfo.Arguments = $@"-i fileName -map 0:a -f mp3 pipe:";
      myProcess.StartInfo.RedirectStandardOutput = true;
      myProcess.StartInfo.UseShellExecute = false;

      myProcess.Start();                           

      myProcess.StandardOutput.BaseStream.CopyTo(stream);        
   }
}


  


• Setting UseShellExecute = false doesn't work in Process.Start

  5 décembre 2015, par Alex Jolig

  There’s a good Q&A about hiding shell execute when running a process which led me to write my own code using ffmpeg :

  Process proc = new Process();
  
  proc.StartInfo.FileName = "ffmpeg";
  
  proc.StartInfo.Arguments = string.Format("-ss {0} -i \"{1}\" -t {2}{3} DB\\Media\\{4}{5} -y",
  
       TimeSpan.Parse(row.Cells["StartdgvList"].Value.ToString()),
  
       openFileDialog.FileName, _durationTime, quality, newTmpSound,
  
       GetExtension(openFileDialog.FileName));
  
  proc.StartInfo.RedirectStandardError = true;
  
  proc.StartInfo.UseShellExecute = false;
  
  proc.StartInfo.CreateNoWindow = true;
  
  if (!proc.Start()) return;
  
  StreamReader reader = proc.StandardError;
  
  string line;
  
  while ((line = reader.ReadLine()) != null && !_cancel)
  
  {
  
    //Doing something with process line
  
  }
  
  proc.Close();

  This works fine, But when I run it in a few user machines, it just stops working with no error.

  I tried removing lines which hides shell window and turned it to this :

  Process proc = new Process();
  
  proc.StartInfo.FileName = "ffmpeg";
  
  proc.StartInfo.Arguments = string.Format("-ss {0} -i \"{1}\" -t {2}{3} DB\\Media\\{4}{5} -y",
  
       TimeSpan.Parse(row.Cells["StartdgvList"].Value.ToString()),
  
       openFileDialog.FileName, _durationTime, quality, newTmpSound,
  
       GetExtension(openFileDialog.FileName));
  
  if (!proc.Start()) return;
  
  proc.Close();

  and it start working in all the machines.

  I’m wondering if there’s some sort of service or components missing in some machines which makes the process fails when console is hiding.

  I appreciate if anyone has any idea.

  P.S : I installed Visual Studio 2012 on a machine which has problem hiding shell window and it suddenly start working. Maybe VS2012 installed somwthing on the machine which solved the problem.

• Java Process Builder runs ffmpeg commands very slowly

  16 septembre 2022, par Mary

  I'm trying to run ffmpeg in Java using ProcessBuilder. I'm on Windows. It works fine. But not sure why it's much slower than when I just run the same command in command prompt or PowerShell.

  


  Why is it ? Is there any ways to increase the speed ?

  


  processBuilder.command("C:\\Windows\\System32\\cmd.exe", "/c","ffmpeg.exe", "-y", "-i", video,"-vf","scale=720:-1","out.mp4");
    processBuilder.redirectErrorStream(true);
    try {
                process = processBuilder.start();
                BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
                
                String line="";
                while ((line = reader.readLine()) != null) {
                        System.out.println(line);
        }
        } catch (Exception e) {
            System.err.println("Error in processBuilder. ");
        }