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• ffmpeg azure function consumption plan low CPU availability for high volume requests

  27 novembre 2017, par The Lemon

  I am running an azure queue function on a consumption plan ; my function starts an FFMpeg process and accordingly is very CPU intensive. When I run the function with less than 100 items in the queue at once it works perfectly, azure scales up and gives me plenty of servers and all of the tasks complete very quickly. My problem is once I start doing more than 300 or 400 items at once, it starts fine but after a while the CPU slowly goes from 80% utilisation to only around 10% utilisation - my functions cant finish in time with only 10% CPU. This can be seen in the image shown below.
  Does anyone know why the CPU useage is going lower the more instances my function creates ? Thanks in advance Cuan

  edit : the function is set to only run one at a time per instance, but the problem exists when set to 2 or 3 concurrent processes per instance in the host.json

  edit : the CPU drops get noticeable at 15-20 servers, and start causing failures at around 60. After that the CPU bottoms out at an average of 8-10% with individuals reaching 0-3%, and the server count seems to increase without limit (which would be more helpful if I got some CPU with the servers)

  Thanks again, Cuan.

  I’ve also added the function code to the bottom of this post in case it helps.

  

  

  using System.Net;
  
  using System;
  
  using System.Diagnostics;
  
  using System.ComponentModel;
  
  
  
  public static void Run(string myQueueItem, TraceWriter log)
  
  {
  
      log.Info($"C# Queue trigger function processed a request: {myQueueItem}");
  
      //Basic Parameters
  
          string ffmpegFile = @"D:\home\site\wwwroot\CommonResources\ffmpeg.exe";
  
          string outputpath = @"D:\home\site\wwwroot\queue-ffmpeg-test\output\";
  
          string reloutputpath = "output/";
  
          string relinputpath = "input/";
  
          string outputfile = "video2.mp4";
  
          string dir =  @"D:\home\site\wwwroot\queue-ffmpeg-test\";
  
  
  
      //Special Parameters
  
  
  
          string videoFile = "1 minute basic.mp4";
  
          string sub = "1 minute sub.ass";
  
      //guid tmp files
  
  
  
          // Guid g1=Guid.NewGuid();
  
          // Guid g2=Guid.NewGuid();
  
          // string f1 = g1 + ".mp4";
  
          // string f2 = g2 + ".ass";
  
          string f1 = videoFile;
  
          string f2 = sub;
  
      //guid output - we will now do this at the caller level
  
          string g3 = myQueueItem;
  
          string outputGuid = g3+".mp4";
  
      //get input files
  
      //argument
  
          string tmp = subArg(f1, f2, outputGuid );
  
      //String.Format("-i \"" + @"input/tmp.mp4" + "\" -vf \"ass = '" + sub + "'\" \"" + reloutputpath +outputfile + "\" -y");
  
      log.Info("ffmpeg argument is: "+tmp);
  
  
  
  
  
      //startprocess parameters
  
      Process process = new Process();
  
      process.StartInfo.FileName = ffmpegFile;
  
      process.StartInfo.Arguments =  tmp;
  
      process.StartInfo.UseShellExecute = false;
  
      process.StartInfo.RedirectStandardOutput = true;
  
      process.StartInfo.RedirectStandardError = true;
  
      process.StartInfo.WorkingDirectory = dir;
  
      //output handler
  
  
  
      process.OutputDataReceived += new DataReceivedEventHandler(
  
          (s, e) => 
  
          { 
  
              log.Info("O: "+e.Data);
  
          }
  
      );
  
      process.ErrorDataReceived += new DataReceivedEventHandler(
  
          (s, e) => 
  
          { 
  
              log.Info("E: "+e.Data);
  
          }
  
      );
  
      //start process
  
      process.Start();
  
      log.Info("process started");
  
      process.BeginOutputReadLine();
  
      process.BeginErrorReadLine();
  
      process.WaitForExit();
  
  }
  
  public static void getFile(string link, string fileName, string dir, string relInputPath){
  
      using (var client = new WebClient()){
  
          client.DownloadFile(link, dir + relInputPath+ fileName);
  
          }
  
  
  
  }
  
  public static string subArg(string input1, string input2, string output1){
  
      return String.Format("-i \"" + @"input/" +input1+ "\" -vf \"ass = '" + @"input/"+input2 + "'\" \"" + @"output/" +output1 + "\" -y");
  
  
  
  }

• Is it possible to be more accurate than a second for the snipping function below ? (MATLAB, ffmpeg)

  19 juillet 2021, par Micah T

  snip = 'ffmpeg -i %s -ss %d:%d:%d -t %d:%d:%d -async 1 -strict -2 %s';
snipstr = sprintf(snip,UncutFile,StartHRS,StartMIN,StartSEC,DurHRS,DurMIN,DurSEC,CutFile);
runsnip = system(snipstr);


  


  These lines snip a video based on starting time inputs and duration inputs. I need my videos to be snipped to times more accurate than a second.

  


  Thank you.

  


• How to use callback function in ffmpeg

  9 septembre 2014, par chesschi

  static int interrupt_cb(void *ctx) 

  I understand that many of the functions provided by the ffmpeg libraries are blocking. In order to control the blocking function to timeout, we can assign a callback function to interrupt_callback.

  For example, the avformat_open_input may take 1 second to complete. If I set a timer for 500 milliseconds, will it never be able to connect to the RTSP server and return non-zero value ?

  What is the optimal value for setting this timeout ? What will these blocking functions behave when the timeout value is too small ?

  What is the best approach to use this callback function ?