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• Improve ffmpeg CPU usage by compromising quality

  29 septembre 2016, par Hardik Juneja

  I am using FFMpeg for screen capturing.
  I am looking for a screen capturing tool that will run on 1000 of VMs (windows and mac).The VMs have limited CPU (1 core) and 2GB ram and No GPU.

  Currently I invoke ffmpeg with

  ffmpeg  -y -framerate 8 -f dshow -f gdigrab -i "desktop"  -c:v libx264  -crf 0 -preset ultrafast -threads 0 temp.mkv

  I am using gdigrab to capture screen ? Is there any better options that might reduce cpu usage ? or changing the encoder or format ?

  I am aiming for 4-5% reduction in CPU usage.

  Thanks in advance

• Convert static file to h264 stream with FFmpeg [on hold]

  28 août 2013, par Vprnl

  I'm building a NodeJS application that converts a static videofile to a streamable video which is being sent to a client (iPad or browser) on the fly (using the fluent-ffmpeg module).

  Everything is set and all I need now is to configure ffmpeg correctly. But I'm having a lot of problems with ffmpeg.

  With my current settings, I hear audio right away, but the picture starts a couple of seconds later. Then, my 30 second test file has been compressed to 3 seconds of high speed imagery.

  How can I configure my ffmpeg so it will stream the mp4 correctly (in one pass through of course). It seems it is streaming raw h264, if that is the case how can I force the mp4 container. I thought I was doing that by using '-f mp4'

  my correct settings are :

     '-crf 22','-c:v libx264','-f mp4','-movflags','faststart+frag_keyframe'

  I've also tried :

   '-r 30','-crf 30','-analyzeduration 0','-probesize 1000','-rc_lookahead 0','-fflags nobuffer','-g 75','-ss 0','-threads 0','-vcodec libx264','-qcomp 0.6','-qmin 10','-qmax 51','-qdiff 4','-b:v 400k','-maxrate 400k','-bufsize 800k','-acodec mp3','-ab 192k','-ar 44100','-tune zerolatency','-f mp4','-movflags','faststart+frag_keyframe'

  As you can see by the amount of options I've tried, I'm getting pretty desperate. I'm basically just running around in the dark.

  I don't think it matters much but these are my request headers :

                      res.writeHead(200, { // NOTE: a partial http response
  
                          'Content-Type':'video/mp4',
  
                          'Content-Length':stat.size,
  
                          'Content-Range':'bytes '+start+'-'+end+'/'+stat.size,
  
                          'Transfer-Encoding':'chunked'
  
                      });

• How to get the video duration using FFMPEG in C# asp.net

  23 août 2013, par Hamad

  I want to get the video file duration in string using C#. I searched the internet and all i get is :

  ffmpeg -i inputfile.avi

  And every1 say that parse the output for duration.

  Here is my code which is

  string filargs = "-y -i " + inputavi + " -ar 22050 " + outputflv;
  
      Process proc;
  
      proc = new Process();
  
      proc.StartInfo.FileName = spath;
  
      proc.StartInfo.Arguments = filargs;
  
      proc.StartInfo.UseShellExecute = false;
  
      proc.StartInfo.CreateNoWindow = false;
  
      proc.StartInfo.RedirectStandardOutput = false;
  
      try
  
      {
  
          proc.Start();
  
  
  
      }
  
      catch (Exception ex)
  
      {
  
          Response.Write(ex.Message);
  
      }
  
  
  
      try
  
      {
  
          proc.WaitForExit(50 * 1000);
  
      }
  
      catch (Exception ex)
  
      { }
  
      finally
  
      {
  
          proc.Close();
  
      }

  Now please tell me how can i save the output string and parse it for the video duration.

  Thanks and regards,