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• ffmpeg - How to increase performance ?

  7 mai 2017, par Thanh Dao

  I’m trying to speed up and add background to mp4 videos. It taken a lots of time.

  ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=0.91*PTS[i]; [0:a]atempo=1.1000[p]" -map "[i]" -map "[p]" output-1.mp4 2>&1

  Above command take about 30 minutes to do. The size of input file about 30-40MB, is not too large.
  And next, I run below command to add background to video, take about 30 mins (Background’s resolution is 1280x720)

  ffmpeg -i output-1.mp4 -i background.png -filter_complex "overlay=0:0" output.mp4 2>&1

  It make my system very slow, and performance is very bad.
  What can I do to improve ?

• 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,

• 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'
  
                      });