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• What is Video Lagrange factor and how to achieve Constant bit rate ?

  12 décembre 2011, par Tarun

  I want to perform transcoding using FFMPEG. My target is to acheive CBR i.e Constant bit rate. But even using option like -maxrate and -minrate I am unable to acheive it.
  I know when converting to x264 if I choose CBR, it will deteriorate the video quality but I am OK with it since I want to use it for streaming.

  Please help me asap

• Separate mxf_essence_container_uls for audio and video.

  10 décembre 2011, par Carl Eugen Hoyos

  Separate mxf_essence_container_uls for audio and video.

• Why does ffmpeg never finish when converting a video from my web app ?

  30 septembre 2011, par Mike

  I am trying to convert a video when the user submits a form. It seems to convert ok but the file "is being used by another proccess" when I try to do anything with it. It looks like ffmpeg.exe never exits. My code is below is there anything I should be doing different to allow the process to release the file ? If I run this manually it exits fine.

  internal class ConversionUtility : Utility
  
  {
  
      public void Convert(string videoFileName)
  
      {
  
          var video = new VideoFile(videoFileName);
  
  
  
          if (!video.infoGathered)
  
              GetVideoInfo(video);
  
  
  
          var Params = string.Format("-y -i \"{0}\" -coder ac -me_method full -me_range 16 -subq 5 -sc_threshold 40 -vcodec libx264 -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -i_qfactor 0.71 -keyint_min 25 -b_strategy 1 -g 250 -r 20 \"{1}\"", video.Path, Path.ChangeExtension(videoFileName,".mp4"));
  
          //var Params = string.Format("-y -i \"{0}\" -acodec libfaac -ar 44100 -ab 96k -coder ac -me_method full -me_range 16 -subq 5 -sc_threshold 40 -vcodec libx264 -s 1280x544 -b 1600k -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -i_qfactor 0.71 -keyint_min 25 -b_strategy 1 -g 250 -r 20 c:\\output3.mp4", video.Path, videoFileName);
  
          //var Params = String.Format(" {0} \"{1}\"",this.FFmpegLocation, video.Path);
  
  
  
          var threadStart = new ParameterizedThreadStart(del => RunProcess(Params));
  
          var thread = new Thread(threadStart);
  
          thread.Start();            
  
          //RunProcess(Params);
  
      }
  
  }
  
  
  
  internal class Utility
  
  {
  
      public string FFmpegLocation { get; set; }        
  
      private string WorkingPath { get { return Path.GetDirectoryName(FFmpegLocation); } }
  
  
  
      protected string RunProcess(string Parameters)
  
      {
  
          //create a process info
  
          var oInfo = new ProcessStartInfo(this.FFmpegLocation, Parameters)
  
          {
  
              UseShellExecute = false,
  
              CreateNoWindow = true,
  
              RedirectStandardOutput = true,
  
              RedirectStandardError = true
  
          };
  
  
  
          //Create the output and streamreader to get the output
  
          string output = null; StreamReader srOutput = null;
  
  
  
          //try the process
  
          try
  
          {
  
              //run the process
  
              Process proc = System.Diagnostics.Process.Start(oInfo);
  
  
  
              proc.WaitForExit();
  
              //if (!proc.WaitForExit(10000))
  
              //    proc.Kill();
  
  
  
  
  
              //get the output
  
              srOutput = proc.StandardError;
  
  
  
              //now put it in a string
  
              output = srOutput.ReadToEnd();
  
  
  
              proc.Close();
  
          }
  
          catch (Exception)
  
          {
  
              output = string.Empty;
  
          }
  
          finally
  
          {
  
              //now, if we succeded, close out the streamreader
  
              if (srOutput != null)
  
              {
  
                  srOutput.Close();
  
                  srOutput.Dispose();
  
              }
  
          }
  
          return output;
  
      }