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• How to encode grayscale video streams with FFmpeg ?

  26 octobre 2014, par Gearoid Murphy

  I’ve got a grayscale video stream coming off a Firewire astronomy camera, I’d like to use FFmpeg to compress the video stream but it will not accept single byte pixel formats for the MPEG1VIDEO codecs. How can I use the FFmpeg API to convert grayscale video frames into a frame format accepted by FFmpeg ?

• 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;
  
      }

• H.264 (MP4) video not play in IE9, but will play in Safari [closed]

  27 septembre 2011, par Austin S

  I have encoded a video using FFMPEG into three formats : WebM, MP4, and FLV. Chrome, Mozilla, and theoretically Opera (although I haven't tested it) should all use the WebM version. IE9, iOS devices, and Adriod should use the MP4 container. While all legacy browsers should default back to the flash version of the file. I'm using video-js to help serve the content. The content is set to preload and autoplay.

  I have found that everything is working as intended except for IE9, where all I get is the poster image and a white dot that typically spins indicating that the file is loading however it is not spinning in this scenario. The MP4 file opens in Safari, an iPad, an iPhone, and an Andriod - verifying that the file is infact legit.

  The following is the specs for the MP4 file when I stream it using VLC. I don't know if this is particularly useful, I'm just trying to provide as much detail as possible.

  VLC Codec Details

  • Stream 0

    Type : Video

    Codec : MPEG-4 Video (mp4v)

    Language : English

    Resolution : 480x270

    Frame rate : 2997

  • Stream 1

    Type : Audio

    Codec : MPEG AAC Audio (mp4a)

    Language : English

    Channels : Stereo

    Sample rate : 48000 Hz

  When accessing videojs.com from my coworkers computer, the video on their main page wouldn't play the video correctly in IE9, but we could hear the audio. When I went to another coworkers computer it played just fine. I'm wondering if IE9, or video-js, is tempermental depending on how updated your OS is.

  The fact that I'm working on XP with IE7 is making this all the more difficult to fix, so if you have any suggestions on what could point me in the right direction, I would greatly appreciate it !

  Thanks,

  Austin S