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• Video encoded by ffmpeg.exe giving me a garbage video in c# .net

  10 septembre 2018, par Amit Yadav

  I want to record video through webcam and file to be saved in .mp4 format. So for recording i am using AforgeNet.dll for recording and for mp4 format i am encoding raw video into mp4 using ffmpeg.exe using NamedPipeStreamServer as i receive frame i push into the named pipe buffer. this process works fine i have checked in ProcessTheErrorData event but when i stop recording the output file play garbage video shown in the image below

  

  Here is Code for this

     Process Process;
  
    NamedPipeServerStream _ffmpegIn;
  
      byte[]  _videoBuffer ;
  
      const string PipePrefix = @"\\.\pipe\";
  
      public void ffmpegWriter()
  
      {
  
          if(File.Exists("outputencoded.mp4"))
  
          {
  
              File.Delete("outputencoded.mp4");
  
          }
  
  
  
          _videoBuffer = new byte[widht * heigth * 4];
  
          var audioPipeName = GetPipeName();
  
          var videoPipeName = GetPipeName();
  
          var videoInArgs = $@" -thread_queue_size 512 -use_wallclock_as_timestamps 1 -f rawvideo -pix_fmt rgb32 -video_size 640x480 -i \\.\pipe\{videoPipeName}";
  
          var videoOutArgs = $"-vcodec libx264 -crf 15 -pix_fmt yuv420p -preset ultrafast -r 10";
  
          _ffmpegIn = new NamedPipeServerStream(videoPipeName, PipeDirection.Out, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous, 0, _videoBuffer.Length);
  
          Process=StartFFmpeg($"{videoInArgs} {videoOutArgs} \"{"outputencoded.mp4"}\"", "outputencoded.mp4");
  
      }
  
  
  
   bool WaitForConnection(NamedPipeServerStream ServerStream, int Timeout)
  
      {
  
          var asyncResult = ServerStream.BeginWaitForConnection(Ar => { }, null);
  
  
  
          if (asyncResult.AsyncWaitHandle.WaitOne(Timeout))
  
          {
  
              ServerStream.EndWaitForConnection(asyncResult);
  
  
  
              return ServerStream.IsConnected;
  
          }
  
  
  
          return false;
  
      }
  
    static string GetPipeName() => $"record-{Guid.NewGuid()}";
  
  
  
   public static Process StartFFmpeg(string Arguments, string OutputFileName)
  
          {
  
              var process = new Process
  
              {
  
                  StartInfo =
  
                  {
  
                      FileName = "ffmpeg.exe",
  
                      Arguments = Arguments,
  
                      UseShellExecute = false,
  
                      CreateNoWindow = true,
  
                      RedirectStandardError = true,
  
                      RedirectStandardInput = true,
  
  
  
                  },
  
                  EnableRaisingEvents = true
  
              };
  
  
  
              //  var logItem = ServiceProvider.Get<ffmpeglog>().CreateNew(Path.GetFileName(OutputFileName));
  
  
  
              process.ErrorDataReceived += (s, e) => ProcessTheErrorData(s,e);
  
  
  
              process.Start();
  
  
  
              process.BeginErrorReadLine();
  
  
  
              return process;
  
          }
  
  </ffmpeglog>

  and Writing each frame like this.

   private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
  
          {
  
  
  
              try
  
              {
  
                  if (_recording)
  
                  {
  
  
  
                      using (var bitmap = (Bitmap) eventArgs.Frame.Clone())
  
                      {
  
                         var _videoBuffers = ImageToByte(bitmap);
  
  
  
  
  
                              if (_firstFrameTime != null)
  
                              {
  
                              bitmap.Save("image/" + DateTime.Now.ToString("ddMMyyyyHHmmssfftt")+".bmp");
  
  
  
                                  _lastFrameTask?.Wait();
  
  
  
  
  
                                  _lastFrameTask = _ffmpegIn.WriteAsync(_videoBuffers, 0, _videoBuffers.Length);
  
                              }
  
                              else
  
                              {
  
                                  if (_firstFrame)
  
                                  {
  
                                      if (!WaitForConnection(_ffmpegIn, 5000))
  
                                      {
  
                                          throw new Exception("Cannot connect Video pipe to FFmpeg");
  
                                      }
  
  
  
                                      _firstFrame = false;
  
                                  }
  
  
  
                                  _firstFrameTime = DateTime.Now;
  
                                  _lastFrameTask?.Wait();
  
  
  
                                  _lastFrameTask = _ffmpegIn.WriteAsync(_videoBuffers, 0, _videoBuffers.Length);
  
  
  
                              }
  
  
  
                      }
  
                  }
  
                  using (var bitmap = (Bitmap) eventArgs.Frame.Clone())
  
                  {
  
                      var bi = bitmap.ToBitmapImage();
  
                      bi.Freeze();
  
                      Dispatcher.CurrentDispatcher.Invoke(() => Image = bi);
  
                  }
  
              }
  
              catch (Exception exc)
  
              {
  
                  MessageBox.Show("Error on _videoSource_NewFrame:\n" + exc.Message, "Error", MessageBoxButton.OK,
  
                      MessageBoxImage.Error);
  
                  StopCamera();
  
              }
  
          }

  Even i have written each frame to disk as bitmap .bmp and frames are correct but i don’t know what’s i am missing here ? please help thanks in advance.

• How do I set ffmpeg pipe output ?

  5 décembre 2019, par mr_blond

  I need to read ffmpeg output as pipe.
  There is a code example :

      public static void PipeTest()
  
      {
  
          Process proc = new Process();
  
          proc.StartInfo.FileName = Path.Combine(WorkingFolder, "ffmpeg");
  
          proc.StartInfo.Arguments = String.Format("$ ffmpeg -i input.mp3 pipe:1");
  
          proc.StartInfo.UseShellExecute = false;
  
          proc.StartInfo.RedirectStandardInput = true;
  
          proc.StartInfo.RedirectStandardOutput = true;
  
          proc.Start();
  
  
  
          FileStream baseStream = proc.StandardOutput.BaseStream as FileStream;
  
          byte[] audioData;
  
          int lastRead = 0;
  
  
  
          using (MemoryStream ms = new MemoryStream())
  
          {
  
              byte[] buffer = new byte[5000];
  
              do
  
              {
  
                  lastRead = baseStream.Read(buffer, 0, buffer.Length);
  
                  ms.Write(buffer, 0, lastRead);
  
              } while (lastRead > 0);
  
  
  
              audioData = ms.ToArray();
  
          }
  
  
  
          using(FileStream s = new FileStream(Path.Combine(WorkingFolder, "pipe_output_01.mp3"), FileMode.Create))
  
          {
  
              s.Write(audioData, 0, audioData.Length);
  
          }
  
      }

  It’s log from ffmpeg, the first file is readed :

  Input #0, mp3, from ’norm.mp3’ :
  Metadata :
  encoder : Lavf58.17.103
  Duration : 00:01:36.22, start : 0.023021, bitrate : 128 kb/s
  Stream #0:0 : Audio : mp3, 48000 Hz, stereo, fltp, 128 kb/s
  Metadata :
  encoder : Lavc58.27

  Then pipe :

  [NULL @ 0x7fd58a001e00] Unable to find a suitable output format for ’$’
  $ : Invalid argument

  If I run "-i input.mp3 pipe:1", the log is :

  Unable to find a suitable output format for ’pipe:1’ pipe:1 : Invalid
  argument

  How do I set correct output ? And how should ffmpeg know what the output format is at all ?

• How to make a MPEG-DASH MPD which starts the playback in the middle of the first segment ?

  18 septembre 2018, par ravin.wang

  Here are the reproduce steps :

  1. Normalize an H.264 video stream

     ffmpeg -i 2.h264 -c:v libx264 -intra -r 25 -vf scale=640x360,setdar=16:9 2@25fps@intra@640x360.h264

     (*) After that, I got an H.264 stream where all pictures are H.264 IDR frames, and fps is 25, resolution is 640x360, aspect-ratio is 16:9.

  2. Generate an MP4 file

     MP4Box -add 2@25fps@intra@640x360.h264:timescale=1000 -fps 25 2@25fps@intra@640x360.mp4

  3. Make dash MP4 fragmented content, including init mp4, .m4s files and one .mpd file

     MP4Box -dash 5000 -frag 5000 -dash-scale 1000 -frag-rap -segment-name ’seg_second$Number$’ -segment-timeline -profile live 2@25fps@intra@640x360.mp4

  4. Copy and publish all these files to a folder under one HTTPD server

  5. I want to play from 4s of the first segment, and don’t display any frames before 4s, so I changed the .MPD file to modify the fields "SegmentTemplate@presentationTimeOffset", "SegmentTimeline:S@d/t", like as :
     

     <?xml version="1.0"?>
<mpd xmlns="urn:mpeg:dash:schema:mpd:2011" minbuffertime="PT1.500S" type="static" mediapresentationduration="PT0H0M26.000S" maxsegmentduration="PT0H0M5.000S" profiles="urn:mpeg:dash:profile:isoff-live:2011">
<period duration="PT0H0M26.000S">
<adaptationset segmentalignment="true" maxwidth="640" maxheight="360" maxframerate="25" par="16:9" lang="und">
 <segmenttemplate presentationtimeoffset="4000" media="seg_second$Number$.m4s" timescale="1000" startnumber="1" initialization="seg_secondinit.mp4">
   <segmenttimeline>
       <s d="1000" t="4000"></s>
       <s d="5000" r="4"></s>
   </segmenttimeline>
  </segmenttemplate>
<representation mimetype="video/mp4" codecs="avc3.64101E" width="640" height="360" framerate="25" sar="1:1" startwithsap="1" bandwidth="2261831">
</representation>
</adaptationset>
</period>
</mpd>

     
     

  6. Play the MPD url from VLC player, or Edge browser, it always starts the the first frame of the first segment, the frames between 0s 4s are also displayed unexpectedly.

  What’s wrong with my steps ? Or any other options for it ?