Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

• 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().CreateNew(Path.GetFileName(OutputFileName));
  
              process.ErrorDataReceived += (s, e) => ProcessTheErrorData(s,e);
  
              process.Start();
  
              process.BeginErrorReadLine();
  
              return process;
          }
  

  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.

• FFmpeg blend mode is not working with `multiply` option

  10 septembre 2018, par Praveen Tamil

  When using multiply blend option, the green color image is generated

  Hi I'm using below code

  ffmpeg -i gradient_0.png -i gradient_1.png -filter_complex "[0:v]setsar=1[v0];[1:v]setsar=1[v1];[v1][v0]blend=all_mode=multiply" output.jpeg -y
  

  Input 1 with color code #eaeae9 Input 2 with color code #a9a499 Result with color code #3eda1e But I need output like below image with color code #9b968c

• FFMPEG, C++, Memory leak, what am I doing wrong ?

  10 septembre 2018, par MrSmith

  So I've built this app that consumes an IP cameras rtsp feed and does fun things with it, however I have a small memory leak that I have only just now pinned down.

  If I just run this

  while (av_read_frame(input_format_context, &input_packet) >= 0) {}
  

  It will just grow'n grow'n grow ... So what am I missing?

  Am using a windows port of ffmpeg and my version is 58.9.100.0 Could it be a leak in FFMPEG itself?

• How can I turn libavformat error messages off

  10 septembre 2018, par amrhassan

  By default, libavformat writes error messages to stderr, Like:

  Estimating duration from bitrate, this may be inaccurate

  How can I turn it off? or better yet, pipe it to my own neat logging function?

  Edit: Redirecting stderr to somewhere else is not acceptable since I need it for other logging purposes, I just want libavformat to not write to it.

• Is there any way to create a WEBM file like this ?

  10 septembre 2018, par yksnmel

  I'm trying to convert my mp4 to webm with these settings. Does anyone know how can I do this on FFMpeg?

  Here is the settings:

  Format                         : WebM
  Format version                 : Version 2
  File size                      : 296 MiB
  Duration                       : 3 min 31 s
  Overall bit rate               : 11.8 Mb/s
  Writing application            : Lavf56.40.101
  Writing library                : Lavf56.40.101
  Video
  ID                             : 1
  Format                         : VP8
  Codec ID                       : V_VP8
  Duration                       : 3 min 31 s
  Bit rate                       : 11.3 Mb/s
  Width                          : 1 216 pixels
  Height                         : 720 pixels
  Display aspect ratio           : 5:3
  Frame rate mode                : Constant
  Frame rate                     : 25.000 FPS
  Compression mode               : Lossy
  Bits/(Pixel*Frame)             : 0.516
  Stream size                    : 284 MiB (96%)
  Default                        : Yes
  Forced                         : No
  

  Thanks!