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• Streaming jpegs to a video on my server

  2 décembre 2013, par Andrew Simpson

  I found a solution to my problem IF I was using a Linux/UNIX machine. It is FFServer from the tools from FFMPEG.

  I had been using FFMPEG on my client Winform Desktop C# to convert jpegs into an OGG video file for playback.

  I have now been tasked with uploading the jpegs to my server and rendering it as a video.

  Optimum, I would start an FFMPEG process on my client PC and supply its stdin with jpegs in byte array format. I have achieved this (I have looked around) but is there a way to redirect the stdoutput to my server that can be picked up by my code on the server and render in real-time to my web User ?

  I have looked on the ffmpeg web site but I am unsure how to 'fit' it in with my process.

  This is my code so far :

      public byte[] EncodeAndUploadImages(string _args1, string _fn)  
  
      {
  
          byte[] _data = null;
  
          try
  
          {
  
              clientBuild = new Process();
  
              clientBuild.StartInfo.WorkingDirectory = Environment.CurrentDirectory;
  
              clientBuild.StartInfo.Arguments = " -f mjpeg -r 30 -i - -c:v libtheora -q:v 7 -r 30 -f ogg -";
  
              clientBuild.StartInfo.FileName = Environment.CurrentDirectory + @"\ffmpeg.exe";
  
              clientBuild.StartInfo.UseShellExecute = false;
  
              clientBuild.StartInfo.RedirectStandardOutput = true;
  
              clientBuild.StartInfo.RedirectStandardError = true;
  
              clientBuild.StartInfo.RedirectStandardInput = true;
  
              clientBuild.StartInfo.CreateNoWindow = true;
  
              clientBuild.StartInfo.LoadUserProfile = false;
  
              clientBuild.EnableRaisingEvents = true;    
  
              clientBuild.Start();
  
  
  
              using (BinaryWriter bw = new BinaryWriter(clientBuild.StandardInput.BaseStream))
  
              {
  
                 //I am simulating a stream of jpegs coming in////////////////
  
                  for (int i = 1; i < 20; i++)
  
                  {
  
                      using (MemoryStream ms = new MemoryStream())
  
                      {
  
                          System.Diagnostics.Debug.Write(i.ToString("00000"));
  
                          Bitmap bmp = new Bitmap("h:\\streamin\\" + i.ToString("00000") + ".jpg");
  
                          bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
  
                          bw.Write(ms.ToArray());                           
  
                          bmp.Dispose();
  
                          ms.Close();
  
                      }
  
                  }
  
                  bw.Close();
  
              }
  
  
  
              // I need some in my ffmpeg arguments to do something here//////   
  
              mStandardOutput = clientBuild.StandardOutput.BaseStream;
  
              mStandardOutput.BeginRead(mReadBuffer, 0, mReadBuffer.Length, StandardOutputReadCallback, null);
  
              clientBuild.WaitForExit();
  
              _data = mStandardOutputMs.ToArray();
  
              mStandardOutput.Close();
  
          }
  
          catch (Exception _ex)
  
          {
  
  
  
          }
  
          finally
  
          {
  
              clientBuild.Dispose();
  
          }
  
          return _data;
  
      }

  Thanks

• ffmpeg udp/tcp stream receive frame not same as sent

  21 novembre 2013, par vivienlwt

  I am streaming a video on raspberrypi using command :

  ffmpeg -re -threads 2 -i sample_video.m2v -f mpegts - | \
  
  ffmpeg -f mpegts -i - -c copy -f mpegts udp://192.168.1.100:12345

  The remote PC with 192.168.1.100 uses ffmpeg library to listen to the input stream. For example :

  informat = ffmpeg::av_find_input_format("mpegts");
  
  avformat_open_input(&pFormatCtx, "udp://192.168.1.100:12345", informat, options);

  However, when I compute the hash value of each decoded frame on two sides (i.e. raspberrypi and PC), they DON'T MATCH at all. A weird thing is, among 2000 frames, there are in total 10 frames whose hash value are the same on the sender and receiver side. The match result look like this :

  00000....00011000...00011110000...000

  where 0 indicates non-match and 1 indicates match. The matched frame appeared 2 6 in sequence and appeared rarely while most of the other frames has different hash value.

  The hash is computed on the frame data buffer extracted using avpicture_layout(). On the Pi side, I just stream the video to a local port and there's a local process using the same code to decode and hash the frames :

  ffmpeg -re -threads 2 -i sample_video.m2v -f mpegts - | \
  
  ffmpeg -f mpegts -i - -c copy -f mpegts udp://localhost:12345
  
  ...

  The streaming source raspberry pi, is connected directly to the PC using cable. I don't think it is a packet loss problem. Because, first, I rerun the same process several times and the hash value of the received frames are the same (otherwise the result should be different because packet loss is probabilistic). Secondly, I even try to stream on tcp ://192.168.1.100:12345 (and "tcp ://192.168.1.100:12345 ?listen" on PC), and the received frame hash are still the same - different than the hash result on the Pi.

  So, does anyone know why the streaming to a remote address will yield different decoded frames ? Maybe I am missing some details.

  Thanks in advance !!

• ffmpeg stops generating mp4 1.5 seconds before end

  26 septembre 2016, par Alex Konetchy

  I’m no ffmpeg expert. I’m trying to generate a video with a matching image overlapped on top to create a cinemagraph effect. For the basic test I run this, but it stops creating frames about 1.5 seconds before the end of the output video is complete.

  ffmpeg -ss 10.0000 -t 15.00000 -i waterfall.mp4 -loop 1 -i output.png -an output1.mp4

  Could anyone point me in the right direction for why this might be occurring ? All help is appreciated !