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• How to extract stream of images from video file using ffmpeg

  13 décembre 2013, par user3032143

  I want to extract stream of images from a video file using ffmpeg.

  I know I can extract them straight to the hard drive using these arguments :

  -i - -qscale 1 h :\out\img-%05d.jpg

  But i would like to extract directly to a stream.

  This is my code so far :

  private void ExtractImagesFromVideo(byte[] data,string _args)
  
      {
  
          try
  
          {
  
              serverBuild = new Process();
  
              serverBuild.StartInfo.WorkingDirectory = Environment.CurrentDirectory;
  
              serverBuild.StartInfo.Arguments = _args;
  
              serverBuild.StartInfo.FileName = Environment.CurrentDirectory + @"\ffmpeg.exe";
  
              serverBuild.StartInfo.UseShellExecute = false;
  
              serverBuild.StartInfo.RedirectStandardOutput = true;
  
              serverBuild.StartInfo.RedirectStandardError = true;
  
              serverBuild.StartInfo.RedirectStandardInput = true;
  
              serverBuild.StartInfo.CreateNoWindow = true;
  
              serverBuild.StartInfo.LoadUserProfile = false;
  
              serverBuild.EnableRaisingEvents = true;
  
              serverBuild.Start();
  
  
  
              using (BinaryWriter bw = new BinaryWriter(serverBuild.StandardInput.BaseStream))
  
              {
  
                  bw.Write(data);
  
              }
  
  
  
              mStandardOutput = serverBuild.StandardOutput.BaseStream;
  
              mStandardOutput.BeginRead(mReadBuffer, 0, mReadBuffer.Length, StandardOutputReadCallback, null);
  
              serverBuild.WaitForExit();
  
              byte[] _data = mStandardOutputMs.ToArray();
  
              mStandardOutput.Close();
  
  
  
          }
  
          catch (Exception _ex)
  
          {
  
  
  
          }
  
          finally
  
          {               
  
              serverBuild.Dispose();
  
          }
  
      }

  and I call like like this :

       string _argsOut = @"-i pipe:0 -qscale 1 -f mjpeg pipe:1 ";
  
       ExtractImagesFromVideo(data, _argsOut);

  and it hangs on this line :

  bw.Write(data);

  thanks

• nutenc/write_index : warn if 2 consecutive keyframes have the same PTS and discard...

  22 décembre 2013, par Michael Niedermayer

  nutenc/write_index : warn if 2 consecutive keyframes have the same PTS and discard the 2nd
  This fixes an assertion failure and regression and restores previous behaviour
  
  Fixes Ticket3197
  An alternative would be to fail hard in this case and refuse to mux such data.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/nutenc.c

• retransmit incoming vp8-rtp-udp stream as the same rtp

  9 janvier 2014, par rub

  S'cuse the title.. I find it hard even to write up the question :

  I am trying to use ffmpeg to channel an incoming realtime video stream (Android VoIP call) into a local-network PC. I have compiled FFMPEG to android using the most recent NDK/FFMPEG git sources, but I find it hard to get all the configuration right.

  Now, I understand that FFMPEG has retransmission functionality - I found a number of command line examples, similar to what I need :

  **ffmpeg -re -i udp://1.2.3.4:1234  http://127.0.0.1:8090/feed1.ffm**

  What I don't understand :

  1. Which process to use : ffmpeg / ffserver / ffplay ??
  2. Do I have to use a ffserver.conf file (IP security right ?)
  3. Can I use sdp for incoming udp channel (I have the SDP from the VoIP/SIP call)

  Thanks