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• Play UDP live video stream in UWP

  19 avril 2018, par Nicolas Séveno

  I need to display a live video stream in a UWP application.

  The video stream comes from a GoPro. It is transported by UDP messages. I think it is a MPEG-2 TS stream.

  I can play it successfully using FFPlay with the following command line :

  ffplay -fflags nobuffer -f:v mpegts udp://:8554

  I would like to play it with MediaPlayerElement without using a third party library.

  According to the following page :
  https://docs.microsoft.com/en-us/windows/uwp/audio-video-camera/supported-codecs
  UWP should be able to play it. (I installed the "MPEG 2 video extension" in the Windows Store).

  I tried using DatagramSocket and the MessageReceived event to receive the UDP packets, it works without problem :

  _datagramSocket = new DatagramSocket();
  
  _datagramSocket.MessageReceived += (s, args) =>
  
  {
  
      Debug.WriteLine("message received");
  
  };
  
  await _datagramSocket.BindServiceNameAsync(8554);

  Then I create a MseStreamSource :

  _mseStreamSource = new MseStreamSource();
  
  _mseStreamSource.Opened += (_, __) =>
  
  {
  
      _mseSourceBuffer = _mseStreamSource.AddSourceBuffer("video/mp2t");
  
  };
  
  this.MediaSource = MediaSource.CreateFromMseStreamSource(_mseStreamSource);

  And in the DatagramSocket.MessageReceived event I send the messages to the MseStreamSource :

  using (IInputStream stream = args.GetDataStream())
  
  {
  
      _mseSourceBuffer.AppendStream(stream);
  
  }

  The AppendStream method fails with error HRESULT 0x8070000B for some packets.
  If I catch the error, the MediaPlayerElement displays the message "video not supported or incorrect file name". (not sure of the message, my Windows is in French).

  Is the MseStreamSource the correct way to display the stream ? Is there a better solution ?

• lavf : deprecate av_stream_get_end_pts()

  17 août 2022, par Anton Khirnov

  lavf : deprecate av_stream_get_end_pts()
  According to its documentation it returns "pts of the last muxed packet
  
  + its duration", but the value it actually returns right now is
  
  (possibly guessed) dts after muxer-internal bitstream filtering (if
  
  any).
  This function was added for ffmpeg.c, but it is not used there anymore.
  
  Since the value it returns is ill-defined and so inappropriate for any
  
  serious use, deprecate it.
  

  • [DH] doc/APIchanges
  • [DH] libavformat/avformat.h
  • [DH] libavformat/mux_utils.c
  • [DH] libavformat/version_major.h

• Read H264 streaming from Elp H264 with OpenCV + Pyhton

  15 janvier 2017, par Francesco Paissan

  I’m trying to read an udp streaming of a H264 encoded image. The software structure is like follows :

  On a BeagleBoneBlack (Ubuntu 16.04) I’ve an Elp H264 cam (see here : https://www.amazon.com/ELP-Support-Android-Windows-Surveillance/dp/B00VDSBH9G ). I stream frames with ffmpeg on a Unicast UDP Stream.

  I want to read this images from python and opencv to be able to process them.

  I tried with this simple code to see if the cap is opened or not :

  import cv2

  try:
  
       cap = cv2.VideoCapture("udp://localhost:1234/")
  
      cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));
  
  except Exception, e:
  
      print str(e)

  But when I run this script python says :

  DtsGetHWFeatures : Create File Failed DtsGetHWFeatures : Create File
  Failed Running DIL (3.22.0) Version DtsDeviceOpen : Opening HW in mode
  0 DtsDeviceOpen : Create File Failed libva info : VA-API version 0.38.1
  libva info : va_getDriverName() returns -1 libva error :
  va_getDriverName() failed with unknown libva error,driver_name=(null)
  libva info : VA-API version 0.38.1 libva info : va_getDriverName()
  returns -1 libva error : va_getDriverName() failed with unknown libva
  error,driver_name=(null) libva info : VA-API version 0.38.1 libva info :
  va_getDriverName() returns -1 libva error : va_getDriverName() failed
  with unknown libva error,driver_name=(null) libva info : VA-API version
  0.38.1 libva info : va_getDriverName() returns -1 libva error : va_getDriverName() failed with unknown libva error,driver_name=(null)
  GStreamer Plugin : Embedded video playback halted ; module vaapidecode
  reported : Could not initialize supporting library. OpenCV
  Error : Unspecified error (GStreamer : unable to start pipeline ) in
  cvCaptureFromCAM_GStreamer, file /builddir/build/BUILD/opencv-
  2.4.12.3/modules/highgui/src/cap_gstreamer.cpp, line 816 /builddir/build/BUILD/opencv-2.4.12.3/modules/highgui/src/cap_gstreamer.cpp:816 :
  error : (-2) GStreamer : unable to start pipeline in function
  cvCaptureFromCAM_GStreamer

  Can anybody help me ?

  Thanks,

  Francesco.