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• Stream frame from video to pipeline and publish it to HTTP mjpeg via ffmpeg

  18 juillet 2018, par Rafał Sardaw

  Let’s say I have very simple program which has been written in C++ with usage of OpenCV 3.4 under Windows 10.

  VideoCapture cap("test.avi");
  
  Mat frame; 
  
  while(true){
  
      if (!cap.read(frame))  
  
      { 
  
          break;
  
      }
  
      // SEND FRAME TO PIPE
  
  }

  It’s just simple example of reading frame by frame avi video, but in the end it’s going to be server-side application which produces modified stream from few ip cameras. I want to use html5 video tag to display output directly on website, but it’s quite hard to find useful information related with that topic ( for Windows ). If I understand it correctly I need to define pipeline and send there MJPEG stream, with help of FFMPEG, where FFMPEG will create local HTTP server on specific port. Anyone ever challenged similar task under Windows ? I guess that 80% of task is related with proper usage of ffmpeg command line tool, one of my priorities is minimal modification of application.

  So to make long story short, I have application which I can call directly from command line :

  stream_producer.exe CAMERA_1 

  and I want to be able to see MJPEG stream under :

  http://localhost:1234

  which can be displayed on local website in intranet.

  Regards.

• avfilter/vf_geq : use per-thread AVExpr for expression evaluation

  28 décembre 2019, par Marton Balint

  avfilter/vf_geq : use per-thread AVExpr for expression evaluation
  There was no consensus about separating AVExprState from AVExpr so here is a
  
  minimal patch using the existing AVExpr to fix ticket #7528.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_geq.c

• Hardware Accelerated H264 Decode using DirectX11 in Unity Plugin for UWP

  8 janvier 2019, par rohit n

  I’ve built an Unity plugin for my UWP app which converts raw h264 packets to RGB data and renders it to a texture. I’ve used FFMPEG to do this and it works fine.

  int framefinished = avcodec_send_packet(m_pCodecCtx, &packet);
  
  framefinished = avcodec_receive_frame(m_pCodecCtx, m_pFrame);
  
  // YUV to RGB conversion and render to texture after this

  Now, I’m trying to shift to hardware based decoding using DirectX11 DXVA2.0.

  Using this : https://docs.microsoft.com/en-us/windows/desktop/medfound/supporting-direct3d-11-video-decoding-in-media-foundation

  I was able to create a decoder(ID3D11VideoDecoder) but I don’t know how to supply it the raw H264 packets and get the YUV or NV12 data as output.
  (Or if its possible to render the output directly to the texture since I can get the ID3D11Texture2D pointer)

  so my question is, How do you send the raw h264 packets to this decoder and get the output from it ?

  Also, this is for real time operation so I’m trying to achieve minimal latency.

  Thanks in advance !