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• Pass ID3D11Texture2D back buffer to libx264 encoder

  17 janvier 2019, par Chris Sixsmith

  I’m writing a C++ program to encode frames from a DirectX game to the H.264/MPEG-4 AVC format. I am using libx264 alone with no other dependencies at the moment.

  I have a ID3D11Texture2D* resolved back buffer of the next game frame. I need to somehow copy this into the x264_picture input (apparently YUV420P format according to limited help I’ve found) but I cannot find any way to do so online.

  Here is my code at the moment :

  void Fx264VideoEncoder::Fx264VideoEncoderImpl::InitFrameInputBuffer(const FTexture2DRHIRef& BackBuffer, FFrame& Frame)
  
  {
  
      x264_picture_alloc(Frame.InputPicture, X264_CSP_I420, x264Parameters.i_width, x264Parameters.i_height);
  
  
  
      // We need to take the back buffer and convert it to an input format that libx264 can understand
  
      {
  
          ID3D11Texture2D* ResolvedBackBufferDX11 = (ID3D11Texture2D*)(GetD3D11TextureFromRHITexture(Frame.ResolvedBackBuffer)->GetResource());
  
          EPixelFormat PixelFormat = Frame.ResolvedBackBuffer->GetFormat();
  
  
  
          // ...?
  
      }
  
  }

• ffmpeg stream saving in python3

  25 novembre 2016, par b9703

  im trying to write a python script (for Windows OS) that can call on ffmpeg to recieve and save a live stream for later viewing. The initial call (subprocess.Popen(ARGS)) works as intended (start the stream saving) however i cant figure out how to programmatically end the process in a way that allows ffmpeg to finish its work. manually i can just press ’q’ or ’Ctrl-C’ and ffmpeg will produce a playable file.

  command = ['ffmpeg', '-i',
  
          url,
  
          '-acodec', 'copy',
  
          '-vcodec', 'copy',
  
          destination]
  
  
  
  recording = Popen(command)

  i have tried using recording.terminate() which didn’t work. I’ve also tried (although i’m pretty sure i did it wrong) using recording.communicate(b’q’) to send a message to the process. All solutions i’ve found online have failed in the same way (file is unreadable). I really dont know much about the subprocces module or about the intricacies of processes so i may be missing something obvious. I just want to end the ffmpeg process in a non-abrupt manner.

• Extract motion vectors from x265 (HEVC) encoded video with ffmpeg/libavcodec ?

  3 juillet, par John Allard

  I know that one can extract the motion vectors from an h264 encoded via by first setting the flag

  



  av_dict_set(&opts, "flags2", "+export_mvs", 0);


  



  then you can query the side-data for the motion vectors by doing this

  



  sd = av_frame_get_side_data(frame, AV_FRAME_DATA_MOTION_VECTORS);


  



  When I looked online to see if you can do something similar with HEVC encoded videos, I wasn't able to find any information. All I found was this by the definition of "AV_FRAME_DATA_MOTION_VECTORS"

  



  


  Motion vectors exported by some codecs (on demand through the
 export_mvs flag set in the libavcodec AVCodecContext flags2 option).

  
 


  The data is the AVMotionVector struct defined in
 libavutil/motion_vector.h.

  


  



  but there was no information on exactly which codecs export this motion vector information. How would I go about finding this out ?