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• Revision 3304d4e6ca : Optimize the code to set the refernce frame right after reading the header. Cha

  10 octobre 2014, par hkuang

  Changed Paths :
   Modify /vp9/decoder/vp9_decodeframe.c

  
   Modify /vp9/decoder/vp9_decodemv.c

  
  
  Optimize the code to set the refernce frame right after reading the header.

  Change-Id : I495cf4a366e06e3220ed132500b1ba1c8448f708

• Revision 67e41fe2f6 : vp9 com/dec : avoid reading unavailable above/left in most cases at least the le

  16 octobre 2013, par James Zern

  Changed Paths :
   Modify /vp9/common/vp9_pred_common.c

  
   Modify /vp9/common/vp9_pred_common.h

  
   Modify /vp9/decoder/vp9_decodemv.c

  
  
  vp9 com/dec : avoid reading unavailable above/left

  in most cases at least the left column was a harmless race as it was
  left unused later in the code.

  Change-Id : I43211df66fb157c6feecf08c681add4fcf18b644

• Reading from a stream while its constantly being written to

  11 octobre 2017, par TomCrow

  I have a ip camera, which I need to read video stream from and get frames to bitmaps. For that I want to use NReco VideoConverter, which is ffmpeg .net wrapper. I use it like this :

  liveTask = ffMpeg.ConvertLiveMedia(inputStream, Format.h264, outputStream, Format.raw_video, new ConvertSettings() { CustomOutputArgs = "-pix_fmt rgb32" });
  
  liveTask.OutputDataReceived += new EventHandler(Recieved);
  
  liveTask.Start();

  Works fine, but my problem is that I need to read frames from that outputStream. The video converter writes to the stream constantly and calls my "Recieved" after every write. What I have is something like this :

  private void Recieved(object sender, EventArgs r)
  
  {
  
      int lenght = Width * Height * 4;
  
      if (outputStream.Length > lenght)
  
      {
  
          outputStream.Seek(0, SeekOrigin.Begin);
  
          byte[] buffer = new byte[lenght];
  
          int ret = outputStream.Read(buffer, 0, buffer.Length);
  
          Bitmap frame = CreateBitmapFromRawDataBuffer(buffer);
  
      }
  
  }

  Works great, but only for the first frame, cause the Seek is a problem, because I think position of the stream is always at the and and I also dont know how to check if there is written another frame, cause the lenght of the whole stream is only adding up. And that would be another problem, cause the streams lenght cant go up forever. The app is supposed to run nonstop 24/7, while decoding h264 data from a ip camera. Could anyone help me with this ? And if Iam using the stream the right way ? Thank you.

  Edit : For reading and writing together I know I could make custom stream with locking and separated positions for reading and writing, but what bothers me is the still adding lenght of the innerstream or outputstream in general and checking if there is next Width * Height * 4 bytes available for reading.