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• Revision 92479d9526 : Make update_partition_context faster Use vpx_memset for updating the partition

  26 juin 2013, par Jingning Han

  Changed Paths :
   Modify /vp9/common/vp9_blockd.h

  
  
  Make update_partition_context faster

  Use vpx_memset for updating the partition contexts. Thanks to Noah
  for pointing out the need of refactoring in this part.

  Change-Id : I67fb78429d632298f1cd8a0be346cc76f79392a6

• Revision a63e31e81e : fix test compile error since : 92479d9 Make update_partition_context faster fix

  29 juin 2013, par James Zern

  Changed Paths :
   Modify /vp9/common/vp9_blockd.h

  
  
  fix test compile error

  since :
  92479d9 Make update_partition_context faster

  fixes :
  vp9/common/vp9_blockd.h:408:22 : error :
  non-constant-expression cannot be narrowed from type 'int' to 'char' in
  initializer list [-Wc+×narrowing]
  char pcvalue[2] =  (0xe << boffset), (0xf <

• Faster encoding of realtime 3d graphics with opengl and x264

  26 décembre 2012, par cloudraven

  I am working on a system that sends a compressed video to a client from 3d graphics that are done in the server as soon as they are rendered.
  I already have the code working, but I feel it could be much faster (and it is already a bottleneck in the system)

  Here is what I am doing :

  First I grab the framebuffer

  glReadBuffer( GL_FRONT );
  
  glReadPixels( 0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, buffer ); 

  Then I flip the framebuffer, because there is a weird bug with swsScale (which I am using for colorspace conversion) that flips the image vertically when I convert. I am flipping in advance, nothing fancy.

  void VerticalFlip(int width, int height, byte* pixelData, int bitsPerPixel)
  
  {
  
  byte* temp = new byte[width*bitsPerPixel];
  
  height--; //remember height array ends at height-1
  
  
  
  
  
  for (int y = 0; y < (height+1)/2; y++) 
  
  {
  
      memcpy(temp,&pixelData[y*width*bitsPerPixel],width*bitsPerPixel);
  
      memcpy(&pixelData[y*width*bitsPerPixel],&pixelData[(height-y)*width*bitsPerPixel],width*bitsPerPixel);
  
      memcpy(&pixelData[(height-y)*width*bitsPerPixel],temp,width*bitsPerPixel);
  
  }
  
  delete[] temp;
  
  }

  Then I convert it to YUV420p

  convertCtx = sws_getContext(width, height, PIX_FMT_RGB24, width, height, PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  uint8_t *src[3]= {buffer, NULL, NULL}; 
  
  
  
  sws_scale(convertCtx, src, &srcstride, 0, height, pic_in.img.plane, pic_in.img.i_stride);

  Then I pretty much just call the x264 encoder. I am already using the zerolatency preset.

  int frame_size = x264_encoder_encode(_encoder, &nals, &i_nals, _inputPicture, &pic_out);

  My guess is that there should be a faster way to do this. Capturing the frame and converting it to YUV420p. It would be nice to convert it to YUV420p in the GPU and only after that copying it to system memory, and hopefully there is a way to do color conversion without the need to flip.

  If there is no better way, at least this question may help someone trying to do this, to do it the same way I did.