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• Stream video over serial port using FFmpeg [closed]

  13 septembre 2020, par Rasoul Sharifian

  I am using the FFmpeg library to stream videos by UDP and LAN cables, something like this :

  


  What we have now

  


  But as our embedding systems just have serial ports the data must stream over the serial ports.
something like this :

  


  What we are trying to achieve

  


  So the question is : Is it possible to stream videos over the serial port using the FFmpeg library ? Or is there any other library that can compress and stream videos over serial ports ?

  


  I also used a kind of Uart to ethernet converter hardware module to solve the problem and hopefully, this worked for me. But the project goal is to send video data over serial ports originally and not using some hardware converters.

  


  Any suggestions would be helpful.

  


• Revision 7066 : suite de suppression des champs pros

  3 novembre 2012, par kent1 — Log

  suite de suppression des champs pros

• Can't isolate pixels from av_frame_copy_to_buffer

  16 septembre 2016, par zzarzzur

  I’m trying to pull the YUV pixel data from an AVFrame, modify the pixels, and put it back into FFmpeg.

  I’m currently using this to retrieve the YUV buffer

  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(base->format);
  
  int baseSize = av_image_get_buffer_size(base->format, base->width, base->height, 32);
  
  uint8_t *baseBuffer = (uint8_t*)malloc(baseSize);
  
  av_image_copy_to_buffer(baseBuffer, baseSize, base->data, base->linesize, base->format, base->width, base->height, 32);

  But I can’t seem to correctly target pixels in that buffer. From the source code they seem to be stacking the planes on top of each other, leading me to attempt this

  int width = base->width;
  
  int height = base->height;
  
  int chroma2h = desc->log2_chroma_h;
  
  int linesizeY = base->linesize[0];
  
  int linesizeU = base->linesize[1];
  
  int linesizeV = base->linesize[2];
  
  int chromaHeight = (height + (1 << chroma2h) -1) >> chroma2h;
  
  
  
  int x = 100;
  
  int y = 100;
  
  
  
  uint8_t *vY = base;
  
  uint8_t *vU = base +(linesizeY*height);
  
  uint8_t *vV = base +((linesizeY*height) + (linesizeU*chromaHeight));
  
  vY+= x + (y * linesizeY);
  
  vU+= x + (y * linesizeU);
  
  vV+= x + (y * linesizeV);

  Using that, if I try to modify pixels from a range of 300,300-400,400 I get a small box darker than the rest of the video, along with horizontal stripes of darkness along the video. The original color is still there, so I think I’m still touching the Y plane on all 3 pointers.

  How can I actually hit the pixels I want to hit ?