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• PyAV Raw video to MJPEG or RTSP

  14 décembre 2020, par aris-t

  I figured I would ask this in parallel to my own searching as I am not that familiar with ffmpeg or PyAV.

  


  How might one go about reading raw video from a webcam, trans code it to either Mjpeg or RTSP and output it using PyAV ?

  


  I find plenty of examples of reading one file to another of the same format, reading RTSP and MJPEG to a file but no examples raw video to stream. My attempts at taking the raw video to file have also been unsuccessful resulting in data being written to the file yet the file is non readable and appears to have indexing issues.

  


  Any help is appreciated.

  


• Get RGB values from AVPicture and change to grey-scale in FFMPEG

  22 octobre 2014, par user2742299

  The main motive of my code is to change the RGB values from the AVPicture in FFMPEG.

  I have been able to get the image data "data[0]" by following the article : http://blog.tomaka17.com/2012/03/libavcodeclibavformat-tutorial/

  I would like to know that how can I access the 3 bytes of pic.data[0] which is in RGB format. I have been trying to access the pic.data[i][j] via for-loop in 2D matrix fashion but jth element>3.

  Any guidance in this regard will be helpful.

  Code is here :

  AVPicture pic;
  
          avpicture_alloc(&pic, PIX_FMT_RGB24, mpAVFrameInput->width,mpAVFrameInput->height);
  
          auto ctxt = sws_getContext(mpAVFrameInput->width,mpAVFrameInput->height,static_cast<pixelformat>(mpAVFrameInput->format),
  
              mpAVFrameInput->width, mpAVFrameInput->height, PIX_FMT_RGB24, SWS_BILINEAR, nullptr, nullptr, nullptr);
  
  
  
          if (ctxt == nullptr)
  
              throw std::runtime_error("Error while calling sws_getContext");
  
          sws_scale(ctxt, mpAVFrameInput->data, mpAVFrameInput->linesize, 0, mpAVFrameInput->height, pic.data,
  
              pic.linesize);
  
  
  
  
  
      for (int i = 0; i &lt; (mpAVFrameInput->height-1); i++) {
  
  
  
          for (int j = 0;  j &lt; (mpAVFrameInput->width-1); j++) {
  
          printf("\n value: %d",pic.data[0][j]);
  
  
  
          }
  
  
  
      }
  
  </pixelformat>

  Pseudo code which is in my mind is :

  For each pixel in image {
  
  Red = pic.data[i][j].pixel.RED;
  
  Green = pic.data[i][j].pixel.GREEN;
  
  Blue = pic.data[i][j].pixel.BLUE;
  
  GRAY = (Red+Green+Blue)/3;
  
  Red = GRAY;
  
  Green = GRAY;
  
  Blue = GRAY;
  
  Save Frame;}

  I am quite new to FFMPEG therefore any guidance and help will be highly appreciable.

  Many Thanks

• Two rtsp streams to youtube on a Pi3

  19 mars 2020, par Sébastien Bonaimé

  I want to stream two rtsp camera from my birdbox to youtube from my raspberry pi 3 with the entrance in Pip (picture in picture) on top left. I don’t need sound.

  192.168.1.13 can do 30 fps with sound that I don’t need
  192.168.1.31 is only 12 fps without sound

  I have some problems of lag between the two camera on the youtube stream which I think is due to the different fps. I compile ffmpeg with h264. Here is what I did

  ffmpeg -re -f lavfi -i anullsrc -rtsp_transport udp -thread_queue_size 1000k -i rtsp://admin:123@192.168.1.13:554 -i rtsp://admin:@192.168.1.31:554 -filter_complex "[1]scale=iw/4:ih/4[pip]; [2][pip] overlay=0:0"   -framerate 13  -bufsize 512k  -b:v 1500k -threads 4 -q:v 3  -c:v h264_omx  -c:a aac -f flv rtmp://a.rtmp.youtube.com/live2/XXX-XXXX-XXX

  and here are the errors

  [h264 @ 0x20ddd30] error while decoding MB 69 67, bytestream -6rate=1589.2kbits/s dup=0 drop=6 speed=0.997x
  
  [h264 @ 0x20ddd30] concealing 100 DC, 100 AC, 100 MV errors in I frame
  
  rtsp://admin:@192.168.1.31:554: corrupt decoded frame in stream 0te=1589.0kbits/s dup=0 drop=6 speed=0.997x
  
  [rtsp @ 0x1f2cea0] max delay reached. need to consume packetbitrate=1589.2kbits/s dup=0 drop=6 speed=0.997x
  
  [rtsp @ 0x1f2cea0] RTP: missed 35 packets
  
  [h264 @ 0x2099580] error while decoding MB 60 30, bytestream -6rate=1589.3kbits/s dup=0 drop=6 speed=0.997x
  
  [h264 @ 0x2099580] concealing 4549 DC, 4549 AC, 4549 MV errors in I frame
  
  rtsp://admin:@192.168.1.31:554: corrupt decoded frame in stream 0
  
  [rtsp @ 0x1f2cea0] max delay reached. need to consume packetbitrate=1588.9

  What can I do to improve the stream ? When a bird enter the box, there is also a quality problem when the image is changing and some lagging.
  You can have a look here
  https://www.youtube.com/watch?v=iisbinyvSFk&feature=youtu.be

  Thank you