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• Open USB camera with OpenCV and stream to rtsp server

  12 septembre 2017, par user2594166

  I got a Logitech C920 camera connected via USB to a NVIDIA TX1. I am trying to both stream the camera feed over rtsp to a server while doing some computer vision in OpenCV. I managed to read H264 video from the usb camera in Opencv

  #include <iostream>
  
  #include "opencv/cv.h"
  
  #include <opencv2></opencv2>opencv.hpp>
  
  #include "opencv/highgui.h"
  
  
  
  using namespace cv;
  
  using namespace std;
  
  
  
  int main()
  
  {
  
      Mat img;
  
      VideoCapture cap;
  
      int heightCamera = 720;
  
      int widthCamera = 1280;
  
  
  
      // Start video capture port 0
  
      cap.open(0);
  
  
  
  
  
      // Check if we succeeded
  
      if (!cap.isOpened())
  
      {
  
          cout &lt;&lt; "Unable to open camera" &lt;&lt; endl;
  
          return -1;
  
      }
  
      // Set frame width and height
  
      cap.set(CV_CAP_PROP_FRAME_WIDTH, widthCamera);
  
      cap.set(CV_CAP_PROP_FRAME_HEIGHT, heightCamera);
  
      cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('X','2','6','4'));
  
  
  
      // Set camera FPS
  
      cap.set(CV_CAP_PROP_FPS, 30);
  
  
  
      while (true)
  
      {
  
          // Copy the current frame to an image
  
          cap >> img;
  
  
  
          // Show video streams
  
          imshow("Video stream", img);
  
  
  
          waitKey(1);
  
      }
  
  
  
      // Release video stream
  
      cap.release();
  
  
  
      return 0;
  
  }
  
  </iostream>

  I also have streamed the USB camera to a rtsp server by using ffmpeg :
  ffmpeg -f v4l2 -input_format h264 -timestamps abs -video_size hd720 -i /dev/video0 -c:v copy -c:a none -f rtsp rtsp://10.52.9.104:45002/cameraTx1

  I tried to google how to combine this two functions, i.e. open usb camera in openCV and use openCV to stream H264 rtsp video. However, all I can find is people trying to open rtsp stream in openCV.

  Have anyone successfully stream H264 rtsp video using openCV with ffmpeg ?

  Best regards
  Sondre

• opencv V3 mixing shared and non shared

  31 décembre 2015, par Kellerspeicher

  The current stable (V3.0.0) and unstable (V3.1.0) version of openCV is mixing shared and non shared libraries if compiled on an Ubuntu 14.04.3 LTS.

  Linking CXX shared library ../../lib/libopencv_videoio.so
  
  /usr/bin/ld: /usr/local/lib/libavcodec.a(avpacket.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
  
  /usr/local/lib/libavcodec.a: error adding symbols: Bad value
  
  collect2: error: ld returned 1 exit status
  
  make[2]: *** [lib/libopencv_videoio.so.3.1.0] Error 1
  
  make[1]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2
  
  make: *** [all] Error 2

  Trying to create libopencv_videoio.so using libavcodec.a seems to be the problem. There is a bug report about that, but it is only giving the advice to check if libavcodec.so is installed (which is) and a workaround to use -DBUILD_SHARED_LIBS=OFF to prevent creation of shared libraries. Does anyone knows the reason for this problem. The openCV people just state the Ubuntu packaged ffmpeg library to be not correct. Any idea ?

  The problem seems to be old. I just found a very similar question not answered but commented with the advice of compiling ffmpeg with ./configure --enable-shared. But there is already a shared library /usr/lib/x86_64-linux-gnu/libavcodec.so which obviously is not found. I am not a cmake expert but couldn’t it be a problem of a miss leaded build process ?

• Merge commit ’b704b648f9ecb830874627db958a37e004107d1b’

  8 décembre 2014, par Michael Niedermayer

  Merge commit ’b704b648f9ecb830874627db958a37e004107d1b’
  * commit ’b704b648f9ecb830874627db958a37e004107d1b’ :
  
    mov : parse XMP metadata on demand
  Conflicts :
  
  	libavformat/isom.h
  
  	libavformat/version.h
  See : 054c506e3da35471ea92dbedcaaf720d0754f04e
  The default is left unchanged at enabled
  
  We can change the default if people prefer but i do not want to do that
  
  in a merge.
  Merged-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/isom.h
  • [DH] libavformat/mov.c
  • [DH] libavformat/version.h