Jetson xavier nx 入门系列——c++调用opencv，读取rtsp视频流

1、问题检索

用pkg-config --modversion opencv命令，查看opencv版本，提示找不到

Package opencv was not found in the pkg-config search path.
Perhaps you should add the directory containing `opencv.pc'
to the PKG_CONFIG_PATH environment variable
No package 'opencv' found

报错原因：是因为没有找到opencv.pc，而刷机时是安装了OpenCV的，不过是OpenCV4，在/usr/lib/aarch64-linux-gnu/pkgconfig中找到了opencv4.pc

2、解决方案

采用如下命令查看nx板中opencv版本,可知为opencv4

dpkg -l libopencv

将pkg-config的命令修改为opencv4即可正常使用

pkg-config --modversion opencv4

3、C++使用opencv，并正确编译的方法

3.1 读取rtsp视频流示例

#include "opencv2\opencv.hpp"
#include <iostream>

using namespace cv;

int main()
{

  VideoCapture capture;
  //capture.open("../../bin/data/1.mp4");
  capture.open("rtsp://admin:admin123@192.168.1.164:554/cam/realmonitor?channel=1&subtype=0");

  int frameH = capture.get(4);
  int frameW = capture.get(3);
  std::cout << "frameH:" << frameH << "  frameW:" << frameW << std::endl;

  while (1)
  {
      Mat frame;
      capture >> frame;
      
      if (frame.empty())
      {
          break;
      }
      imshow("test", frame);
      waitKey(30);
  }
}

3.2 编译代码

方法一：直接进行命令行编译

注意，此处要写为opencv4

g++ -o Main capture_video.cpp `pkg-config opencv4 --libs --cflags`

方法二：编写CMakeLists.txt进行编译

1. 编写CMakeLists.txt，内容如下

cmake_minimum_required(VERSION 2.8)

find_package(OpenCV)
include_directories(OpenCV_INCLUDE_DIRS)
message(${OpenCV_INCLUDE_DIRS})
message(${OpenCV_LIBRARIES})

add_definitions("-Wall -std=c++11")
add_executable(Main capture_video.cpp)

target_link_libraries(Main ${OpenCV_LIBRARIES})

2. 开始编译，命令如下

mkdir build
cd build
cmake ..
make

参考文献

1. Jetson AGX Xavier配置使用OpenCV（报错：No package ‘opencv’ found）
2. opencv RTSP拉流