1. 相关知识点

VideoCapture；

applyColorMap；

VideoWriter；

2. 代码

编写代码main.cpp:

#include<iostream>
#include "opencv2/opencv.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"using namespace cv;void videoRW(String video_path, String out_path) {std::cout << video_path << std::endl;std::cout << out_path << std::endl;VideoCapture video(video_path);if (!video.isOpened()){std::cout << "Read Video Error!" << std::endl;return;}int width = cvRound(video.get(CAP_PROP_FRAME_WIDTH));int higth = cvRound(video.get(CAP_PROP_FRAME_HEIGHT));std::cout << "Weight: " << width << std::endl;std::cout << "Height: " << higth << std::endl;std::cout << "FPS: " << video.get(CAP_PROP_FPS) << std::endl;std::cout << "Frame num: " << video.get(CAP_PROP_FRAME_COUNT) << std::endl;VideoWriter writer(out_path, video.get(CAP_PROP_FOURCC), video.get(CAP_PROP_FPS),Size(width*2, higth));Mat frame, dst;int index = 0;while (true) {video.read(frame);if (frame.empty()){break;}index++;applyColorMap(frame, dst, cvRound(index/10) % 21);Mat big(higth, width * 2, CV_8UC3);frame.copyTo(big(Rect(0, 0, width, higth)));dst.copyTo(big(Rect(width, 0, width, higth)));String wname = "video";namedWindow(wname, 0);imshow(wname, big);writer.write(big);int key = waitKey(10);if (key == 27) {break;}}video.release();writer.release();
}int main(int argc, char **argv)
{std::cout << "arg count: " << argc << "\narg value: " << argv << std::endl;std::cout << "video demo~" << std::endl;const String video_path = argv[1];String out_path = argv[2];videoRW(video_path, out_path);cv::destroyAllWindows();std::cout<<"\n------Demo Over!------\n"<<std::endl;return 0;
}

编写CmakeLists.txt:

# cmake needs this line
cmake_minimum_required(VERSION 3.1)# Define project name
project(opencv_example_project)# Find OpenCV, you may need to set OpenCV_DIR variable
# to the absolute path to the directory containing OpenCVConfig.cmake file
# via the command line or GUI
find_package(OpenCV REQUIRED)# If the package has been found, several variables will
# be set, you can find the full list with descriptions
# in the OpenCVConfig.cmake file.
# Print some message showing some of them
message(STATUS "OpenCV library status:")
message(STATUS "    config: ${OpenCV_DIR}")
message(STATUS "    version: ${OpenCV_VERSION}")
message(STATUS "    libraries: ${OpenCV_LIBS}")
message(STATUS "    include path: ${OpenCV_INCLUDE_DIRS}")aux_source_directory(. ALL_SRCS)# Declare the executable target built from your sources
add_executable(demo ${ALL_SRCS})# Link your application with OpenCV libraries
target_link_libraries(demo PRIVATE ${OpenCV_LIBS})

编译并执行：

# 编译
mkdir build
cd build
cmake ..
make# 运行：需指定输入视频的路径和视频保存的路径
./demo input.mp4 output.mp4

3. 效果展示