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119 lines
3.6 KiB
C++
119 lines
3.6 KiB
C++
/**
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@file videowriter.cpp
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@brief A sample for VideoWriter and VideoCapture with options to specify video codec, fps and resolution
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@date April 05, 2024
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*/
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#include <opencv2/core.hpp>
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#include <opencv2/videoio.hpp>
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#include <opencv2/highgui.hpp>
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#include <opencv2/imgproc.hpp>
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#include <iostream>
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#include <map>
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using namespace cv;
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using namespace std;
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inline map<string, int> fourccByCodec() {
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map<string, int> res;
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res["h264"] = VideoWriter::fourcc('H', '2', '6', '4');
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res["h265"] = VideoWriter::fourcc('H', 'E', 'V', 'C');
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res["mpeg2"] = VideoWriter::fourcc('M', 'P', 'E', 'G');
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res["mpeg4"] = VideoWriter::fourcc('M', 'P', '4', '2');
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res["mjpeg"] = VideoWriter::fourcc('M', 'J', 'P', 'G');
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res["vp8"] = VideoWriter::fourcc('V', 'P', '8', '0');
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return res;
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}
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// Function to parse resolution string "WxH"
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static Size parseResolution(const string& resolution) {
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stringstream ss(resolution);
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int width, height;
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char delimiter;
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ss >> width >> delimiter >> height;
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if (ss.fail() || delimiter != 'x') {
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throw runtime_error("Invalid resolution format. Please provide in WxH format.");
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}
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return Size(width, height);
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}
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int main(int argc, char** argv) {
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const String keys =
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"{help h usage ? | | Print help message }"
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"{fps |30 | fix frame per second for encoding (supported: fps > 0) }"
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"{codec |mjpeg | Supported codecs depend on OpenCV Configuration. Try one of 'h264', 'h265', 'mpeg2', 'mpeg4', 'mjpeg', 'vp8' }"
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"{resolution |1280x720 | Video resolution in WxH format, (e.g., '1920x1080') }"
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"{output_filepath | output.avi | Path to the output video file}";
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CommandLineParser parser(argc, argv, keys);
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parser.about("Video Capture and Write with codec and resolution options");
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if (parser.has("help")) {
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parser.printMessage();
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return 0;
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}
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double fps = parser.get<double>("fps");
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string codecStr = parser.get<string>("codec");
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string resolutionStr = parser.get<string>("resolution");
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string outputFilepath = parser.get<string>("output_filepath");
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auto codecMap = fourccByCodec();
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if (codecMap.find(codecStr) == codecMap.end()) {
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cerr << "Invalid codec" << endl;
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return -1;
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}
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int codec = codecMap[codecStr];
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Size resolution = parseResolution(resolutionStr);
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// Video Capture
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VideoCapture cap(0);
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if (!cap.isOpened()) {
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cerr << "ERROR! Unable to open camera\n";
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return -1;
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}
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cout << "Selected FPS: " << fps << endl;
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cout << "Selected Codec: " << codecStr << endl;
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cout << "Selected Resolution: " << resolutionStr << " (" << resolution.width << "x" << resolution.height << ")" << endl;
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// Set up VideoWriter
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VideoWriter writer(outputFilepath, codec, fps, resolution, true); // Assuming color video
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if (!writer.isOpened()) {
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cerr << "Could not open the output video file for write\n";
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return -1;
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}
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cout << "Writing video file: " << outputFilepath << endl
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<< "Press any key to terminate" << endl;
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Mat frame, resizedFrame;
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for (;;) {
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// Capture frame
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if (!cap.read(frame) || frame.empty()) {
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break;
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}
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// Resize frame to desired resolution
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resize(frame, resizedFrame, resolution);
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// Write resized frame to video
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writer.write(resizedFrame);
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// Show live
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imshow("Live", resizedFrame);
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if (waitKey(5) >= 0) break;
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}
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// VideoWriter and VideoCapture are automatically closed by their destructors
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return 0;
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}
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