124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
/**
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* @file opencv_fb.cpp
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* Displays OpenCV video on framebuffer.
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* Compile with
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* g++ -o fbwrite_video -lopencv_core -lopencv_highgui -lopencv_imgproc fbwrite_video.cpp
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*
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* Contains code from https://stackoverflow.com/questions/4722301/writing-to-frame-buffer
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*/
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#include <iostream> // for cerr
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#include <opencv2/imgproc/imgproc.hpp> // for cvtColor
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#include <opencv2/highgui/highgui.hpp> // for VideoCapture
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#include <fstream> // for ofstream
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#include <boost/timer/timer.hpp> // for boost::timer::cpu_timer
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using namespace std;
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using namespace cv;
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// this is C :/
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#include <stdint.h> // for uint32_t
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#include <sys/ioctl.h> // for ioctl
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#include <linux/fb.h> // for fb_
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#include <fcntl.h> // for O_RDWR
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struct framebuffer_info {
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uint32_t bits_per_pixel;
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uint32_t xres_virtual;
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uint32_t yres_virtual;
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};
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struct framebuffer_info get_framebuffer_info(const char* framebuffer_device_path) {
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struct framebuffer_info info;
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struct fb_var_screeninfo screen_info;
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int fd = -1;
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fd = open(framebuffer_device_path, O_RDWR);
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if (fd >= 0) {
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if (!ioctl(fd, FBIOGET_VSCREENINFO, &screen_info)) {
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info.xres_virtual = screen_info.xres_virtual;
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info.yres_virtual = screen_info.yres_virtual;
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info.bits_per_pixel = screen_info.bits_per_pixel;
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}
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}
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return info;
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};
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// C ends here
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void display (Mat frame, framebuffer_info fb_info, ofstream& ofs) {
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if (frame.depth() != CV_8U) {
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cerr << "Not 8 bits per pixel and channel." << endl;
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} else if (frame.channels() != 3) {
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cerr << "Not 3 channels." << endl;
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} else {
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// 3 Channels (assumed BGR), 8 Bit per Pixel and Channel
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int framebuffer_width = fb_info.xres_virtual;
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int framebuffer_depth = fb_info.bits_per_pixel;
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Size2f frame_size = frame.size();
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Mat framebuffer_compat;
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switch (framebuffer_depth) {
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case 16:
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cvtColor(frame, framebuffer_compat, COLOR_BGR2BGR565);
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for (int y = 0; y < frame_size.height ; y++) {
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ofs.seekp(y*framebuffer_width*2);
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ofs.write(reinterpret_cast<char*>(framebuffer_compat.ptr(y)),frame_size.width*2);
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}
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break;
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case 32: {
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vector<Mat> split_bgr;
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split(frame, split_bgr);
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split_bgr.push_back(Mat(frame_size,CV_8UC1,Scalar(255)));
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merge(split_bgr, framebuffer_compat);
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for (int y = 0; y < frame_size.height ; y++) {
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ofs.seekp(y*framebuffer_width*4);
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ofs.write(reinterpret_cast<char*>(framebuffer_compat.ptr(y)),frame_size.width*4);
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}
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} break;
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default:
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cerr << "Unsupported depth of framebuffer: " << framebuffer_depth << endl;
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}
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}
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}
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Mat frameEffects (Mat frame) {
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Mat grey;
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Mat contrast;
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Mat blur;
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Mat flipper;
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//flip(frame, flipper, 1);
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//cvtColor(flipper, grey, COLOR_BGR2GRAY);
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//grey.convertTo(contrast, -1, 1, 0);
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//cvtColor(contrast, frame, COLOR_GRAY2BGR);
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return frame;
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}
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int main(int, char**) {
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const int frame_rate = 24;
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int frameCount = 0;
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framebuffer_info fb_info = get_framebuffer_info("/dev/fb0");
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VideoCapture cap(0);
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if(!cap.isOpened()) {
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cerr << "Could not open video device." << endl;
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return 1;
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} else {
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cout << "Successfully opened video device." << endl;
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cap.set(CAP_PROP_FRAME_WIDTH, 1280);
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cap.set(CAP_PROP_FRAME_HEIGHT, 720);
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cap.set(CAP_PROP_FPS, frame_rate);
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//cap.set(CAP_PROP_BUFFERSIZE,3);
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cout << cap.get(CAP_PROP_FRAME_WIDTH) << "x" << cap.get(CAP_PROP_FRAME_HEIGHT) << endl;
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ofstream ofs("/dev/fb0");
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Mat frame;
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Mat displayFrame;
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while (true) {
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cap >> frame;
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if (frame.empty()) {
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continue;
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}
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frame = frameEffects(frame);
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resize(frame, displayFrame, Size(fb_info.xres_virtual, fb_info.yres_virtual), 2, 2, INTER_CUBIC);
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display(displayFrame, fb_info, ofs);
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waitKey(42);
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}
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}
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}
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