convert_dfe.cpp

/*
 * Dual-fisheye 形式の動画を横長の動画にして出力するプログラム
 *
 * コンパイル:
 * $ g++ convert_dfe.cpp `pkg-config opencv --cflags --libs` -std=c++11 -O3 -o convert_dfe
 *
 * 使い方:
 * $ convert_dfe 入力動画パス 出力動画パス
 */

#include <iostream>
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/features2d.hpp"
#define _USE_MATH_DEFINES
#include <cmath>
#include <chrono>


using namespace cv;


//// 設定 ////

// 出力動画のFPS
const static double fps = 29.97;

// 一つの魚眼のマップ先のサイズ この数値を上げると出力動画の解像度が上がる
const static int mapped_size = 640;

// 出力動画の上下の切り取りサイズ
const static int trim_size = mapped_size / 4;

// 出力動画サイズ ここは変えちゃダメ
const static Size output_size(mapped_size * 2, mapped_size - trim_size * 2);

//////////////


int main(int argc, char *argv[]) {

	if (argc <= 2) {
		std::cout << "Please call me as following: $ " << argv[0] << " input_movie.mp4 output_movie.mp4" << std::endl;
		return 0;
	}

	std::cout << "input: " << argv[1] << std::endl;
	std::cout << "output: " << argv[2] << std::endl;

	VideoCapture video(argv[1]);

	// CV_FOURCC で出力動画のコーデックを指定しています
	// ここを参照: https://gist.github.com/takuma7/44f9ecb028ff00e2132e
	// 大文字小文字区別するようなので注意
	VideoWriter writer(argv[2], CV_FOURCC('m','p','4','v'), fps, output_size, true);

	// プレビュー用ウィンドウ
	//cv::namedWindow("movie");

	Mat img(output_size.height, output_size.width, CV_8UC3);

	auto lastTime = std::chrono::system_clock::now();

	for (int frame_count = 0; ; ++frame_count) {
		// 進捗を表示
		if (frame_count % 100 == 0) {
			auto elapsedTime = std::chrono::duration_cast<std::chrono::milliseconds>
				(std::chrono::system_clock::now() - lastTime).count();
			std::cout << "current frame: " << frame_count
								<< ", elapsed: " << elapsedTime << " ms"
								<< std::endl;
			lastTime = std::chrono::system_clock::now();
		}

		Mat frame(1080, 1920, CV_8UC3);

		video >> frame;

		//if (frame.empty() || waitKey(30) >= 0 || video.get(CV_CAP_PROP_POS_AVI_RATIO) == 1) {
		if (frame.empty() || video.get(CV_CAP_PROP_POS_AVI_RATIO) == 1) {
			break;
		}

		auto frame_data = frame.data;
		auto img_data = img.data;
		int frame_step = frame.step;
		int img_step = img.step;
		int frame_elemSize = frame.elemSize();
		int img_elemSize = img.elemSize();
		for (int y = trim_size; y < mapped_size - trim_size; ++y) {
			for (int x = 0; x < mapped_size; ++x) {
				double ax = static_cast<double>(y - mapped_size / 2) / mapped_size;
				double ay = static_cast<double>(x - mapped_size / 2) / mapped_size;
				double cx = std::sin(ax * M_PI);
				double cy = std::sin(ay * M_PI);

				int lsx = std::round(cx * 428) + 480;
				int lsy = std::round(-cy * std::cos(ax * M_PI) * 428) + 480;
				int rsx = std::round(-cx * 428) + 1440;
				int rsy = std::round(cy * std::cos(ax * M_PI) * 428) + 480;

				for (int c = 0; c < 3; ++c)
					img_data[(y - trim_size) * img_step + x * img_elemSize + c] =
						frame_data[lsy * frame_step + lsx * frame_elemSize + c];
				for (int c = 0; c < 3; ++c)
					img_data[(y - trim_size) * img_step + (x + mapped_size) * img_elemSize + c] =
						frame_data[rsy * frame_step + rsx * frame_elemSize + c];
				// ↑for 文を2つに分けると早い (ループ展開 が効いてる？)

				/*
				{ // 左半分
					double ax = static_cast<double>(y - mapped_size / 2) / mapped_size;
					double ay = -static_cast<double>(x - mapped_size / 2) / mapped_size;
					double cx = std::sin(ax * M_PI);
					double cy = std::sin(ay * M_PI);
					int sx = std::round(cx * 428) + 480;
					int sy = std::round(cy * std::cos(ax * M_PI) * 428) + 480;
					for (int c = 0; c < 3; ++c)
						img_data[(y - trim_size) * img.step + x * img.elemSize() + c] =
							frame_data[sy * frame.step + sx * frame.elemSize() + c];
				}
				{ // 右半分
					double ax = -static_cast<double>(y - mapped_size / 2) / mapped_size;
					double ay = static_cast<double>(x - mapped_size / 2) / mapped_size;
					double cx = std::sin(ax * M_PI);
					double cy = std::sin(ay * M_PI);
					int sx = std::round(cx * 428) + 1440;
					int sy = std::round(cy * std::cos(ax * M_PI) * 428) + 480;
					for (int c = 0; c < 3; ++c)
						img_data[(y - trim_size) * img.step + (x + mapped_size) * img.elemSize() + c] =
							frame_data[sy * frame.step + sx * frame.elemSize() + c];
				}//*/
			}
		}

		writer << img;

		// プレビュー
		//waitKey(1);
		//imshow("movie", img);
	}

	std::cout << std::endl << "done." << std::endl;

	return 0;
}