From 7f0079dec5da19072cfe64aee233ecacd8ef2ffd Mon Sep 17 00:00:00 2001
From: AlexeyAB <alexeyab84@gmail.com>
Date: Tue, 19 Jun 2018 15:00:36 +0300
Subject: [PATCH] Output video-file has the same FPS as source video-stream.
 Exit from demo by ESC.

---
 src/demo.c          | 21 ++++++++++++++-------
 src/http_stream.cpp | 16 ++++++++++++++++
 src/http_stream.h   |  1 +
 src/image.c         | 12 ++++++++++++
 4 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/src/demo.c b/src/demo.c
index 2ff2343d..6929e087 100644
--- a/src/demo.c
+++ b/src/demo.c
@@ -52,6 +52,7 @@ void draw_detections_cv(IplImage* show_img, int num, float thresh, box *boxes, f
 void draw_detections_cv_v3(IplImage* show_img, detection *dets, int num, float thresh, char **names, image **alphabet, int classes, int ext_output);
 void show_image_cv_ipl(IplImage *disp, const char *name);
 image get_image_from_stream_resize(CvCapture *cap, int w, int h, int c, IplImage** in_img, int cpp_video_capture, int dont_close);
+int get_stream_fps(CvCapture *cap, int cpp_video_capture);
 IplImage* in_img;
 IplImage* det_img;
 IplImage* show_img;
@@ -208,15 +209,17 @@ void demo(char *cfgfile, char *weightfile, float thresh, float hier_thresh, int
 	{
 		CvSize size;
 		size.width = det_img->width, size.height = det_img->height;
+		int src_fps = 25;
+		src_fps = get_stream_fps(cap, cpp_video_capture);
 
 		//const char* output_name = "test_dnn_out.avi";
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('H', '2', '6', '4'), 25, size, 1);
-		output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('D', 'I', 'V', 'X'), 25, size, 1);
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'J', 'P', 'G'), 25, size, 1);
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'P', '4', 'V'), 25, size, 1);
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'P', '4', '2'), 25, size, 1);
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('X', 'V', 'I', 'D'), 25, size, 1);
-		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('W', 'M', 'V', '2'), 25, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('H', '2', '6', '4'), src_fps, size, 1);
+		output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('D', 'I', 'V', 'X'), src_fps, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'J', 'P', 'G'), src_fps, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'P', '4', 'V'), src_fps, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('M', 'P', '4', '2'), src_fps, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('X', 'V', 'I', 'D'), src_fps, size, 1);
+		//output_video_writer = cvCreateVideoWriter(out_filename, CV_FOURCC('W', 'M', 'V', '2'), src_fps, size, 1);
 	}
 
     double before = get_wall_time();
@@ -237,6 +240,10 @@ void demo(char *cfgfile, char *weightfile, float thresh, float hier_thresh, int
 						else if (frame_skip == 60) frame_skip = 4;
 						else frame_skip = 0;
 					}
+					else if (c == 27 || c == 1048603) // ESC - exit (OpenCV 2.x / 3.x)
+					{
+						flag_exit = 1;
+					}
 				}
             }else{
                 char buff[256];
diff --git a/src/http_stream.cpp b/src/http_stream.cpp
index 1b651730..b122f5b7 100644
--- a/src/http_stream.cpp
+++ b/src/http_stream.cpp
@@ -248,6 +248,22 @@ IplImage* get_webcam_frame(CvCapture *cap) {
 	}
 	return src;
 }
+
+int get_stream_fps_cpp(CvCapture *cap) {
+	int fps = 25;
+	try {
+		cv::VideoCapture &cpp_cap = *(cv::VideoCapture *)cap;
+#ifndef CV_VERSION_EPOCH	// OpenCV 3.x
+		fps = cpp_cap.get(CAP_PROP_FPS);
+#else						// OpenCV 2.x
+		fps = cpp_cap.get(CV_CAP_PROP_FPS);
+#endif		
+	}
+	catch (...) {
+		std::cout << " Can't get FPS of source videofile. For output video FPS = 25 by default. \n";
+	}
+	return fps;
+}
 // ----------------------------------------
 extern "C" {
 	image ipl_to_image(IplImage* src);	// image.c
diff --git a/src/http_stream.h b/src/http_stream.h
index 78597a09..bff18fb7 100644
--- a/src/http_stream.h
+++ b/src/http_stream.h
@@ -11,6 +11,7 @@ void send_mjpeg(IplImage* ipl, int port, int timeout, int quality);
 CvCapture* get_capture_webcam(int index);
 CvCapture* get_capture_video_stream(char *path);
 IplImage* get_webcam_frame(CvCapture *cap);
+int get_stream_fps_cpp(CvCapture *cap);
 
 image image_data_augmentation(IplImage* ipl, int w, int h,
 	int pleft, int ptop, int swidth, int sheight, int flip,
diff --git a/src/image.c b/src/image.c
index 53139642..dd0098fb 100644
--- a/src/image.c
+++ b/src/image.c
@@ -1068,6 +1068,18 @@ image get_image_from_stream_resize(CvCapture *cap, int w, int h, int c, IplImage
 	return im;
 }
 
+int get_stream_fps(CvCapture *cap, int cpp_video_capture)
+{
+	int fps = 25;
+	if (cpp_video_capture) {
+		fps = get_stream_fps_cpp(cap);
+	}
+	else {
+		fps = cvGetCaptureProperty(cap, CV_CAP_PROP_FPS);
+	}
+	return fps;
+}
+
 void save_image_jpg(image p, const char *name)
 {
     image copy = copy_image(p);