From 455b2fc06ff590914f3a1fb13261510d2b95de2e Mon Sep 17 00:00:00 2001
From: AlexeyAB <alexeyab84@gmail.com>
Date: Thu, 21 Jun 2018 14:45:43 +0300
Subject: [PATCH] Able letterbox for video

---
 src/demo.c  | 14 +++++++++++---
 src/image.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/src/demo.c b/src/demo.c
index 6929e0870e1..34627ce1fa9 100644
--- a/src/demo.c
+++ b/src/demo.c
@@ -52,18 +52,23 @@ 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);
+image get_image_from_stream_letterbox(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;
 
 static int flag_exit;
+static int letter_box = 0;
 
 void *fetch_in_thread(void *ptr)
 {
     //in = get_image_from_stream(cap);
 	int dont_close_stream = 0;	// set 1 if your IP-camera periodically turns off and turns on video-stream
-	in_s = get_image_from_stream_resize(cap, net.w, net.h, net.c, &in_img, cpp_video_capture, dont_close_stream);
+	if(letter_box) 
+		in_s = get_image_from_stream_letterbox(cap, net.w, net.h, net.c, &in_img, cpp_video_capture, dont_close_stream);
+	else
+		in_s = get_image_from_stream_resize(cap, net.w, net.h, net.c, &in_img, cpp_video_capture, dont_close_stream);
     if(!in_s.data){
         //error("Stream closed.");
 		printf("Stream closed.\n");
@@ -89,9 +94,12 @@ void *detect_in_thread(void *ptr)
 
     free_image(det_s);
 
-	int letter = 0;
 	int nboxes = 0;
-	detection *dets = get_network_boxes(&net, det_s.w, det_s.h, demo_thresh, demo_thresh, 0, 1, &nboxes, letter);
+	detection *dets = NULL;
+	if (letter_box)
+		dets = get_network_boxes(&net, in_img->width, in_img->height, demo_thresh, demo_thresh, 0, 1, &nboxes, 1); // letter box
+	else
+		dets = get_network_boxes(&net, det_s.w, det_s.h, demo_thresh, demo_thresh, 0, 1, &nboxes, 0); // resized
 	//if (nms) do_nms_obj(dets, nboxes, l.classes, nms);	// bad results
 	if (nms) do_nms_sort(dets, nboxes, l.classes, nms);
 	
diff --git a/src/image.c b/src/image.c
index dd0098fbeae..a2dc3cacd80 100644
--- a/src/image.c
+++ b/src/image.c
@@ -1068,6 +1068,37 @@ image get_image_from_stream_resize(CvCapture *cap, int w, int h, int c, IplImage
 	return im;
 }
 
+image get_image_from_stream_letterbox(CvCapture *cap, int w, int h, int c, IplImage** in_img, int cpp_video_capture, int dont_close)
+{
+	c = c ? c : 3;
+	IplImage* src;
+	if (cpp_video_capture) {
+		static int once = 1;
+		if (once) {
+			once = 0;
+			do {
+				src = get_webcam_frame(cap);
+				if (!src) return make_empty_image(0, 0, 0);
+			} while (src->width < 1 || src->height < 1 || src->nChannels < 1);
+			printf("Video stream: %d x %d \n", src->width, src->height);
+		}
+		else
+			src = get_webcam_frame(cap);
+	}
+	else src = cvQueryFrame(cap);
+
+	if (cpp_video_capture)
+		if (!wait_for_stream(cap, src, dont_close)) return make_empty_image(0, 0, 0);
+	*in_img = cvCreateImage(cvSize(src->width, src->height), IPL_DEPTH_8U, c);
+	cvResize(src, *in_img, CV_INTER_LINEAR);
+	image tmp = ipl_to_image(src);
+	image im = letterbox_image(tmp, w, h);
+	free_image(tmp);
+	if (cpp_video_capture) cvReleaseImage(&src);
+	if (c>1) rgbgr_image(im);
+	return im;
+}
+
 int get_stream_fps(CvCapture *cap, int cpp_video_capture)
 {
 	int fps = 25;