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squashed #823

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removed separate example for reading image sequences and modified starter_video.cpp to better explain the functionality of VideoCapture. I also added a bit more explanation in the documentation of the VideoCapture interface

Conflicts:
	modules/highgui/doc/reading_and_writing_images_and_video.rst
	samples/cpp/starter_video.cpp

starter_video.cpp changed CV WINDOW KEEPRATIO to just WINDOW KEEPTATIO to fix build error

starter_video.cpp hid local functions
This commit is contained in:
Kevin Hughes 2013-04-17 13:20:32 -04:00 committed by Dikay900
parent 5c6c537044
commit ac3ec0d96d
2 changed files with 37 additions and 32 deletions
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4
modules/highgui/doc/reading_and_writing_images_and_video.rst
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@ -193,8 +193,8 @@ VideoCapture
------------
.. ocv:class:: VideoCapture
Class for video capturing from video files or cameras.
The class provides C++ API for capturing video from cameras or for reading video files. Here is how the class can be used: ::
Class for video capturing from video files, image sequences or cameras.
The class provides C++ API for capturing video from cameras or for reading video files and image sequences. Here is how the class can be used: ::
#include "opencv2/opencv.hpp"

65
samples/cpp/starter_video.cpp
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@ -4,31 +4,34 @@
* Created on: Nov 23, 2010
* Author: Ethan Rublee
*
* A starter sample for using opencv, get a video stream and display the images
* Modified on: April 17, 2013
* Author: Kevin Hughes
*
* A starter sample for using OpenCV VideoCapture with capture devices, video files or image sequences
* easy as CV_PI right?
*/
#include "opencv2/highgui/highgui.hpp"
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <vector>
#include <stdio.h>
using namespace cv;
using namespace std;
//hide the local functions in an anon namespace
namespace {
void help(char** av) {
cout << "\nThis program justs gets you started reading images from video\n"
"Usage:\n./" << av[0] << " <video device number>\n"
<< "q,Q,esc -- quit\n"
<< "space -- save frame\n\n"
<< "\tThis is a starter sample, to get you up and going in a copy pasta fashion\n"
<< "\tThe program captures frames from a camera connected to your computer.\n"
<< "\tTo find the video device number, try ls /dev/video* \n"
<< "\tYou may also pass a video file, like my_vide.avi instead of a device number"
<< endl;
cout << "The program captures frames from a video file, image sequence (01.jpg, 02.jpg ... 10.jpg) or camera connected to your computer." << endl
<< "Usage:\n" << av[0] << " <video file, image sequence or device number>" << endl
<< "q,Q,esc -- quit" << endl
<< "space -- save frame" << endl << endl
<< "\tTo capture from a camera pass the device number. To find the device number, try ls /dev/video*" << endl
<< "\texample: " << av[0] << " 0" << endl
<< "\tYou may also pass a video file instead of a device number" << endl
<< "\texample: " << av[0] << " video.avi" << endl
<< "\tYou can also pass the path to an image sequence and OpenCV will treat the sequence just like a video." << endl
<< "\texample: " << av[0] << " right%%02d.jpg" << endl;
}
int process(VideoCapture& capture) {
@ -36,31 +39,33 @@ namespace {
char filename[200];
string window_name = "video | q or esc to quit";
cout << "press space to save a picture. q or esc to quit" << endl;
namedWindow(window_name, CV_WINDOW_KEEPRATIO); //resizable window;
namedWindow(window_name, WINDOW_NORMAL); //resizable window;
Mat frame;
for (;;) {
capture >> frame;
if (frame.empty())
break;
imshow(window_name, frame);
char key = (char)waitKey(5); //delay N millis, usually long enough to display and capture input
char key = (char)waitKey(30); //delay N millis, usually long enough to display and capture input
switch (key) {
case 'q':
case 'Q':
case 27: //escape key
return 0;
case ' ': //Save an image
sprintf(filename,"filename%.3d.jpg",n++);
imwrite(filename,frame);
cout << "Saved " << filename << endl;
break;
default:
break;
case 'q':
case 'Q':
case 27: //escape key
return 0;
case ' ': //Save an image
sprintf(filename,"filename%.3d.jpg",n++);
imwrite(filename,frame);
cout << "Saved " << filename << endl;
break;
default:
break;
}
}
return 0;
}
}
int main(int ac, char** av) {
@ -70,11 +75,11 @@ int main(int ac, char** av) {
return 1;
}
std::string arg = av[1];
VideoCapture capture(arg); //try to open string, this will attempt to open it as a video file
VideoCapture capture(arg); //try to open string, this will attempt to open it as a video file or image sequence
if (!capture.isOpened()) //if this fails, try to open as a video camera, through the use of an integer param
capture.open(atoi(arg.c_str()));
if (!capture.isOpened()) {
cerr << "Failed to open a video device or video file!\n" << endl;
cerr << "Failed to open the video device, video file or image sequence!\n" << endl;
help(av);
return 1;
}