OpenCV play video

During school days when i use OpenCV 1.1-2.0 for my final year project,

I had a hard time trying to capture video frame from .avi files.

I ran into codec issues having to convert my video dataset before i can capture

via OpenCV.

With the following code snippets below i am able to play .avi,.mpg and wmv files!

#include "highgui.h"
int main( int argc, char** argv ) {
  
    //Some validation can be included here for argv
    if( argc<2 ) return 1;
    CvCapture* capture = cvCreateFileCapture( argv[1] );
    if( !capture ) return 1;   
     /* get fps, needed to set the delay */
    int fps = ( int )cvGetCaptureProperty( capture, CV_CAP_PROP_FPS );
    IplImage* frame;
    cvNamedWindow( "video", CV_WINDOW_AUTOSIZE );
    while(1) {
        frame = cvQueryFrame( capture );
        if( !frame ) break;
        cvShowImage( "video", frame );
        char c = cvWaitKey( 1000 / fps );
        if( c == 27 ) break;
    }
    cvReleaseCapture( &capture );
    cvDestroyWindow( "video" );
    return 0;
}

Writing your first OpenCV hello world program!

Download OpenCV 2.2 from SourceForge.
Download VisualC++ Express if you do not have an IDE

1. Create your new project for C++ , empty console application
2. Go to Tools > Option
3. Go to VC++ Directories
4. Add 2 new Include Directories (it's the path where you installed OpenCV, include folder):
- C:\OpenCV2.2\include
- C:\OpenCV2.2\include\opencv
5. Add 1 new Library Directory (it's the path where you installed OpenCV, lib folder):
- C:\OpenCV2.2\lib
6. Go to Linker in the left menu and select Input option
7. Add these entries on Additional Dependencies option:
"C:\OpenCV2.2\lib\opencv_core220d.lib"
"C:\OpenCV2.2\lib\opencv_highgui220d.lib"
"C:\OpenCV2.2\lib\opencv_video220d.lib" 
"C:\OpenCV2.2\lib\opencv_ml220d.lib"
"C:\OpenCV2.2\lib\opencv_legacy220d.lib"
"C:\OpenCV2.2\lib\opencv_imgproc220d.lib"

A sample hello world program :

#include "highgui.h"


int main ( int argc, char **argv )
{
  cvNamedWindow( "My Window", 1 );
  IplImage *img = cvCreateImage( cvSize( 640, 480 ), IPL_DEPTH_8U, 1 );
  CvFont font;
  double hScale = 1.0;
  double vScale = 1.0;
  int lineWidth = 1;
  cvInitFont( &font, CV_FONT_HERSHEY_SIMPLEX | CV_FONT_ITALIC,
              hScale, vScale, 0, lineWidth );
  cvPutText( img, "Hello World!", cvPoint( 200, 400 ), &font,
             cvScalar( 255, 255, 0 ) );
  cvShowImage( "My Window", img );
  cvWaitKey();
  return 0;
}

Run the program and you should see the above screen.


For OpenCV 2.3.1 
The steps are similar.
However the path varies depending on which build version you would want to use.
I am sticking with Win32 and VS2010


Some updates to the path:


5. Add 1 new Library Directory (it's the path where you installed OpenCV, lib folder):
- C:\OpenCV2.3\build\x86\vc10\lib

6. Go to Linker in the left menu and select Input option 

7. Add these entries on Additional Dependencies option

C:\OpenCV2.3\build\x86\vc10\lib\opencv_core231d.lib
C:\OpenCV2.3\build\x86\vc10\lib\opencv_highgui231d.lib
C:\OpenCV2.3\build\x86\vc10\lib\opencv_video231d.lib
C:\OpenCV2.3\build\x86\vc10\lib\opencv_ml231d.lib
C:\OpenCV2.3\build\x86\vc10\lib\opencv_legacy231d.lib
C:\OpenCV2.3\build\x86\vc10\lib\opencv_imgproc231d.lib