title: OpenCV and iPhone
body: <p>I am writing an application to create a movie file from a bunch of images on an iPhone. I am using OpenCv. I downloaded OpenCv static libraries for ARM(iPhone's native instruction architecture) and the libraries were generated just fine. There were no problems linking to them libraries.</p>
  
  <p>As a first step, I was trying to create a .avi file using one image, to see if it works. But <code>cvCreateVideoWriter</code> always returns me a NULL value. I did some searching and I believe its due to the codec not being present. I am trying this on the iPhone simulator.  This is what i do:</p>
  
  <pre><code>- (void)viewDidLoad {
   [super viewDidLoad];
   UIImage *anImage = [UIImage imageNamed:@"1.jpg"];
   IplImage *img_color = [self CreateIplImageFromUIImage:anImage];
   //The image gets created just fine
  
   CvVideoWriter *writer = 
     cvCreateVideoWriter("out.avi",CV_FOURCC('P','I','M','1'),
                         25,cvSize(320,480),1);
   //writer is always null
  
   int result = cvWriteFrame(writer, img_color);
   NSLog(@"\n%d",result);
   //hence this is also 0 all the time
   cvReleaseVideoWriter(&amp;writer);
  }
  </code></pre>
  
  <p>I am not sure about the second parameter. What sort of codec or what exactly does it do...
  I am a n00B at this. Any suggestions?</p>