implementing sample buffer delegate method iphone

Question

Here is my code

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
   fromConnection:(AVCaptureConnection *)connection
{ 
    // Create a UIImage from the sample buffer data
    UIImage *image = [self imageFromSampleBuffer:sampleBuffer];
    dispatch_async(dispatch_get_main_queue(), ^{
      [[self imgView] setImage:image];
    });
}

Create a UIImage from sample buffer data

- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer 
{

     CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    // Lock the base address of the pixel buffer.
    CVPixelBufferLockBaseAddress(imageBuffer,0);

    // Get the number of bytes per row for the pixel buffer.
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
    // Get the pixel buffer width and height.
    size_t width = CVPixelBufferGetWidth(imageBuffer);
    size_t height = CVPixelBufferGetHeight(imageBuffer);

    // Create a device-dependent RGB color space.
    static CGColorSpaceRef colorSpace = NULL;
    if (colorSpace == NULL) {
        colorSpace = CGColorSpaceCreateDeviceRGB();
    if (colorSpace == NULL) {
           // Handle the error appropriately.
           return nil;
        }
    }

    // Get the base address of the pixel buffer.
    uint8_t *baseAddress = malloc( bytesPerRow * height );    
    memcpy( baseAddress, CVPixelBufferGetBaseAddress(imageBuffer), bytesPerRow * height );

    // Get the data size for contiguous planes of the pixel buffer.
    size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);

    // Create a Quartz direct-access data provider that uses data we supply.
    CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize, NULL);
    // Create a bitmap image from data supplied by the data provider.
    CGImageRef cgImage = CGImageCreate(width, height, 8, 32, bytesPerRow,
              colorSpace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little, dataProvider, NULL, true, kCGRenderingIntentDefault);

    CGDataProviderRelease(dataProvider);

    // Create and return an image object to represent the Quartz image.
    UIImage *image = [UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);
    free(baseAddress);
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);

    return image;
}

Still i am getting no image in my image view can anyone help me find mistake.

Thanks in advance.

Answer 1

This is the code that made my work:

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
   fromConnection:(AVCaptureConnection *)connection
{ 
// Create a UIImage from the sample buffer data
UIImage *img = [self imageFromSampleBuffer:sampleBuffer];
dispatch_async(dispatch_get_main_queue(), ^{

    self.imgView.image=img;
});

}
// Create a UIImage from sample buffer data
- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer 
{

// Get a CMSampleBuffer's Core Video image buffer for the media data
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer, 0); 

// Get the number of bytes per row for the pixel buffer
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
// Get the pixel buffer width and height
size_t width = CVPixelBufferGetWidth(imageBuffer); 
size_t height = CVPixelBufferGetHeight(imageBuffer); 


// Get the number of bytes per row for the pixel buffer
u_int8_t *baseAddress = (u_int8_t *)malloc(bytesPerRow*height);
memcpy( baseAddress, CVPixelBufferGetBaseAddress(imageBuffer), bytesPerRow * height     );

// size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);

// Create a device-dependent RGB color space
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

// Create a bitmap graphics context with the sample buffer data

//The context draws into a bitmap which is `width'
//  pixels wide and `height' pixels high. The number of components for each
//      pixel is specified by `space'
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, 
                                             bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst); 

// Create a Quartz image from the pixel data in the bitmap graphics context
CGImageRef quartzImage = CGBitmapContextCreateImage(context);

// Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer,0);


// Free up the context and color space
CGContextRelease(context); 
CGColorSpaceRelease(colorSpace);

// Create an image object from the Quartz image
UIImage *image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationRight];

free(baseAddress);
// Release the Quartz image
CGImageRelease(quartzImage);


return (image);
}