Ios – Having trouble creating UIImage from CIImage in iOS5

You need AVAssetWriterInputPixelBufferAdaptor, here is the code to create it :

    // Create dictionary for pixel buffer adaptor
NSDictionary *bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA], kCVPixelBufferPixelFormatTypeKey, nil];

// Create pixel buffer adaptor
m_pixelsBufferAdaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] initWithAssetWriterInput:assetWriterInput sourcePixelBufferAttributes:bufferAttributes];

And the code to use it :

// If ready to have more media data
if (m_pixelsBufferAdaptor.assetWriterInput.readyForMoreMediaData) {
    // Create a pixel buffer
    CVPixelBufferRef pixelsBuffer = NULL;
    CVPixelBufferPoolCreatePixelBuffer(NULL, m_pixelsBufferAdaptor.pixelBufferPool, &pixelsBuffer);

    // Lock pixel buffer address
    CVPixelBufferLockBaseAddress(pixelsBuffer, 0);

    // Create your function to set your pixels data in the buffer (in your case, fill with your finalImage data)
    [self yourFunctionToPutDataInPixelBuffer:CVPixelBufferGetBaseAddress(pixelsBuffer)];

    // Unlock pixel buffer address
    CVPixelBufferUnlockBaseAddress(pixelsBuffer, 0);

    // Append pixel buffer (calculate currentFrameTime with your needing, the most simplest way is to have a frame time starting at 0 and increment each time you write a frame with the time of a frame (inverse of your framerate))
    [m_pixelsBufferAdaptor appendPixelBuffer:pixelsBuffer withPresentationTime:currentFrameTime];

    // Release pixel buffer
    CVPixelBufferRelease(pixelsBuffer);
}

And don't forget to release your pixelsBufferAdaptor.

After a lot of trial and error, I worked out how to do this.

Hint: Apple's official docs are - simply - wrong. The code they give you doesn't actually work.

I wrote it up here with step-by-step instructions:

http://red-glasses.com/index.php/tutorials/ios4-take-photos-with-live-video-preview-using-avfoundation/

Lots of code on the link, but in summary:

-(void) viewDidAppear:(BOOL)animated
{
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    session.sessionPreset = AVCaptureSessionPresetMedium;

    CALayer *viewLayer = self.vImagePreview.layer;
    NSLog(@"viewLayer = %@", viewLayer);

    AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

    captureVideoPreviewLayer.frame = self.vImagePreview.bounds;
    [self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (!input) {
        // Handle the error appropriately.
        NSLog(@"ERROR: trying to open camera: %@", error);
    }
    [session addInput:input];

stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];

[session addOutput:stillImageOutput];

    [session startRunning];
}

-(IBAction) captureNow
{
    AVCaptureConnection *videoConnection = nil;
    for (AVCaptureConnection *connection in stillImageOutput.connections)
    {
        for (AVCaptureInputPort *port in [connection inputPorts])
        {
            if ([[port mediaType] isEqual:AVMediaTypeVideo] )
            {
                videoConnection = connection;
                break;
            }
        }
        if (videoConnection) { break; }
    }

    NSLog(@"about to request a capture from: %@", stillImageOutput);
    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
    {
         CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
         if (exifAttachments)
         {
            // Do something with the attachments.
            NSLog(@"attachements: %@", exifAttachments);
         }
        else
            NSLog(@"no attachments");

        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
        UIImage *image = [[UIImage alloc] initWithData:imageData];

        self.vImage.image = image;
     }];
}