How to access photo EXIF in pictures taken from camera in iOS 4.0+?

Question

How do I access the EXIF info in a picture from the camera taken using the new 4.0/4.1 APIs?

I use captureStillImageAsynchronouslyFromConnection to take the picture and:

[AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];

to get the jpg data but how do I extract the EXIF?

The doco makes references to imageDataSampleBuffer containing EXIF (I can see it in there if I examine the variable in the console):

"The buffer attachments may contain metadata appropriate to the image data format. For example, a buffer containing JPEG data may carry a kCGImagePropertyExifDictionary as an attachment"

But I can't figure out how to manipulate a CMSampleBufferRef to acces it.

Thanks.

Answer 1

This library could be of assistance.

Answer 2

The Image I/O Framework which was introduced in iOS4 allows one to read EXIF properties from a picture according to the documentation.

Link: CGImageSource Reference - have a look at the CGImageSourceCopyPropertiesAtIndex function.