iphone - 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

iOS4 中引入的 Image I/O Framework 允许人们根据文档从图片中读取 EXIF 属性。

链接：CGImageSource 参考- 看看CGImageSourceCopyPropertiesAtIndex函数。

Answer 2

这个图书馆可以提供帮助。

Answer 3

您必须将图像实际保存到照片库中，以便将 EXIF 数据添加到图像中。之后，您可以使用 ALAssetLibrary 来检索图像以及 EXIF 信息。