AVCaptureStillImageOutput缺少元数据

Question

我使用以下代码捕获图像：

[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) {
     CFDictionaryRef exifAttachments = CMGetAttachment(imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
     NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
     UIImage *image = [[UIImage alloc] initWithData:imageData];
     NSDictionary *metadata = (__bridge NSDictionary*)exifAttachments;
     NSLog(@"%@",metadata");
}];

这是记录的输出：

ApertureValue = "2.526068811667588";
BrightnessValue = "-0.5270684580355165";
ExposureMode = 0;
ExposureProgram = 2;
ExposureTime = "0.06666666666666667";
FNumber = "2.4";
Flash = 16;
FocalLenIn35mmFilm = 35;
FocalLength = "4.28";
ISOSpeedRatings =     (
    500
);
MeteringMode = 5;
PixelXDimension = 3264;
PixelYDimension = 2448;
SceneType = 1;
SensingMethod = 2;
ShutterSpeedValue = "3.906905022631062";
SubjectArea =     (
    1631,
    1223,
    881,
    881
);
WhiteBalance = 0;

为什么我没有得到任何时间相关的元数据？我想知道拍摄图像的时间。

Answer 1

我确定将日期和时间添加到相机胶卷后添加到元数据中（开发人员部分没有任何工作）。无需担心信息丢失！