在iOS中的AVFoundation拍攝的圖像中保存CUSTOM元數據

Question

當我使用AVFoundation framework獲取圖像時，如何將自定義元數據保存在圖像中？

我知道我可以訪問屬性天氣它我有我的形象爲UIImage或CIImage但這些似乎有不同的屬性（即使它是相同的圖像）。

到目前爲止，我查閱字典是這樣的：（從含咖啡因的可可博客代碼取）

NSLog(@"about to request a capture from: %@", [self stillImageOutput]); 
    [[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) 
    { 

NSData *jpeg = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer] ; 

     CGImageSourceRef source = CGImageSourceCreateWithData((__bridge_retained CFDataRef)jpeg, NULL); 

     //get all the metadata in the image 
     NSDictionary *metadata = (__bridge NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source,0,NULL); 

     //make the metadata dictionary mutable so we can add properties to it 
     NSMutableDictionary *metadataAsMutable = [metadata mutableCopy]; 

     NSMutableDictionary *EXIFDictionary = [[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyExifDictionary]mutableCopy]; 
     NSMutableDictionary *GPSDictionary = [[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyGPSDictionary]mutableCopy]; 
     NSMutableDictionary *RAWDictionary = [[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyRawDictionary]mutableCopy]; 

     if(!EXIFDictionary) { 
      EXIFDictionary = [NSMutableDictionary dictionary]; 
     } 
     if(!GPSDictionary) { 
      GPSDictionary = [NSMutableDictionary dictionary]; 
     } 
     if(!RAWDictionary) { 
      RAWDictionary = [NSMutableDictionary dictionary]; 
     } 

     float _lat = gpsInfo.coordinate.latitude; 
     float _lon = gpsInfo.coordinate.longitude; 
     float _alt = gpsInfo.altitude; 
     NSDate *_date = gpsInfo.timestamp; 
     float _heading = gpsInfo.course;; 

     [GPSDictionary setValue:[NSNumber numberWithFloat:_lat] 
         forKey:(NSString*)kCGImagePropertyGPSLatitude]; 
     [GPSDictionary setValue:[NSNumber numberWithFloat:_lon] 
         forKey:(NSString*)kCGImagePropertyGPSLongitude]; 
     [GPSDictionary setValue:[NSNumber numberWithFloat:_alt] 
         forKey:(NSString*)kCGImagePropertyGPSAltitude]; 
     [GPSDictionary setValue:_date 
         forKey:(NSString*)kCGImagePropertyGPSDateStamp]; 
     [GPSDictionary setValue:[NSNumber numberWithFloat:_heading] 
         forKey:(NSString*)kCGImagePropertyGPSImgDirection]; 


     [EXIFDictionary setValue:@"Wasup" forKey:(NSString *)kCGImagePropertyExifUserComment]; 

     [RAWDictionary setValue:attitude forKey:@"Attitude"]; 

     //Add the modified Data back into the image’s metadata 
     [metadataAsMutable setObject:EXIFDictionary forKey:(NSString *)kCGImagePropertyExifDictionary]; 
     [metadataAsMutable setObject:GPSDictionary forKey:(NSString *)kCGImagePropertyGPSDictionary]; 
     [metadataAsMutable setObject:RAWDictionary forKey:(NSString *)kCGImagePropertyRawDictionary]; 

     NSLog(@"Info: %@",metadataAsMutable); 

     CFStringRef UTI = CGImageSourceGetType(source); //this is the type of image (e.g., public.jpeg) 

     //this will be the data CGImageDestinationRef will write into 
     NSMutableData *data = [NSMutableData data]; 

     CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)data,UTI,1,NULL); 

     if(!destination) { 
      NSLog(@"***Could not create image destination ***"); 
     } 

     //add the image contained in the image source to the destination, overidding the old metadata with our modified metadata 

     CGImageDestinationAddImageFromSource(destination,source,0, (__bridge CFDictionaryRef) metadataAsMutable); 

     //tell the destination to write the image data and metadata into our data object. 
     //It will return false if something goes wrong 
     BOOL success = NO; 
     success = CGImageDestinationFinalize(destination); 

     if(!success) { 
      NSLog(@"***Could not create data from image destination ***"); 
     } 

而且我可以節省我的形象是這樣的：

CIImage *testImage = [CIImage imageWithData:data]; 

     NSDictionary *propDict = [testImage properties]; 


     NSLog(@"Properties %@",propDict); 

或者這樣

UIImage *imageMod = [[UIImage alloc] initWithData:data]; 


CGImageSourceRef source2 = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL); 

     //get all the metadata in the image 
NSDictionary *metadata2 = (__bridge NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source2,0,NULL); 

NSLog(@"WASD: %@",metadata2); 

BUt都沒有選項返回我的自定義原始數據字典。

總之就是我想要做的是挽救我自己的對象由自己創造了一個場（在這種情況下cmattitude對象）

PD：當我與圖像合併之前NSLOG字典它確實有像我想要的所有文件。

Info: { 
    ColorModel = RGB; 
    DPIHeight = 72; 
    DPIWidth = 72; 
    Depth = 8; 
    Orientation = 6; 
    PixelHeight = 1080; 
    PixelWidth = 1920; 
    "{Exif}" =  { 
     ApertureValue = "2.526069"; 
     BrightnessValue = "4.013361"; 
     ColorSpace = 1; 
     ComponentsConfiguration =   (
      1, 
      2, 
      3, 
      0 
     ); 
     ExifVersion =   (
      2, 
      2, 
      1 
     ); 
     ExposureMode = 0; 
     ExposureProgram = 2; 
     ExposureTime = "0.03333334"; 
     FNumber = "2.4"; 
     Flash = 16; 
     FlashPixVersion =   (
      1, 
      0 
     ); 
     FocalLenIn35mmFilm = 35; 
     FocalLength = "4.28"; 
     ISOSpeedRatings =   (
      80 
     ); 
     MeteringMode = 5; 
     PixelXDimension = 1920; 
     PixelYDimension = 1080; 
     SceneCaptureType = 0; 
     SensingMethod = 2; 
     Sharpness = 0; 
     ShutterSpeedValue = "4.906905"; 
     SubjectArea =   (
      959, 
      539, 
      518, 
      388 
     ); 
     UserComment = "Wazup"; 
     WhiteBalance = 0; 
    }; 
    "{GPS}" =  { 
     Altitude = 102; 
     DateStamp = "2012-01-20 06:55:48 +0000"; 
     ImgDirection = "-1"; 
     Latitude = "35.02496"; 
     Longitude = "135.754"; 
    }; 
    "{Raw}" =  { 
     Attitude = "Pitch: 50.913760, Roll: 36.342350, Yaw: -164.272361 @ 0.048291\n"; 
    }; 
    "{TIFF}" =  { 
     Orientation = 6; 
     ResolutionUnit = 2; 
     XResolution = 72; 
     YResolution = 72; 
     "_YCbCrPositioning" = 1; 
    }; 

但是當我的新形象的NSLog字典它給了我這樣的CIIMage：

Properties { 
    ColorModel = RGB; 
    DPIHeight = 72; 
    DPIWidth = 72; 
    Depth = 8; 
    Orientation = 6; 
    PixelHeight = 1080; 
    PixelWidth = 1920; 
    "{Exif}" =  { 
     ApertureValue = "2.526069"; 
     BrightnessValue = "4.013361"; 
     ColorSpace = 1; 
     ComponentsConfiguration =   (
      0, 
      0, 
      0, 
      1 
     ); 
     ExifVersion =   (
      2, 
      2, 
      1 
     ); 
     ExposureMode = 0; 
     ExposureProgram = 2; 
     ExposureTime = "0.03333334"; 
     FNumber = "2.4"; 
     Flash = 16; 
     FlashPixVersion =   (
      1, 
      0 
     ); 
     FocalLenIn35mmFilm = 35; 
     FocalLength = "4.28"; 
     ISOSpeedRatings =   (
      80 
     ); 
     MeteringMode = 5; 
     PixelXDimension = 1920; 
     PixelYDimension = 1080; 
     SceneCaptureType = 0; 
     SensingMethod = 2; 
     Sharpness = 0; 
     ShutterSpeedValue = "4.906905"; 
     SubjectArea =   (
      959, 
      539, 
      518, 
      388 
     ); 
     UserComment = "Wazup"; 
     WhiteBalance = 0; 
    }; 
    "{GPS}" =  { 
     Altitude = 102; 
     ImgDirection = 0; 
     Latitude = "35.025"; 
     Longitude = "135.754"; 
    }; 
    "{JFIF}" =  { 
     DensityUnit = 1; 
     JFIFVersion =   (
      1, 
      1 
     ); 
     XDensity = 72; 
     YDensity = 72; 
    }; 
    "{TIFF}" =  { 
     Orientation = 6; 
     ResolutionUnit = 2; 
     XResolution = 72; 
     YResolution = 72; 
     "_YCbCrPositioning" = 1; 
    }; 

如果我NSLog的UIImage它給我更少的信息。

謝謝！

Answer 1

UIImage和CIImage不包含所有的元數據。實際上，將它從NSData轉換爲這兩種格式中的任意一種都會剝離大量元數據，因此，恕我直言，UIImage和應該僅在您計劃在UI中顯示或將其傳遞到CoreImage時使用。

你可以這樣寫的圖像屬性：

- (NSDictionary *)getImageProperties:(NSData *)imageData { 
    // get the original image metadata 
    CGImageSourceRef imageSourceRef = CGImageSourceCreateWithData((__bridge CFDataRef) imageData, NULL); 
    CFDictionaryRef properties = CGImageSourceCopyPropertiesAtIndex(imageSourceRef, 0, NULL); 
    NSDictionary *props = (__bridge_transfer NSDictionary *) properties; 
    CFRelease(imageSourceRef); 

    return props; 
} 

然後，您可以將您的NSDictionary爲NSMutableDictionary：

NSDictionary *props = [self getImageProperties:imageData]; 
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithDictionary:props]; 

之後，添加你想什麼領域。需要注意的是EXIF數據由kCGImagePropertyGPSDictionary抓住kCGImagePropertyExifDictionary，GPS數據發現，依此類推：

NSMutableDictionary *exifDictionary = properties[(__bridge NSString *) kCGImagePropertyExifDictionary]; 

看那CGImageProperties頭文件中所有可用的鑰匙。

好了，現在你已作出任何所需的更改需要元數據，其重新添加需要幾多個步驟：

// incoming image data 
NSData *imageData; 

// create the image ref 
CGDataProviderRef imgDataProvider = CGDataProviderCreateWithCFData((__bridge CFDataRef) imageData); 
CGImageRef imageRef = CGImageCreateWithJPEGDataProvider(imgDataProvider, NULL, true, kCGRenderingIntentDefault); 

// the updated properties from above 
NSMutableDictionary *mutableDictionary; 

// create the new output data 
CFMutableDataRef newImageData = CFDataCreateMutable(NULL, 0); 
// my code assumes JPEG type since the input is from the iOS device camera 
CFStringRef type = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, (__bridge CFStringRef) @"image/jpg", kUTTypeImage); 
// create the destination 
CGImageDestinationRef destination = CGImageDestinationCreateWithData(newImageData, type, 1, NULL); 
// add the image to the destination 
CGImageDestinationAddImage(destination, imageRef, (__bridge CFDictionaryRef) mutableDictionary); 
// finalize the write 
CGImageDestinationFinalize(destination); 

// memory cleanup 
CGDataProviderRelease(imgDataProvider); 
CGImageRelease(imageRef); 
CFRelease(type); 
CFRelease(destination); 

// your new image data 
NSData *newImage = (__bridge_transfer NSData *)newImageData; 

有你有它。