ImageGear for C and C++ on Linux v18.8 - Updated
DCRAW Metadata Structure
User Guide > File Formats and Compressions > File Formats > Metadata Structures > DCRAW Metadata Structure

Brief information on DCRAW metadata levels is provided in the set of tables below:

DCRAW Level

Name Id Type Value Type Value Value Length Read Only
"Common" IGMDTAG_ID_DCRAW_COMMON LEVEL_START 0 NULL 0 TRUE
"EXIF" IG_FORMAT_EXIF_TIFF LEVEL_START 0 NULL 0 TRUE
"TIFF" IG_FORMAT_TIF LEVEL_START 0 NULL 0 TRUE
"CIFF" IG_FORMAT_CIFF LEVEL_START 0 NULL 0 TRUE
"Statistics" IGMDTAG_ID_DCRAW_STATISTICS LEVEL_START 0 NULL 0 TRUE

Common and Statistic levels are available for specific Camera Raw images only. Please see ImageGear Supported Digital Camera RAW Formats for a list of Camera Raw formats supported by ImageGear, which includes the availability of the metadata sections.

Common Level

The Common sub-tree contains values that are common or useful for all raw files.

All values in the Common sub-tree have Type = VALUE_ITEM and are Read Only.

Name Id Description
AsShotNeutral IGMDTAG_ID_DCRAW_ASSHOTNEUTRAL Specifies the selected white balance at time of capture, encoded as the coordinates of a perfectly neutral color in linear reference space values.
BaselineExposure IGMDTAG_ID_DCRAW_BASELINEEXPOSURE Specifies baseline exposure of the camera, in EV units. Application may use this value to adjust exposure compensation for particular camera model.
BitsPerSample IGMDTAG_ID_DCRAW_BITSPERSAMPLE Bits per sample in the original raw image (before reconstruction)
BlackLevelRepeatDim IGMDTAG_ID_DCRAW_BLACKLEVELREPEATDIM This tag specifies repeat pattern size for the "BlackLevel" tag.
CalibrationIlluminant1 IGMDTAG_ID_DCRAW_CALIBRATIONILLUMINANT1 The illuminant used for ColorMatrix1 color conversion matrix. Allowed values are the same as allowed values for LightSource EXIF tag (see Exif specification).
CalibrationIlluminant2 IGMDTAG_ID_DCRAW_CALIBRATIONILLUMINANT1 The illuminant used for ColorMatrix2 color conversion matrix. Allowed values are the same as allowed values for LightSource EXIF tag (see Exif specification).
CFAPattern IGMDTAG_ID_DCRAW_CFAPATTERN This tag encodes the actual color filter array geometric pattern of the image sensor used to capture the single sensor color image.
CFARepeatPatternDim IGMDTAG_ID_DCRAW_CFAREPEATPATTERNDIM This tag encodes the number of pixels horizontally and vertically that are needed to uniquely define the repeat pattern of the color filter array.
ColorMatrix1 IGMDTAG_ID_DCRAW_COLORMATRIX1 Conversion matrix from XYZ to camera color space, for illuminant specified by CalibrationIlluminant1 tag. Matrix is stored in row scan order.
ColorMatrix2 IGMDTAG_ID_DCRAW_COLORMATRIX2 Conversion matrix from XYZ to camera color space, for illuminant specified by CalibrationIlluminant2 tag. Matrix is stored in row scan order.
ColorPlanes IGMDTAG_ID_DCRAW_COLORPLANES Number of colors in the CFA pattern
ImageHeight IGMDTAG_ID_DCRAW_IMAGEHEIGHT Image height after that masked pixels were trimmed out
ImageWidth IGMDTAG_ID_DCRAW_IMAGEWIDTH Image width after that masked pixels were trimmed out
Make IGMDTAG_ID_DCRAW_MAKE Name of the camera manufacturer
Model IGMDTAG_ID_DCRAW_MODEL Name of the camera model
PhotometricInterpretation IGMDTAG_ID_DCRAW_PHOTOMETRICINTERPRETATION TIF_PHOTO_CFA, TIF_PHOTO_RGB
RawHeight IGMDTAG_ID_DCRAW_RAWHEIGHT Raw Image Height, including masked pixels
RawLeft IGMDTAG_ID_DCRAW_RAWLEFT X coordinate of first column of non-masked pixels
RawTop IGMDTAG_ID_DCRAW_RAWTOP Y coordinate of first row of non-masked pixels
RawWidth IGMDTAG_ID_DCRAW_RAWWIDTH Raw Image Width, including masked pixels
SamplesPerPixel IGMDTAG_ID_DCRAW_SAMPLESPERPIXEL Number of samples per pixel in the original image, before reconstruction
TimeStamp IGMDTAG_ID_DCRAW_TIMESTAMP Time stamp
UniqueCameraModel IGMDTAG_ID_DCRAW_UNIQUECAMERAMODEL Unique, non-localized name for the camera model that created the image in the raw file.
WhiteLevel IGMDTAG_ID_DCRAW_WHITELEVEL Image pixel value that corresponds to fully saturated encoding Level.

Format-Specific Level

This Level includes format-specific metadata that is found in the image (EXIF, TIFF or CIFF). See corresponding sections for structure of metadata for these formats.

Statistics

This section contains data which is collected during image loading, rather than obtained from image's header or metadata. Only image loading functions, such as IG_fltr_load_file, generate this section. Header reading functions, such as IG_info_get, do not generate it.

For some cameras ImageGear uses predefined values for BlackLevel, so they are not calculated from pixel data. In this case, ImageGear also places BlackLevel tag to Statistics section, rather than in Common section, for uniformity reasons.

The following tags can be present in the Statistics section:

Name Id Description
BlackLevelRepeatDim IGMDTAG_ID_DCRAW_BLACKLEVELREPEATDIM This tag specifies repeat pattern size for the "BlackLevel" tag.
BlackLevel IGMDTAG_ID_DCRAW_BLACKLEVEL This tag specifies the zero light (a.k.a. thermal black or black current) encoding Level. It is calculated during image loading by averaging pixel values in the masked areas of the image.