ImageGear .NET v25.2 - Updated
HD Photo
Developer Guide > File Formats and Compressions > File Formats > File Formats Reference > HD Photo
Full Name HD Photo (Windows Media Photo)
Format ID ImGearFormats.HDPHOTO
File Extension(s) *.wdp
Data Type Raster Image
Data Encoding Binary
Multi-Page Support No
Alpha Channel Support Yes
Metadata Update Support No
ImageGear Platforms Support Win32 (DLL only), Win64, .NET, .NET64

ImageGear Supported Versions

ImageGear Supported Features

ImageGear Read Support

ImageGear Write Support

ImageGear Filter Control Parameters

Filter Control Parameter Type Default Value Available Values Description
Lossless Boolean False False,

True
Set to True to use lossless compression during save.
ImageQuality Single 0.9 0 to 1.0 Image quality level. 1.0 represents lossless compression.
UseAdvancedParameters Boolean False False, True When true, QualityLevel, OverlapLevel, and SubsamplingLevel are used in place of the ImageQualityLevel. When false, QualityLevel, OverlapLevel, and SubsamplingLevel are set based on ImageQualityLevel
Advanced.Quality Byte 1 0..255 Controls quantization of the main image. A value of 1 sets lossless mode (no quantization). Increasing values result in greater quantization and thus greater compression ratios and lower image quality. This parameter is tightly related with Advanced.Subsampling and Advanced.Overlap parameters, and its behavior may differ depending on source image content. If the application needs a single parameter to control image quality, the use of the basic ImageQuality parameter is recommended.
Advanced.Overlap Byte 1 0,1,2 0 - No overlap processing is enabled;

1 - One level of overlap processing is enabled. Encoded values of 4x4 blocks are modified based on the values of neighboring blocks;

2 - Two levels of overlap processing are enabled. In addition to the first level of processing, encoded values of 16x16 macro blocks are modified based on the values of neighboring macro blocks.
Advanced.Subsampling Byte 3 0, 1, 2, 3 0 - 4:0:0 encoding. Chroma content is discarded, luminance is preserved.

1 - 4:2:0 encoding. Chroma resolution is reduced by 1/4 of luminance resolution.

2 - 4:2:2 encoding. Chroma resolution is reduced to 1/2 of luminance resolution.

3 - 4:4:4 encoding. Chroma resolution is preserved.
Advanced.HorizontalTileSlices Short 0 0..4095 The number of horizontal divisions to use during compression encoding.
Advanced.VerticalTileSlices Short 0 0..4095 The number of vertical divisions to use during compression encoding.
Advanced.FrequencyOrder Boolean True False,

True
True to encode the image in frequency order; False to encode the image by its spatial orientation.
Advanced.InterleavedAlpha Boolean False False,

True
True if the image is to be encoded with an additional interleaved alpha channel; False if planar alpha channel is to be used.
Advanced.AlphaQuality Byte 1 0..255 The compression quality for a planar alpha channel image. A value of 1 is considered lossless.
Advanced.CompressedDomainTranscode Boolean True False,

True
True if compressed domain operations can be used.
Advanced.ImageDataDiscard Byte 1 0, 1, 2, 3 0 - No image frequency data is discarded.

1 - FlexBits are discarded. The image quality of the image is reduced without changing the effective resolution of the image.

2 - HighPass frequency data band is discarded. The image's effective resolution is reduced by a factor of 4 in both dimensions.

3 - HighPass and LowPass frequency data bands are discarded. The image's effective resolution is reduced by a factor of 16 in both dimensions
Advanced.AlphaDataDiscard Byte 1 0..4 0 - No image frequency data is discarded.

1 - FlexBits are discarded. The image quality of the image is reduced without changing the effective resolution of the image.

2 - HighPass frequency data band is discarded. The image's effective resolution is reduced by a factor of 4 in both dimensions.

3 - HighPass and LowPass frequency data bands are discarded. The image's effective resolution is reduced by a factor of 16 in both dimensions.

4 - The alpha channel is completely discarded. The pixel format is changed to reflect the removal of the alpha channel.
Advanced.IgnoreOverlap Boolean False False,

True
True if overlap is ignored. This value is only valid when CompressedDomainTranscode is true and a sub-region encode is requested.

Non-Image Data Structure

HD Photo file format has different non-image data that can be stored before and after an image data. The HD Photo metadata design allows reading and writing the following non-image data (exactly like in System.Windows.Media.Imaging.BitmapMetadata; strings by default):

Tag Name ID Description
ApplicationName ImGearHDPhotoTagIDs.APPLICATION_NAME Gets or sets a value that identifies the name of the application that was used to construct or alter an image file.
Author (collection of strings) ImGearHDPhotoTagIDs.AUTHORS Single author is ImGearHDPhotoTagIDs.AUTHOR Gets or sets a value that represents the author of an image.
CameraManufacturer ImGearHDPhotoTagIDs.CAMERA_MANUFACTURER Gets or sets a value that identifies the camera manufacturer that is associated with an image.
CameraModel ImGearHDPhotoTagIDs.CAMERA_MODEL Gets or sets a value that identifies the camera model that was used to capture the image.
Comment ImGearHDPhotoTagIDs.COMMENT Gets or sets a value that represents a comment that is associated with the image file.
Copyright ImGearHDPhotoTagIDs.COPYRIGHT Gets or sets a value that indicates copyright information that is associated with the image file.
DateTaken ImGearHDPhotoTagIDs.DATE_TAKEN Gets or sets a value that indicates the date that the image was taken.
Keywords (collection of strings ) ImGearHDPhotoTagIDs.KEYWORDS

Single keyword is ImGearHDPhotoTagIDs.KEYWORD
Gets or sets a collection of keywords that describe the bitmap image.
Rating (integer 0 to 5) ImGearHDPhotoTagIDs.RATING Gets or sets a value that identifies the image rating.
Subject ImGearHDPhotoTagIDs.SUBJECT Gets or sets a value that indicates the subject matter of the bitmap image.
Title ImGearHDPhotoTagIDs.TITLE Gets or sets a value that identifies the title of an image file.

 

Comments

HD Photo, also known as Windows Media Photo (WMPhoto), is a new file format for continuous-tone still images, developed by Microsoft as a part of the Windows Media family that surpasses the limitations of existing image formats. HD Photo supports a wide range of features, including:

HD Photo delivers a lightweight, high performance algorithm with a small memory footprint that enables practical, in-device encoding and decoding. HD Photo delivers image quality that is comparable to JPEG-2000 and more than twice the quality of JPEG.

 

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