|Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact|
|Full name||HD Photo, Version 1.0 (formerly Windows Media Photo)|
Format for continuous-tone still images that supports a wide range of features including:
The developer states that the format delivers "a lightweight, high-performance algorithm with a small memory footprint that enables practical, in-device encoding and decoding."
Support for HD Photo is provided by the Windows Imaging Component (WIC) installable codec architecture and the Windows Presentation Foundation (WPF; concerned in part with user interfaces) developed for the Windows Vista operating system. Microsoft states that Vista represents the integration of imaging at the operating system level, reducing the level of activity required of specific applications.
In a July 31, 2007, press release, Microsoft Corp. announced the decision by the Joint Photographic Expert Group (JPEG) to introduce a new work item for the standardization of HD Photo which, if approved, would lead to a format tentatively titled "JPEG XR."
|Production phase||Used for content in middle and final states. If adopted by camera manufacturers, then initial-state use would also occur.|
|LC experience or existing holdings||None.|
|Disclosure||Developed by the Microsoft Corporation.|
|Documentation||The container format and API are specified in the HD Photo Feature Specification (2006); in February 2012, available from http://msdn.microsoft.com/en-us/windows/hardware/gg463400.aspx. Information about the HD Photo compressed bitstream format and how to implement an encoder and decoder are part of the HD Photo Device Porting Kit 1.0 (DPK) provides; in February 2012, available from http://msdn.microsoft.com/en-us/windows/hardware/gg463381.aspx.|
|Adoption||Introduced in 2006, with some dependency on the level of adoption of the new Windows Vista operating/application system, available in 2007. In December 2007, Microsoft announced the availability of plug-ins for Adobe PhotoShop. The compiler of this page has not encountered indications of significant adoption of WMP_1_0 as of early 2008; Comments welcome.|
|Licensing and patents||
Licensing applies to applications that create or display images, not to the images themselves. A Microsoft Web page consulted in August 2006 and no longer available in January 2007 (http://www.microsoft.com/windows/windowsmedia/licensing/wmphoto.aspx) stated, "Under most conditions, Windows Media Photo technology is available free of charge; royalties are associated only with specific licensing conditions."
According to the Wikipedia article "HD Photo" (consulted February 6, 2008), "A Microsoft representative stated in a January 2007 interview that in order to encourage the adoption and use of HD Photo, the specification is made available under the Microsoft Open Specification Promise, which asserts that Microsoft offers the specification for free, and will not file suit on the patented technology, and that open-source software can therefore make use of the format. However, as of Microsoft's December 4, 2007 update, HD Photo is still not among the technologies that Microsoft has listed as being covered by the Open Specification Promise."
|Transparency||Depends upon algorithms and tools to read; will require sophistication to build tools.|
WMP_1_0 uses a "TIFF-like" file container to store image data in a table of Image File Directory (IFD) tags, using tag numbers from TIFF's baseline, extended, and "private" sets. Examples of tags drawn from extended and private TIFF sets: ICCProfile (34675), XMPMetadata (700), and EXIFMetadata (34665). For an overview of tags, including a listing of WMP_1_0 tags, see Tags for TIFF and Related Specifications.
The large number of possible image encodings are identified by means of GUIDs specified by Microsoft. (This contrasts with an approach based upon the placement of data in a set of tags for such features as bits per pixel, photometric interpretation, and so on.)
|Technical protection considerations||No DRM technology; see Notes below.|
|Clarity (high image resolution)||Very high levels of image quality are supported. The Wikipedia article "HD Photo" (as of February 6, 2008) reports, "HD Photo is an image codec that gives a high-dynamic-range image encoding while requiring only integer operations (with no divides) for both compression and decompression. It supports monochrome, RGB, CMYK and even n-channel color representation, using up to 16-bit unsigned integer representation, or up to 32-bit fixed point or floating point representation, and also supports RGBE (Radiance). . . . All color representations are transformed to an internal color representation. The transformation is entirely reversible, so, by using appropriate quantizers, both lossy and lossless compression can be achieved."|
|Color maintenance||Excellent support; files can include ICC profiles; extended color gamuts are supported.|
|Support for vector graphics, including graphic effects and typography||Not investigated|
|Functionality beyond normal rendering||Paraphrasing The Wikipedia article "HD Photo" (as of February 6, 2008): An alpha channel may be present for transparency. The format allows decoding part of an image, without decoding the entire image. Full decoding is also unnecessary for certain operations such as cropping, downsampling, horizontal or vertical flips, or cardinal rotations.|
|From the Wikipedia article "HD Photo" (as of February 6, 2008). The extension "wdp" is labeled "formerly."|
|Internet Media Type||image/vnd.ms-photo
||From the Wikipedia article "HD Photo" (as of February 6, 2008)|
|Magic numbers||Hex: 49 49 BC
|From the The File Extension Source|
Regarding compression: The Wikipedia article "HD Photo" offers a good overview of the format. The following summation is from the January 2007 version of this article; a more detailed version was available in February 2008. The 2007 summation stated that HD Photo "uses a reversible color space conversion, a reversible lapped biorthogonal transform and a non-arithmetic entropy encoding scheme, which is very efficient in preserving high frequency image data. This makes the algorithm retain a higher image quality at high compression ratios. The transform operation needs 3 multiply and add operations and 7 add or shift operations at the highest quality level and in the highest performance mode, 1 multiply and add operation and 4 add or shifts are required per pixel, giving the codec a high performance. [HD Photo] processes images in 16x16 macroblocks."
Regarding digital rights management: In a blog consulted in August 2006, HD Photo Program Manager Bill Crow commented:
Other notes: Bill Crow's own blog is informative; here are some excerpts collected in August 2006: