With the public release of its new Vista operating system on Tuesday, Microsoft will also launch a new image file format, known as HD Photo.

January 28, 2007: With the public release of its new Vista operating system on Tuesday, Microsoft will also launch a new image file format, known as HD Photo.

Formerly referred to as Windows Media Photo, HD Photo is a new file format for continuous-tone still images that claims to surpass the limitations of existing image formats, such as JPEG. According to Microsoft’s website (http://www.microsoft.com/windows/windowsmedia/forpros/wmphoto/), “HD Photo delivers a lightweight, high performance algorithm with a small memory footprint that enables practical, in-device encoding and decoding. It delivers compression quality comparable with JPEG-2000 and more than twice the quality of JPEG.”

HD Photo supports a wide range of features including:
– lossless or high-quality lossy compression (files are half the size of JPEG files – but with the same quality);
– the HD Photo algorithm uses simple instructions that are easily built into image processing chips;
– the format uses the Microsoft scRGB colour space, which has a wider gamut than sRGB;
– multiple colour formats are supported for display or print;
– images are stored with at least 16 bits per pixel (JPEG only stores 8 bits);
– fixed or floating point high-dynamic-range image encoding with 32-bit/colour support;
– actual images can be huge – up to 262 million pixels on an edge – as long as the compressed file is smaller than 32GB;
– efficient decoding for multiple resolutions and sub-regions to improve performance and reduce memory requirements;
– minimal overhead for format conversion or transformations during decode.

Detailed information about the file container format plus a device porting kit can be found on the above-mentioned web page. Adobe has already agreed to support HD photo and is working with Microsoft on a plug-in to allow both Windows and Mac OS X Photoshop users to open and save HD Photo files.