Saturday, 1 August 2009

JPEG XR is Now an International Standard

I’m very excited to share the news that JPEG XR is now an approved ISO/IEC International standard.  (It’s official designation is ISO/IEC 29199-2.)  In addition, JPEG XR has also been approved as ITU Recommendation T.832.  You can find more information in the press release from the JPEG Committee.

As I’ve discussed in previous blog posts here, JPEG XR is the standardized incarnation of HD Photo, an innovative new format for digital photos developed at Microsoft, and first shipped in  Windows Vista.  There are a few minor differences between HD Photo and JPEG XR; these changes were the result of some excellent work by the JPEG Committee that helped insure the highest possible quality for the approved standard.

JPEG XR offers some dramatic benefits when compared to the original JPEG file format that we all know and love:

  • Better compression – JPEG XR offers improved efficiency compared to JPEG, and the type of compression artifacts are often less objectionable than the typical JPEG compression artifacts.  JPEG XR offers a very wide range of compression levels, including perceptively lossless or mathematically lossless compression.  Regardless of your requirements, JPEG XR probably offers a compression option that’s ideal for that scenario.
  • More image formats – JPEG XR supports 8bpc (bits per channel), 16bpc and 32bpc, as well as several special bit depth formats.  Pixel values can be stored as either integers, scaled fixed point numbers or full floating point values; this provides full support for numerous high dynamic range (HDR) imaging scenarios, as well as support for wide gamut color spaces.  In addition to 3-channel RGB, JPEG XR supports monochrome, CMYK and n-channel formats up to 16 independent channels.  many of these formats also support an alpha channel.   This wide range of image formats allows for dramatically better image quality and allows this single new file format to effectively replace many previous formats that were required for specific scenarios.
  • Advanced decoding features – JPEG XR provides progressive decoding, allowing lower resolution previews or specific cropped areas to be displayed without the need to decode the entire image.  Additionally, JPEG XR images can be cropped, rotated, flipped and resized (within certain constraints) without ever needing to decode and then re-encode the image.  That means these operations are much, much faster and no additional image quality is lost due to the additional encoding steps.

The many innovations delivered in JPEG XR originated from over ten years of research and development at Microsoft.  And through our participation as a member of the JPEG Committee, we’ve been able to deliver additional improvements and create an International standard available to everyone.

So the next question everyone asks is “when will it be available in a camera?”  Since I don’t work for a camera company, I can’t answer that question.  But I’m pleased and proud that because JPEG XR is now a free International standard, there’s very little standing in the way of making that happen!

Via Bill Crow's Digital Imaging & Photography blog

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