Benefits of JPEG XR

Benefits of JPEG XR

If you happened to read my last few posts, you will have noticed that I was proposing the benefits of F#. Before I finish that set of posts, I would like to take a diversion and briefly mention a highly underutilized feature that greatly interests me. That item of interest is JPEG XR (1).

The primary benefits that I see for JPEG XR are:

  1. better compression than traditional JPEG
  2. option for lossless compression
  3. JPEG XR is an ISO Standard (2)(3)
  4. support for more colors than JPEG and JPEG 2000
  5. transparency
  6. the ability to embed tags in your images

Improved Lossy Compression

Of these benefits, Item#1 is probably the most significant advantage so I will discuss it first. While the results tend to vary depending upon the application, JPEG XR seems to give me better compression than traditional JPEG. In fact, Microsoft states "The JPEG XR format can achieve up to twice the compression efficiency of the original JPEG format, with less noticeable compression artifacts. " (4) To me, the better compression of JPEG XR seems to be more obvious at the rougher image quality levels.

Recently, I tried to make the background image for this site. Because the image had to be loaded on the first visit to this site, the image had to be small in size. Also, because the image had to occupy most of the screen, it had to have relatively large pixel dimensions. To achieve both of these goals, I eventually used JPEG XR instead of JPEG. The JPEG XR format seemed to allow the background image to render to the user *much* quicker on lower bandwidth levels than the JPEG format did. While I would like to show you a side by side comparison of my background image with JPEG and JPEG XR compressions, doing so would take up too much of my limited bandwidth. Instead, I will show you a much simpler example.

While this is something of a contrived example, it does demonstrate my point. To show an example of how JPEG XR *might* outperform traditional JPEG compression, I used a picture I took of a chair on top of carpet. I then experimented with various JPEG XR and traditional JPEG quality settings in Paint.NET. At the lower quality settings, traditional JPEG seemed to be more easily confused by the carpet background while JPEG XR seemed to do well. Also, at lower quality settings some of the colors chosen by traditional JPEG seemed to be a bit odd. To get an objective result however, I decided to find the lowest JPEG XR quality setting that I could tolerate and then save that image along with a the same traditional JPEG image at the same file size and this picture represents the result:

Picture showing better performance of JPEG XR compared to 
    similar traditional JPEG image
Figure 1
(PNG Image showing JPEG XR and traditional JPEG compression side by side)

This could be a matter of taste, but you *may* be able to see in Figure#1 how the chair in the JPEG XR image has slightly smoother curves and less pixilation. Also, you might think that the text copyright text shows up clearer in the JPEG XR image than it does in the traditional JPEG image of the same size. Admittedly, this is a bit of a contrived example, but I had to use smaller and less realistic images to stay within a reasonable bandwidth. If you are so inclined, you can download the JPEG XR Plugin for Paint.NET and try a similar experiment with much larger files.

New Lossless Compression

The next most significant option for JPEG XR is its option for lossless compression. This lossless compression allows JPEG XR to compete with lossless PNG and in some cases maybe even RAW image formats. In the case of lossless compression, the same chair image appeared to take 223 KB to store in 24 bit PNG format but only 125 KB to store in 24 bit lossless JPEG XR. So JPEG XR *seems* to me to offer better compression than PNG. In fact, some people have proposed that some high end “hobbyist” cameras do away with RAW and use JPEG XR instead.

While Ms. Lori Grunin didn’t actually say we should do away with RAW, I did understand her to imply that JPEG XR has some potential in the professional photography area. In a 2008 post, I understood Ms. Grunin to say “Raw files--data straight from the sensor--place a heavy performance burden on a digital camera. Though they're same dimensions as JPEGs, raw files support 12-bit or deeper color, while JPEG and its widely ignored successor, JPEG 2000, support only 8 bits. That makes the raw file footprint bigger, even when compressed, and increases the required amount of buffer memory.” (5) There are a few things to gleam from that statement, one is that in 2008, the color depth of JPEG 2000 was apparently not much better than original three channel 24 bit model of classic JPEGs. Another thing is that RAW apparently just takes up too much memory. Personally, I’ve never had the money to buy a professional camera that processes RAW files so I haven’t experienced this, but it seems common sense to me. Big file size isn't the only problem with raw though.

ISO Standardization

I *think* the other problem with *.raw files is that it can sometimes be a pain to manipulate them. From my understanding, *.raw files vary between camera vendors so a *.raw on an old professional Single Lens Reflex (SLR) Kodak Camera may not necessarily be in the same format as a *.raw file on a professional Olympus SLR. If you have some sort of batch processing that you need done on a large number of *.raw files from various cameras, then you would probably have to go through the effort of not only determining to which camera each *.raw file belongs but also get a tool that can update those *.raw files. In certain situations that could be a bit of a mess. That mess could totally be avoided if more camera vendors were to replace their *.raw formats with the JPEG XR ISO Standard (2)(3).

Improved Color Support and Pallet

As if the ISO Standardization, lost cost and excellent compression of JPEG XR wasn't enough to convince hobbyists to consider using JPEG XR as a poor man's version of RAW, there is the fact that JPEG XR has a much better color depth than JPEG and maybe even JPEG 2000. Assuming I interpreted her correctly, Ms. Grunin seemed to imply that back in 2008 both JPEG and JPEG XR only supported 8 bits per channel for a total of 24 bits on a three channel image (5). In contrast, JPEG XR seems to support 16 bits per channel additive RGB for 48 bits per pixel and a more advanced 64 bits per pixel CMYK subtractive color (1)(6). Note that while I haven't personally had the privilege of dealing with high end printing equipment that needs CMYK treatment, I think that JPEG XR could be useful in a print shop environment where subtractive color is more of an issue.

Transparency and Tags (Bye-bye PNG...)

Other key features of JPEG XR that are important to me personally, are translucency and the ability to embed tags in the images. I group these features together because when combined with the excellent compression rate of JPEG XR, they allow me to use JPEG XR as a replacement for PNG. As you know, JPEG already allows metadata to be easily planted into images, but when is the last time you have been able to reliably do that with a PNG? PNG *does* allow tEXt chunks to be embedded into images (7), but those chunks can not be read or written to via *most* image editing programs. Because of the lack of support for PNG tEXt chunks, it may or *may not* be useful for you to embed data in them. In contrast, JPEG XR like JPEG allows metadata to be easily embedded in the file and that metadata is easily read or updated by modern versions of MS Windows. The tagging, translucency and compression features of JPEG XR reduce the need to rely on PNG.

Concluding Remarks

So your probably wondering why I am blogging on this if I am so sold on JPEG XR. Since I am so sold on JPEG XR, why don’t I just use it and move on? Well I am using it as best I can but there are a few third party hiccups. As of the writing of the blog entry, neither FireFox 20.0.1 nor Chrome 26.0.1410.64m seemed to support JPEG XR. I find that lack of support a bit amusing since the format:

  1. is widely supported in MS Windows (1)
  2. the format is supported by the latest version of Flash (1)
  3. the format is an ISO Standard as mentioned above (2)(3)
  4. Microsoft released the JPEG XR Standard under a Microsoft Open Specification Promise back in 2007 (8)
  5. on April 2013, Microsoft released a BSD Licensed open source JPEG XR Library (1)

With all of the advantages of JPEG XR and the efforts Microsoft has made to make the standard publically accessible, I can't image why so many pure "Open Source" giants still appear to be resisting its adoption. I think this standard has been around since 2007 (1), so what's the holdup? If any groups are *still* resisting the adoption of JPEG XR, I fear they may be doing so to the general public's detriment.

(Maybe we should all keep our fingers crossed that the new April 2013 released BSD JPEG-XR library knock down the walls of acceptance once and for all...)


1. Various.
Wikipedia. [Online] APR 16, 2013.
[Cited: APR 23, 2013.]

2. Crow, Bill.
JPEG XR is Now an International Standard
MSDN Blogs: Bill Crow's Digital Imaging & Photography Blog. [Online] July 30, 2009.
[Cited: APR 23, 2013.]

3. Sharpe, Louis etc al.
Press Release - 49th WG1 Sardinia Meeting:
JPEG Committee Issues Call for Advanced Image Coding Technologies
[Online] July 17, 2009.
[Cited: APR 23, 2013.]

4. Microsoft.
JPEG XR Codec Overview
MSDN: Windows Developer Center - Desktop[Online] November 29, 2012.
[Cited: APR 23, 2013.]

5. Grunin, Lori
Could JPEG XR deliver cheaper, better burst shooting?
CNET Crave [Online] February 6, 2008
[Cited: APR 23, 2013.]

6. Various.
CMYK Color Model
Wikipedia. [Online] APR 11, 2013.
[Cited: APR 23, 2013.]

7. Various.
Portable Network Graphics
Wikipedia. [Online] APR 11, 2013.
[Cited: APR 20, 2013.]

8. Various.
Microsoft Open Specification Promise
Wikipedia. [Online] March 17, 2013.
[Cited: APR 20, 2013.]

©2013 - Shawn Eary
This post and all included code is released under the Free Christian Document License (FCDL)