Crave

(Credit: Lori Grunin)

When Canon's Chuck Westfall popped by last month to give us a sneak preview of the EOS Rebel XSi, I expressed my disappointment that the camera's raw continuous-shooting maxed out at a mere 6 frames. I asked Chuck if there was anything on the horizon that might deliver a better raw burst-shooting experience for the can't-afford-a-Mark-III set. His immediate and somewhat unexpected response: "JPEG XR." A few weeks later, I put a similar question to Casio's Scott Nelson, a product manager in the camera division, as he showed off the company's burst-mode blitzkrieg, EX-F1--a camera which doesn't support raw for burst shooting. He, too, indicated that JPEG XR held the key for delivering higher-quality, high frame-rate photos at reasonable prices.

Never let it be said that I couldn't recognize a trend once it whacked me on the head a couple of times.

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. Furthermore, while JPEG-processing chips are cheap, the proprietary nature of raw files makes it necessary to use dedicated silicon for processing them with any speed. That's a lot of cost to add to a sub-$1,000 dSLR or enthusiast shooter.

Microsoft's JPEG XR--the XR stands for "extended range"--provides some of the image-quality benefits of raw while offering the smaller file size and non-proprietary processing benefits of JPEG. Keep in mind that JPEG XR doesn't replace raw. It simply offers better compression algorithms, and a wider dynamic range than JPEG. At best, one might find a JPEG XR photo visually indistinguishable from a processed raw file. That lets it stand up to retouching better--suffer from less degradation--than its predecessor. For shooters in that market segment, that may be enough.

Clearly, no one's talking about actual products yet, and JPEG XR-as-standard hasn't even attained Committee Draft status within the ISO's JPEG committee (that's scheduled for the end of March). But the fact that I'm actually hearing about it in conversation makes me think that we might start to see some implementations by next year. While I still would prefer longer raw bursts, JPEG XR strikes me as a reasonable compromise.

Update: I clarified the caption of the illustration to better indicate what editing had gone on to produce the side-by-side images.

Microsoft has taken the beta tag off a plug-in to let Photoshop read and write files in the HD Photo format, which Microsoft is standardizing as JPEG XR.

The free plug-in is available for download for Windows and Mac OS X systems. The plug-ins work on Windows XP and Vista, Mac OS X 10.4 and 10.5, and Photoshop CS2 or CS3, Bill Crow, who's overseen the HD Photo and JPEG XR effort, wrote on his blog Thursday.

These two images both are edited versions of overexposed originals. After editing, the overexposed JPEG version on the left looks murky. The right picture, originally encoded and then edited as an HD Photo, has more dynamic range, so detail in the highlights can be recovered better. It's shown here converted back into regular JPEG after the editing process.

(Credit: Microsoft/Bill Crow)

Microsoft hopes HD Photo eventually will replace the ubiquitous JPEG standard overseen by the Joint Photographic Experts Group. Among the HD Photo advantages that Microsoft touts: it offers more efficient compression, richer color and a much wider dynamic range; it can optionally store images without data loss from compression; it's free of royalty and licensing constraints; and it can run in camera hardware. Support for the file format, initially called Windows Media Photo, is built into Windows Vista.

HD Photo also can be used to show images online at different resolutions, transmitting only the portion of the image that's shown on the screen. That's useful for zooming in to a high-resolution photo without having to download a vast image, a technology Microsoft uses in its HD View software for viewing detailed images online. One organization using HD View is Xrez.

However, Microsoft faces significant challenges in encouraging adoption of the technology. Building it into Vista is a big step, and an endorsement from Photoshop publisher Adobe Systems helps, but JPEG is deeply entrenched. Standardization through JPEG could encourage industry players to adopt the standard--in particular those who are leery of Microsoft's power.

But there are plenty of standards that never catch on. What could really tip the balance in favor of HD Photo/JPEG XR is if it gets built into cameras directly so photographers can start using it from the outset.

The final version of the plug-in, developed in part by Pegasus Imaging Systems, looks mostly like recent betas, Crow said.

"All the changes we've made since the last beta are under the covers, fixing a couple minor bugs, addressing several theoretical security vulnerabilities and generally bringing the code up to current Microsoft standards for released software," he said. "Don't forget that the beta versions will expire on December 31st, so you should definitely download and install these new released versions."

A new attempt to provide a higher-end sequel to the ubiquitous JPEG image standard is officially under way.

The multiple countries participating in the Joint Photographic Experts Group, which created the JPEG standard, have approved an effort to make Microsoft's HD Photo format a standard called JPEG XR, said Bill Crow, who has led Microsoft's HD Photo effort and who just took over the company's Microsoft Live Labs Seadragon imaging project. XR stands for "extended range," a reference to the format's ability to show a wider and finer range of tonal gradations and a richer color palette.

"The country vote is done, and it passed," Crow said. "That means the International JPEG committee has decided to go ahead and create the standard. Now it's just a process of doing that work," a process that will begin later this month in a meeting in Kobe, Japan.

The move is an important step in the transformation of the photo format from an in-house technology called Windows Media Photo to a neutral format more likely to be palatable to companies that don't want to be beholden to Microsoft.

However, the move also means that Microsoft will have to be more patient with its hopes to get HD Photo to catch on more broadly. Standardization "typically takes around a year," Crow said.

The wait is worth it, said Josh Weisberg, director of digital imaging evangelism for Microsoft's Rich Media Group.

"As much as I would love to have more support for it, I think it's logical for people to wait for there to be a standardized version of it," he said. "If we weren't going through the standardization process, we'd be pushing much harder for people to support it."

In Microsoft's view, HD Photo also offers better compression and support for in-camera image processing. It's built into Windows Vista, but Microsoft offers the software development kit to implement the technology free and with no royalty constraints. Image-editing powerhouse Adobe Systems has voiced support for the format.

Microsoft announced some significant progress Tuesday in getting its HD Photo technology standardized as JPEG XR, a significant development for photographers like me who don't like the idea that their camera is discarding data when it converts image sensor information into a JPEG.

But the arrival of a higher-quality alternative to conventional JPEG could mean a bit of a turf war between Microsoft and Adobe Systems, which is trying to popularize a file format called Digital Negative (DNG). DNG is, in part, an attempt to bring some order to the chaos of proprietary "raw" image formats that higher-end cameras produce, giving photographers access to sensor data that hasn't been boiled down into a JPEG.

(Credit: Adobe)

Microsoft positions JPEG XR chiefly as a higher-end replacement for JPEG, but in talking to Robert Rossi, Microsoft's principal program manager for emerging image and video technology, his opinions about JPEG XR's relation to raw and DNG jumped out at me.

Adobe's vision for DNG is that increasingly sophisticated software will take the hassle out of processing raw images, enabling DNG technology to spread more broadly. But Microsoft seems to believe JPEG XR will handle the needs of enthusiasts demanding more quality.

With JPEG XR, "You're giving people much of the capability of raw in a convenient file format. On the ultra-high-end there might be still a preference to use raw," Rossi said.

DNG has "a far more limited market or focus," Rossi added. "We are kind of approaching the raw/DNG functionality, but we would go much lower into the prosumer and consumer market, all the way down to cell phones."

Ed Lee, an analyst with InfoTrends, sees some competition between DNG and JPEG XR. "I think some of it comes around to who does the better job marketing the format and getting it adopted," he said.

Personally, I'd welcome a little competition among powerful companies trying to improve image quality, as long as the world isn't saddled with two competing standards that do the same thing. But although there's definitely some overlap, I suspect the two formats will remain more in separate domains--and not just because Adobe spoke positively about JPEG XR earlier this year, indicating it doesn't feel too threatened by JPEG XR.

If it fills Microsoft's expectations, JPEG XR will be used in a much larger, mainstream photography market. DNG and raw, in comparison, appeal chiefly to professionals and advanced amateurs today, and no matter how easy processing those images may become once downloaded from a camera, any amount of processing will rule out a large population.

JPEG XR does address one advantage of raw and DNG, the ability to preserve more of the original data from image sensors. JPEG retains 8 bits of data for the blue, red and green in each pixel, but cameras typically record 12 bits, with Canon's new 1D Mark III recording 14 bits and higher-end models 16 bits.

JPEG XR, though, has immense bit depth--with 16 or 32 bits of data recorded for each pixel's color, that means somewhere between 65,536 and 4,294,967,296 shades of tonal variation between black and white. Thus the "XR," or extended range, moniker. Regular 8-bit JPEG has 256 shades, which is plenty if they happen to be distributed perfectly, but not enough if you want to use photo-editing software to brighten up a face that's lost in shadow.

However, DNG and raw formats offer something JPEG XR can't: unprocessed data. Creating a JPEG XR image means the camera is making its best guess about color balance--compensating for the bluish hue of fluorescent lights or the orange cast of incandescent, for example--as well as reducing noise and sharpening edges. For those who want that level of control, stick with raw or DNG.