Randomize

(This was originally written in May 2006, recovered from the archives of my old blog… my opinion has not changed.)

So, rather than spending time developing software we actually need, Microsoft is coming up with their own proprietary “competitor” to the JPEG format. Some lame photographer hack was quoted on ZDNet as being in favor of Microsoft’s newest attempt to lock us into their data formats, so here’s the opinion of a programmer/photographer who has actually read the spec.

The Good

• 32-bit floating point format support for HDR.
• 8-bit and 16-bit lossless and lossy modes. JPEG is limited to 8 bits.
• CMYK support
• Optional alpha channel
• Support for arbitrary color channels that could be used for IR, distance/bump, or other information, but no direct support.
• XMP and EXIF support
• Limited to little-endian encoding and mostly integer operations (easier device support)
• TIFF-compatible headers
• Possible future support for multiple images in the same file (3D, sequential, versioning, exposure/ISO bracketing, and other applications)
• I *think* it supports the equivalent of Progressive JPEG (for display while loading over a slow connection or to a low-resolution device)

The Bad

• Storage space is CHEAP. We don’t need to store twice as many photos in the same hard drive space, especially in a format we can’t use on millions of devices that only support JPEG right now.
• The “megapixel craze” among consumer cameras (“ooh, 8-megapixel camera phone!”) will soon give way to higher quality sensors. A few more bits per pixel, better noise characteristics, better lens quality, etc. Storage space will stay far ahead of the growth rate of the average family photo.
• No support for lossless 32-bit images, so it’s no good as a professional archival format.
• No IPTC support (at least stated, may be possible via TIFF compatibility).
• No direct support for color channels with different dimensions, make the format non-optimal as a competitor for DNG (RAW files record camera sensor data directly, and most digital cameras use a Bayer pattern that has twice as many green as red or blue pixels).
• Unlike with JPEG, it would not be possible to take the red-eye out of a photo or crop it without re-encoding the entire image, lowering the quality. Now, most people who use JPEG don’t know how to do this, but it is possible.
• No support for layer transforms or partial image overlays. A future-thinking image format should support the ability to mark photo regions (facial recognition, Flikr-like tagging, etc.) and the equivalent of “adjustment layers” to allow for non-destructive edits. Yes, it would add complexity for mobile device support, but that could be removed by “compiling” the adjustments to the first image in the file and storing the original and adjustments later in the file.
• I hate DRM, copyright bits, and the like, but there should be a way to at least support the Creative Commons licensing parameters so people can state how they want their photos used.
• Breaks compatibility with the TIFF standard in unnecessary ways, such as not using the TIFF standard way of registering and identifying the codec used.

The Ugly

• As far as I can tell, no support for color management (color spaces). Even JPEG supports this!
• Proprietary
• Patent-encumbered
• Won’t get support by camera manufacturers, Apple, alternate web browsers, or Adobe
• Did I mention that your family memories would be locked into a file format that only Microsoft can give you permission to open a few decades from now?
• Update: No way to transpose a DCT-encoded JPEG file to WMP’s lossy format without further loss. There are billions of JPEG files in existance, and lack of conversion without loss is a huge stumbling block. Until this is possible, Forgent will still be extracting license fees from Microsoft and everyone else for the JPEG algorithm.

If Microsoft opens the format entirely, as ILM has done with OpenEXR, I would consider supporting it. There are enough enhancements here over JPEG and JPEG2000 to make it worth consideration, but only if color management is added and if my computer, cameras, cell phone, etc. don’t all have to have Microsoft logos on them to use the files.

Update: one fewer reason to switch from JPEG — the Forgent patent has been found to be invalid by the USPTO.