File Formats Blog

Microsoft has submitted its HD Photo image format to the Joint Photographic Experts Group (JPEG) for adoption as a standard, with the proposed name of JPEG XR. The name has potential for confusion, as the format isn't a variant of what's popularly known as the JPEG image format. (But then, neither is JPEG2000.) The format was originally known as Windows Media Photo, so Microsoft has been moving at least the labeling of the format from an OS-specific one to a general standard. Microsoft is hoping the final standard, if approved by JPEG, will be out by mid to late 2008. The company says it "will offer a royalty-free grant for its patents that are required to implement the standard."

See also the article on CNET.

Labels: JPEG

# posted by Gary McGath @ 1:51 PM 0 comments

Labels: JHOVE

# posted by Gary McGath @ 2:21 PM 2 comments

User Friendly looks at HTML 5.

It's not exactly today's news, of course. Here's a link to the main page of the W3C HTML Working Group.

Labels: HTML

# posted by Gary McGath @ 8:19 AM 0 comments

Links to an assortment of information on TIFF can be found at a new site, tiffcentral.com.

Labels: TIFF

# posted by Gary McGath @ 10:46 AM 0 comments

W3C has announced four related candidate recommendations for compound documents. These cover the Compound Document by Reference Framework (CDRF) and the Web Integration Compound Document (WICD, pronounced "Wicked"). The candidate recommendations are:

• CDRF 1.0
• WICD Core 1.0
• WICD Full 1.0
• WICD Mobile 1.0

Labels: HTML, XML

# posted by Gary McGath @ 3:29 PM 0 comments

CSS 2.1 is now a W3C candidate recommendation.

Labels: HTML

# posted by Gary McGath @ 8:59 AM 0 comments

XHTML Basic 1.1, a subset of XHTML for handheld devices, settop boxes, phones, etc., is now a W3C candidate recommendation.

Labels: HTML, XML

# posted by Gary McGath @ 10:18 AM 0 comments

The National Library of New Zealand has announced version 3.2 of its Metadata Extraction Tool. The email which I didn't receive telling me about it would have had a stern boilerplate warning against disclosing any information contained in it, so my official story is that I just found that page by chance. Honest!

The tool understands BMP, GIF, JPEG, TIFF, MS Word (version 2, 6), Word Perfect, Open Office (version 1), MS Works, MS Excel, MS PowerPoint, PDF, WAV, MP3, HTML, and XML. Unlike JHOVE, it apparently isn't intended as a validation tool, but otherwise it serves a somewhat similar purpose.

# posted by Gary McGath @ 7:00 AM 0 comments

On the O'Reilly site, Rick Jelliffe has an interesting article on ISO 8601 dates and problems with them as used in XML.

Labels: XML

# posted by Gary McGath @ 10:47 AM 0 comments

An argumentenergetic discussion is developing on the TIFF mailing list on whether BigTIFF is a new version of TIFF or a new file format. There are good reasons for calling it a new format.

At the most obvious level, no existing application to read TIFF files can read any BigTIFF file. The TIFF specification says that bytes 2-3 contain "An arbitrary but carefully chosen number (42) that further identifies the file as a TIFF file." BigTIFF files contain the value 43 in this location. The TIFF spec says that bytes 4-7 contain "The offset (in bytes) of the first IFD." BigTIFF uses these locations for other purposes, and places the offset of the first IFD starting at byte 8. In addition, a tag structure is 12 bytes long in TIFF; it's 20 bytes in BigTIFF, to accommodate larger counts and offsets.

The BigTIFF proposal calls the value at offset 2 a "version number." But according to the TIFF specification, it isn't a version but a fixed identifier. Putting a different number there is a declaration that a file isn't TIFF.

File formats do change over time, and inevitably some files based on newer versions will not be readable by software based on older versions. But it's reasonable to expect that the newer files be recognizable as incompatible or broken instances of the format. When the format's signature information, other than the part which identifies the version, changes, it's no longer the same format.

BigTIFF does have a lot in common with TIFF, and it should be possible to modify a well-written TIFF reader to read BigTIFF without too much trouble. All tag values and definitions from TIFF are retained.

It's unfortunate that TIFF wasn't designed to include version information. The only way to tell a TIFF 6 file from a TIFF 4 file is by the features (tags and data types) it uses. This puts BigTIFF in a difficult situation. But from the standpoint of format identification, it makes more sense to call BigTIFF a new format derived from TIFF than to call it TIFF, and to give it its own MIME type and file extension(s).

The decision is actually in the hands of Adobe, which hasn't shown much interest in the TIFF standard in a long time. If Adobe does nothing, then the new format isn't TIFF, since it's fundamentally different from any Adobe-approved specification. Otherwise the decision is legally in Adobe's hands.

Labels: BigTIFF, TIFF

# posted by Gary McGath @ 2:30 PM 0 comments

It's been pointed out on the TIFF mailing list that libtiff . org contains a long-outdated version of the libtiff library and is in untrustworthy hands. The location of the real libtiff library is at remotesensing.org. Frank Warmerdam writes:

Due to a slip up on our part the dns entry libtiff.org fell into the hands of DNS pirates and was sold to the current owner for several thousand euros to harvest it's positive google karma for a link farm.
 
It is out of our control. Really. Honestly. And I'd rather not angst over it any more.

About all that's to be done about it is to avoid linking to it, and to occasionally remind people that it's not a suitable place for getting libtiff code. Since it comes up first when you search in Google or Clusty for "libtiff", it is important to remember this.

Labels: TIFF

# posted by Gary McGath @ 9:06 AM 0 comments