On Nov 27, 11:51 am, Thomas Richter wrote:
John Navas schrieb:
[snip]
* Lastly there's Microsoft's JPEG XR (HD Photo), which is more like JPEG
than JPEG 2000 in terms of computational burden with compression
efficiency comparable to JPEG 2000, but is not yet standardized.

It's currently undergoing standardization, however, saying that it can compete with
JPEG2000 in terms of compression performance is IMHO highly overstating its powers. In
fact, from the tests performed, I somewhere sort it near or sometimes even below
baseline JPEG, depending on image content. Note that JPEG-XR is not yet final,
so things will hopefully change to the better, and that for proper tests, one
also has to check with HDR images from the market JPEG-XR actually targets at,
so beware - this is just the status quo. On the other hand, being more critical to
MS press releases won't hurt, either. The best you can do is test yourself.

I have published my own tests at the page below. My conclusion from
these (admittedly limited) tests was:

"For any given set of quality values, the HD Photo and JPEG 2000 files
were about the same size, and significantly smaller than the JPEG
file". ("Half the size" would be a fair generalisation, and at that
level probably fewer nasty artefacts). The basis for these conclusions
is at the following page - I won't repeat them he
http://www.barrypearson.co.uk/articl...ysis_lossy.htm

Until this is sorted out, RAW remains an important tool for scenes with
higher luminosity range, despite its drawbacks. I personally don't use
RAW often, but I do sometimes use it.

The major drawback is its lack of standardization. The problem seems that camera
vendors prefer to bind their customers instead of making images interchangeable.
I don't see why JPEG-XR would change their position, but that's all my guesswork.
Otherwise, it would have been easy just to approach the JPEG to standardize *some*
type of raw format - it is IMHO just not desirable for the vendors.

There IS an ISO standard raw file format. ISO 12234-2 (TIFF/EP). (It
became an ISO standard in 2001, and some manufacturers such as Canon
and Nikon based their own raw file formats on it). The problem is that
it was never really fit for the purpose of standardised interchange,
and it has become out-of-date. (In effect, DNG, also based on that
standard, is ISO 12234-2 brought up-to-date and made fit for purpose).

ISO are revising ISO 12234-2, and Adobe have given them permission to
use the features of DNG in the revision. (Just as they gave ISO
permission to use TIFF in the original version of ISO 12234-2).

Given that ISO's TC42 WG18 has responsibility for TIFF/EP, it would be
diversionary for another working group to "compete" to standardise a
raw file format. Far better, surely, for all standards bodies and
working groups to concentrate on one standard, especially if it can
based on a format (DNG) that is supported in some way by nearly 200
products of various kinds. (I would like to see the revised ISO
12234-2 either BE DNG, or be compatible with DNG sufficiently for
products to work with a common subset).
http://www.barrypearson.co.uk/articles/dng/products.htm

--
Barry Pearson
http://www.barrypearson.co.uk/photography/