From: Georg Mischler <email@example.com>
Date: October 4, 2004 5:30:55 AM PDT
The mechanics of conversion are the same for all formats, so
that's not a problem at all. The main reason why there are not
more formats currently supported is that Greg hates third party
library dependencies. The tifflib is currently the only
exception, mainly because that was (and probably still is) the
most common lossless format, which even supports HDR data
That is correct. I have experienced a lot of frustration myself, especially with OpenSource software, trying to get all the prerequisites compiled for some package in order to try it out. I have always tried to avoid this situation in Radiance by making it as uniform and self-contained as practical. The TIFF library is the only exception, and though it is well-written and portable, it still causes compilation troubles on some systems (most notably Solaris these days).
The situation of JPEG is shady at the moment, due to some
patent claims. This caused the IEEE to discuss the depreciation
of the JPEG format as an official standard. Nobody seems to
know where that will lead eventually.
Is this regarding the original DCT-based JPEG, or the new wavelet-based JPEG 2000? I hadn't heard of any patent cases related to the original JPEG, but I haven't really been paying attention to the IEEE, either. I never saw much sense in distributing JPEG as part of Radiance because if you can compile Tom Lane's libjpeg, you get cjpeg and djpeg which interface nicely with ra_ppm or (now) ra_bmp. The latter even does quick tone-mapping.
I'd be in favour of adding PNG support though, which has been
carefully designed to steer clear of intellectual property claims.
The libPNG offers a variety of losslessly compressed formats in
various bit depths. The library seems robust, and both the
specification and the API are stable. Since early this year, PNG
is also an ISO standard, so we can count on it staying around in
a backwards compatible manner for a long time.
As long as it doesn't cause hitches on different compilers, I wouldn't be opposed. I generally agree with the philosophy behind PNG, though I don't know why they didn't include a high dynamic-range format amongst their myriad encoding options.