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New DNG features & FPV codec compatibility

PostPosted: Tue Jan 17, 2012 7:41 pm
by HotShot
Hello,
a short note "FYI":

The beta version of Adobe Lightroom 4 brings novelties to the DNG format:
- new "Camera Raw 6.6-compatible" DNG format. >> FPV Codec displays them fine so far (be it overviews or full decode)
- embedding of "Fast Load data" in any DNG file >> incompatibility with FPV Codec & causes COM Surrogate / Explorer crash
- optional "Lossy Compression" in CR 6.6-compatible DNG file >> incompatibility with FPV Codec too

Just wanted to let you know, in case you missed the info and before anyone starts complaining of crashes etc. :mrgreen:

To illustrate, a full set of sample DNG files here: (15.7 MB 7z archive). Tested under W7x64 SP1, codec pack 3.1.0.49

Re: New DNG features & FPV codec compatibility

PostPosted: Wed Jan 18, 2012 1:15 pm
by Axel
Thanks for the sample files. Indeed Adobe is playing with its proprietary DNG format and added a few features, undocumented to this day.

One of them confused our codec and caused the crash you experienced, which is now fixed (in FPV Codec Pack v3.1.0.52 and FPV Pro 1.7.234.0). The last published DNG spec is v1.3 and the files you submitted are still marked 1.3, despite being different. Why they did not change the format version number in the files is a mystery, and why Adobe felt compelled to invent its own proprietary JPEG variation is another...

Support for actually decoding the "new DNGs" will come at some point in the future, probably sometimes after Adobe actually publishes the specifications.

Re: New DNG features & FPV codec compatibility

PostPosted: Wed Jan 18, 2012 4:45 pm
by HotShot
Hi,
Thanks for the fast response and fix ! :)

These new features indeed generate some noise on Adobe forums. Wait and see...

Re: New DNG features & FPV codec compatibility

PostPosted: Wed Jan 18, 2012 10:26 pm
by Axel
Not reading a new (and still undocumented) format variant is not a huge deal but crashing on a file definitely is and triggers the fastest possible response from me as soon as I get a sample that reveals the problem. Thanks again for submitting such samples as they made the identification of the issue much easier.

As for actually decoding the files I'll wait until Adobe dcuments what they did and publishes the updated DNG specification (presumably 1.4).

I'm not sure how well other DNG-enabled apps cope with the new files, and Adobe could have made everyone's job easier by just incrementing the version number in the files, from 1.3 to 1.4 (or whathever) so all DNG decoders out there would know the files are different and could elect not to process them instead of opening them blindly.

The new "lossy" format is entirely different (not RAW but compressed RGB) so the change certainly granted a version number increase. Not sure about the "fast load" data, perhaps it's optional and can be ignored.