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Are you created mosaiced or linear DNGs? My understanding is that OS X (and hence Aperture) do not recognize linear DNGs.
I am creating simple mosaiced DNGs according to 220.127.116.11 specification. They are not interpolated (not linear).
Do other DNGs work on your system?
You didn't include on your list that it's possibly a bug in Mac OS.
(Apple) Digital Raw 2.2 has some issues with DNG. Did you install the Digital Raw 2.2 update?
Yes, I am sure it is a problem with the Mac version of the Adobe SDK for the following reason:
Other DNG files appear just fine. For example, the Adobe DNG Converter for Mac program produces DNG files that have no such problems. Since Adobe can do it with their converter software and not with their SDK, it must be their SDK.
Also, I have the latest Digital Raw from Apple (2.4?), as I updated everything to the latest levels.
David, it is highly unlikely to be a problem with the SDK. The Adobe DNG Converter (and Camera Raw, and Lightroom) also use the exact same SDK, on both Mac and Windows.
I am guessing you may be writing out a DNG without some of the original metadata that OS X is looking for (perhaps make/model of camera?)
No, that is not the case. I have indeed added the make and model of the camera, and it matches exactly the same fields of the dng file created by the Adobe DNG Converter, as shown by the dng_validate program.
I think it would help if you could post a simple skeleton program that can indeed use the dng sdk (Mac) to create a dng file that would show a thumbnail and preview. Only then, will you see that it is not working. Or, if you are indeed successful, then we will learn what Mac OS X is looking for.
> we will learn what Mac OS X is looking for
That's exactly the problem--it shouldn't be looking for anything. The thumbnail is always in the same place, and the preview is a standard JFIF stream. I can see where Aperture would possibly have issues once it gets to the sensor data--some folks are a bit paranoid when coding up their RAW processing engine and will only accept recognized cameras--but that shouldn't prevent thumbnails and previews from being available.
If no applications on any platform can open files and find the thumbnails or previews, then that _would_ be a problem in the SDK.
If the issue is that some apps from Apple fail to open valid files that can be opened in other apps on the same or other platforms, then that's not a bug in the SDK. The place to follow up would be in Apple's developer email lists. Perhaps an Apple employee can let you know how to work around the issue.
A better bet would be to figure this out on your own. Even if you identify the issue, big companies take forever to release bug fixes due to their long and bureaucratic development processes. Try generating your file with the SDK, then reprocessing with the DNG converter, and then use a tool like exifprobe to compare your file from the SDK with the one from the DNG converter (which presumably does work with Mac OS). I spend a significant amount of my time doing this kind of analysis with RAW formats. It is just par for the course when working with RAW files.
David, running dng_validate with the -dng command-line option will output a DNG with an embedded preview. You can trace through the code to see exactly how & where that preview is embedded, as well as how the DNG is constructed from the negative data structure, how the image & tag writer operate, etc.
Perhaps you can post one of your DNGs that is giving you trouble and we can take a look at it.
An example image is given below. The first one (test.dng) is the image we created with the Adobe DNG SDK on a Mac. The second image (test_dngv.dng) is the result of running it through the dng_validate program (which uses a compressed image by default with the -dng option), and therefore much smaller in size.
Neither of these images produce visible thumbs or previews on the Mac (not in any of the Apple programs such as Finder, Preview, Aperture, iPhoto etc.). However, when placed onto a Windows machine, they appear just fine everywhere.
As the previous poster has indicated, this may not be the fault of the Adobe DNG SDK, but for all practical purposes it is a hindrance to us. Whoever is at fault, the bottom line is that the DNG format is proving to be less portable than other image formats such as TIFF or JPG. We have no problem moving these other formats from any computer to any other computer, whether it be Mac or Windows. We are trying to support Adobe and its efforts with new standards, but this is costing us valuable engineering time in dealing with these matters, that just do not exist with other formats.
And, I apologize if this is presented in the wrong forum. However, we would appreciate if you can help us in this matter. Obviously, it can be done, since the Adobe DNG Converter program is capable of generating dng files with proper thumbs and previews on a Mac. It is just not documented anywhere for developers trying to work with the DNG SDK.
The preview for both of those files shows up very nicely in the Finder on my Mac.
As for the thumbnails on the DNGs icons themselves, I've never seen any on any DNG in the Finder, but I have only a couple of dozen DNGs to test.
What version of Mac OSX are you running?
Tiger 10.4.11. Photoshop 11 (CS4).
Dual bootable, DP MDD 1.25GHz G4 (2004), maxed out at 2GB of RAM, both Spotlight and Dashboard disabled, Photoshop primary scratch disk on dedicated 160GB internal drive, at least 100GB available on each of the four internal drives, up to 300GB on some. Counting external FW drives just over 1TB of drive space available. nVidia GeForce 7800 GS 425MHz 256 MB graphics display card. Processor napping enabled through CHUD 3.5.2.
David, the Make and Model of both of these DNG files is "Adobe" and "DNG", respectively. These are certainly __not__ the make and model data produced by the Adobe DNG Converter.
I am guessing that OS X Leopard is looking for make and model from the original manufacturer (or other such metadata). For example, if I process a Nikon D3 file through the Adobe DNG Converter, then run dng_validate, I get:
Make: "NIKON CORPORATION"
Model: "NIKON D3"
I suspect this is an issue with Apple's DNG implementation.
First, we were playing around with these make and model fields, and none of them worked (including the exact make and model from the camera manufacturer, and we even matched what was produced by the Adobe Converter program).
If you wish, we can restore these fields and re-post the images to prove this to you. However, even the previous poster, Ramon, is able to view these images on his Mac despite these fields, but which is a G4 Tiger system. We have no doubt that it may work on that system, however, it is NOT working on Intel based Leopard systems.
I think the preview in finder is the DNG thumbnail based on its size, but I don't know for sure.
I can see a thumbnail sized image in Finder on an Intel Mac with 10.4.11.
If I ctrl-click on the file and choose open with Preview (Photoshop is my default), then it tells me that the file is either corrupt or an unrecognized format.
An interesting test would be to take a working file created using the previous SDK, reprocess it with updated dng_validate, and then see if the output DNG file doesn't work. We need working and non-working versions of the same file in order to determine what the difference is.
Thank you David and Eric.
I will create the files shortly, and be careful to make them identical (as possible). Hopefully, you can see why one works and one doesn't. Nothing given by the dng_validate program was able to help us, but it is possible we have developed tunnel vision by now.
OK, I have posted our best effort dng file creation on Mac Leopard, one that matches as closely as possible what we can get form the Adobe Converter program. The image test_AdobeSDK.dng is the one we created with the Adobe DNG SDK, and it still does not show thumbnail or preview on Mac Leopard systems. The other image test_AdobeConverter.dng is the one created from the Adobe DNG Converter program, on the same Mac system. This image properly displays the thumbnail and preview on Leopard. Can you tell me why this is the case?
I noticed that the first one (the one whose thumbnail doesn't show up in Leopard) is missing AsShotNeutral / AsShotXY tags. Can you try adding at least one of these? (Feel free to just copy the tag from the 2nd file.)
Eric, we just tried adding the AsShotNeutral tag, and ..... now suddenly everything works and all the Apple programs acknowledge the dng file. I wish this tag was documented more clearly, since Windows PCs do not seem to care about it, but nevertheless we are grateful for your help. Thank you.
> I wish this tag was documented more clearly, since Windows PCs do not seem to care about it
How is this a documentation issue?
How exactly is the specification of a file format responsible for documenting any shoddy implementations?
Right. Thank you for being so helpful.
David K, it is technically legal for a DNG file to omit both the AsShotNeutral and AsShotXY tags. Thus, your original DNG without these tags was actually valid. Obviously, in practical cases we don't recommend this, because that means the DNG processing application (e.g., raw converter) won't know what the as-shot white balance is.
I am guessing that Apple's DNG implementation (mistakenly) treats the absence of both of these tags as an indication of a corrupt or invalid DNG and hence decides not to render previews.