Exiv2

Thanks for reporting this. And thanks to Alan for his analysis. Fix submitted r4288.

Yes. I can see that the tags are there, however we don't have them registered in dngTags in src/tags.cpp

Output before the fix:

771 rmills@rmillsmbp:~/gnu/exiv2/trunk $ exiv2 -pR ~/Downloads/M28-1507_1_2016-04-25_0001_C0000_000001.dng  | grep 76
     250 | 0x8769 ExifTag                   |      LONG |        1 |      1084 | 1084
     346 | 0xc628 AsShotNeutral             |  RATIONAL |        3 |       678 | 7681/0 13200/0 1/0
     406 | 0xc763                           |      BYTE |        8 |       734 | .......
     418 | 0xc764                           | SRATIONAL |        1 |       742 | 742/0
772 rmills@rmillsmbp:~/gnu/exiv2/trunk $ 

799 rmills@rmillsmbp:~/gnu/exiv2/ttt $ exiv2 -pR ~/Downloads/M28-1507_1_2016-04-25_0001_C0000_000001.dng  | grep c7
     406 | 0xc763 TimeCodes                 |      BYTE |        8 |       734 | .......
     418 | 0xc764 FrameRate                 | SRATIONAL |        1 |       742 | 742/0
800 rmills@rmillsmbp:~/gnu/exiv2/ttt $ exiv2 -pa --grep TimeCodes --grep FrameRate ~/Downloads/M28-1507_1_2016-04-25_0001_C0000_000001.dng  
Exif.Image.TimeCodes                         Byte        8  1 0 0 0 0 0 0 0
Exif.Image.FrameRate                         SRational   1  2997/50
801 rmills@rmillsmbp:~/gnu/exiv2/ttt $ 

There are a few other tags in the CinemaDNG spec that didn't appear in the sample file:

TStop          0xc772
ReelName       0xc789
CameraLabel    0xc7a1

http://wwwimages.adobe.com/content/dam/Adobe/en/devnet/cinemadng/pdfs/CinemaDNG_Format_Specification_v1_1.pdf#page=10

exiftool includes others as well:

http://owl.phy.queensu.ca/~phil/exiftool/TagNames/EXIF.html

Alan:
Thanks I'll investigate and add those three tags this evening. I'll have a sniff around the exiftool web site at the others.

D:
Glad that you have the code build. We have a build server and it builds (and tests) the code every night on all our supported platforms (about 20). We retain "daily" builds for 60 days, every Monday's build for 120 days, and the first of every month indefinietly. http://exiv2.dyndns.org:8080/userContent/builds/

The buildserver also builds the code on 5 platforms every time we submit code, however those builds are mainly for team members to be sure they haven't broken the build. We don't preserve/publish incremental builds.

Fix submitted: r4289. I've modified the title of this issue.

Alan:
Thanks for bring the Adobe CDNG spec to my attention. We now have all 5 tags and I've updated the tag descriptions from the spec.

I see a very long list of tags on Phil's web site. One day, in that mysterious land (Mars) where there are more than 24 hours in every day, that long list should be reconciled with src/tags.cpp. However that day won't be before v0.26 code-complete in June 2016. If you believe this should be done, please raise an issue and target it for v1.0. It will be considered for inclusion in v0.27, possibly as a GSoC project and combined with #992. And we should install all of Phil's test files on the build-server and have an extended test suite that is run occasionally on the build-server.

Hi Robin! Been testing some more and somehow I cannot set the "default scale tag" in later exiv2 builds. Reason I didn,t see this before is I have been testing with a static build I found on the web from around 2014. My command looks like this. altering default scale tag will affect aspect ratio in ACR which is very useful for some dng files produced with Magic Lantern project.

exiv2 -v -M"add Exif.SubImage1.DefaultScale Rational 1/1 5/3" *.dng

From -verbose it says.

File   2/760: M28-1507_1_2016-04-27_0001_C0000_000003.dng
Add Exif.SubImage1.DefaultScale "1/1 5/3" (Rational)

Not sure if maybe something is broken on my computer. Would you mind check if you manage to set the provided default scale tag here?

D:

Thanks for the info about "DefaultScale". I'll add that in a few minutes. It will be: r4291. Your message arrived when I was about to send the following:

I've tested your command on both v0.23 and v0.24. I don't believe DefaultScale is supported in earlier releases.

545 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ exiv2 -v -M"add Exif.SubImage1.DefaultScale Rational 1/1 5/3" ~/Downloads/M*2.dng
File 1/1: /Users/rmills/Downloads/M28-1507_1_2016-04-27_0001_C0000_000002.dng
Add Exif.SubImage1.DefaultScale "1/1 5/3" (Rational)
546 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ exiv2 -pa  ~/Downloads/M*2.dng | grep -i scale
547 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ exiv2 -V | grep build
exiv2 0.23 001700 (64 bit build)
548 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ exiv2 -v -M"add Exif.SubImage1.DefaultScale Rational 1/1 5/3" ~/Downloads/M*2.dng
File 1/1: /Users/rmills/Downloads/M28-1507_1_2016-04-27_0001_C0000_000002.dng
Add Exif.SubImage1.DefaultScale "1/1 5/3" (Rational)
549 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ exiv2 -pa  ~/Downloads/M*2.dng | grep -i scale
550 rmills@rmillsmbp:~/gnu/exiv2/0.23 $ 

551 rmills@rmillsmbp:~/gnu/exiv2 $ cd ../0.24
552 rmills@rmillsmbp:~/gnu/exiv2/0.24 $ makes
make
       6      41     364
sudo make install
      95     528    6545
553 rmills@rmillsmbp:~/gnu/exiv2/0.24 $ exiv2 -V | grep build
exiv2 0.24 001800 (64 bit build)
554 rmills@rmillsmbp:~/gnu/exiv2/0.24 $ exiv2 -v -M"add Exif.SubImage1.DefaultScale Rational 1/1 5/3" ~/Downloads/M*2.dng
File 1/1: /Users/rmills/Downloads/M28-1507_1_2016-04-27_0001_C0000_000002.dng
Add Exif.SubImage1.DefaultScale "1/1 5/3" (Rational)
555 rmills@rmillsmbp:~/gnu/exiv2/0.24 $ exiv2 -pa  ~/Downloads/M*2.dng | grep -i scale
556 rmills@rmillsmbp:~/gnu/exiv2/0.24 $ 

Just listing all the tags and adding them to Exiv2 doesn't seem very difficult. However, this discussion started with 2 tags. Then Alan pointed to the Adobe CDNG spec and I added all 5 listed in the spec. And now it seems that there could be many more tags.

I'm trying to get finished with v0.26 at the moment. I think, regrettably, I have to push this issue on the backlog to be scheduled for a later release. If you, or Alan (or somebody else) can make a short definitive list of the tags to be added, I'll take care of it immediately.

Specifically, what's needed is to extend the table which I've added to src/tags.cpp for the 5 Adobe tags.

        ////////////////////////////////////////
        // http://wwwimages.adobe.com/content/dam/Adobe/en/devnet/cinemadng/pdfs/CinemaDNG_Format_Specification_v1_1.pdf
        TagInfo(0xc763, "TimeCodes", N_("TimeCodes"),
                N_("The optional TimeCodes tag shall contain an ordered array of time codes. " 
                "All time codes shall be 8 bytes long and in binary format. The tag may " 
                "contain from 1 to 10 time codes. When the tag contains more than one time " 
                "code, the first one shall be the default time code. This specification " 
                "does not prescribe how to use multiple time codes.\n\n" 
                "Each time code shall be as defined for the 8-byte time code structure in " 
                "SMPTE 331M-2004, Section 8.3. See also SMPTE 12-1-2008 and SMPTE 309-1999."),
                ifd0Id, dngTags, unsignedByte, 8, printValue), // DNG tag
        TagInfo(0xc764, "FrameRate", N_("FrameRate"),
                N_("The optional FrameRate tag shall specify the video frame " 
                   "rate in number of image frames per second, expressed as a " 
                   "signed rational number. The numerator shall be non-negative " 
                   "and the denominator shall be positive. This field value is " 
                   "identical to the sample rate field in SMPTE 377-1-2009."),
                ifd0Id, dngTags, signedRational, 1, printValue), // DNG tag
        TagInfo(0xc772, "TStop", N_("TStop"),
                N_("The optional TStop tag shall specify the T-stop of the " 
                "actual lens, expressed as an unsigned rational number. " 
                "T-stop is also known as T-number or the photometric " 
                "aperture of the lens. (F-number is the geometric aperture " 
                "of the lens.) When the exact value is known, the T-stop " 
                "shall be specified using a single number. Alternately, " 
                "two numbers shall be used to indicate a T-stop range, " 
                "in which case the first number shall be the minimum " 
                "T-stop and the second number shall be the maximum T-stop."),
                ifd0Id, dngTags, signedRational, 1, printValue), // DNG tag
        TagInfo(0xc789, "ReelName", N_("ReelName"),
                N_("The optional ReelName tag shall specify a name for a " 
                "sequence of images, where each image in the sequence has " 
                "a unique image identifier (including but not limited to file " 
                "name, frame number, date time, time code)."),
                ifd0Id, dngTags, asciiString, -1, printValue), // DNG tag
        TagInfo(0xc7a1, "CameraLabel", N_("CameraLabel"),
                N_("The optional CameraLabel tag shall specify a text label " 
                "for how the camera is used or assigned in this clip. " 
                "This tag is similar to CameraLabel in XMP."),
                ifd0Id, dngTags, asciiString, -1, printValue), // DNG tag

This is only if curious. Here is the static build which will write Exif.SubImage1.DefaultScale tag. I found it here.
http://www.l-camera-forum.com/topic/226978-tool-to-remove-dngraw-software-lens-correction-instructions/
It,s supposed to remove opcodes but inside the package you,ll find the 2014 exiv2 version. I guess I have to dig in to more recent build to check what,s happening.