Digital Cinema Package

[Rainer Fritz]

Are there any open source tools for DCP playback? So that I can output it with colorspace conversion on the graphics card in RGB.... in realtime...

[ArtReaktor]

I'm interesting about decompiling DCP into RGB-pictures sequence using asdcp-test and j2k_to_image:
%OCTDIRNAME%\asdcp-test -x %OUTDIRNAME% "%SOURCEFILE%"
FOR /F %%i IN ('dir /B "%OUTDIRNAME%*.j2c"') DO %OJPGDIRNAME%\j2k_to_image -i "%OUTDIRNAME%%%i" -o "%DECODEDIRNAME%%%i.bmp" -OutFor bmp
This piece of script works just fine, but there is a serious problem i can't resolve.
Does anybody know how to obtain right color space (rgb) using imagemagic?
So, how to "invert" this line:
convert "%DIRNAME%\%%i" -alpha Off -depth 12 -gamma 0.454545 -recolor "0.4124564 0.3575761 0.1804375 0.2126729 0.7151522 0.0721750 0.0193339 0.1191920 0.9503041" -gamma 2.6 "%DIRNAME%\processing\%%i.tif
???

[Wolfgang Woehl]

Bruce Lindbloom's great pages on colorspace math list all the required steps and numbers. Basically you want to adjust reference white (which wouldn't be sRGB's D65 in a DCP's image material. It is, though, in your example above), recolor and compand to sRGB gamma.

Btw, with the linearization step in your example above ("-gamma 0.454545") the near black region got crushed beyond being recoverable and you might then indeed use "-gamma 2.2" in your X'Y'Z' -> sRGB conversion without further harm. Terrence has put some effort into building a LUT mechanism for OpenDCP which remedies the problem.

[ArtReaktor]

Wolfgang, thank you for the useful links! Now I now a little bit more about color representation technology.
XYZ to RGB conversion is quite simple. But I can't understand how to make chromatic adaptation using ImageMagick and Bruce's matrix

[Wolfgang Woehl]

Lindbloom's page on chromatic adaptation has math, methods, some important comments and common mappings. With ImageMagick you'd "-recolor" through the resulting 3x3 matrix in order to adjust reference white.

[ArtReaktor]

Unfortunately I do not have enough knowledge about color conversion or, maybe, gray matter in my head. All my experiments with Imagemagick command line and Bruce's matrix was unsuccessful. Please, help to find right pipeline to decompile XYZ .j2c to RGB .tif sequence using Imagemagick and Opencinematools.

[Julius Schall]

Hello ArtReaktor,

save the following line as a .bat file. Replace [target_directory] with your target directory (e.g. c:\tif_rgb\ ) Copy it to the directory with the extracted .tif files. And run it.

for %%F IN (*.tif) DO convert %%F -alpha Off -gamma 0.3846153 -recolor "3.2404542 -1.5371385 -0.4985314 -0.9692660 1.8760108 0.0415560 0.0556434 -0.2040259 1.0572252" -gamma 2.2 -depth 12 [target_directory]\%%F.tif

Good luck!

Julius

http://digital-cinema-mastering.com

[Wolfgang Woehl]

I'm collecting field reports about ingest and playback of encrypted DCPs and KDMs generated with dietrich/cinemaslides. See Testing encrypted DCPs and KDMs. Any tests and reports much appreciated.

Info and tests on some Sony and GDC systems would be awesome. Thanks in advance.

[ArtReaktor]

Thank you, Julius! It's exactly what I'm looking for!

[Wolfgang Woehl]

Here's a short update about some Digital Cinema related open source tools:

First of all: In addition to the nice chat here on reduser, and if you haven't already, head on over to dcinemaforum.com. It's a good entry-level resource for anything related to Digital Cinema. Run by Terrence Meiczinger, author of OpenDCP.

dcp_inspect (GPLv3) will inspect DCPs and check consistency and completeness. Basically it simulates ingest and validation, the process any cinema server must perform to make sure it has a valid package to play. One of dcp_inspect's benchmark targets was Mike Radford's awesome Fox Subtitle Test (aka Killer Reel) which consists of 3 packages actually. Mike's distribution isn't supposed to stress-test ingest but rather SMPTE subtitle implementations of various media blocks and servers. But its out-of-the-ordinary package structure made it an interesting target for ingest consistency checks. So there. dcp_inspect can be quite chatty, see http://pastie.org/2970568 for its report about the Killer Reel.

The proof-of-concept code for building encrypted packages and KDMs with Cinemaslides (GPLv3) is well-tested and stable. If you check it out please consider contributing test reports to Testing encrypted DCPs and KDMs, a server matrix which lists feedback on ingest and playback of encrypted (and signed) packages and KDMs made with open source tools.

kdm-decrypt.rb will decrypt Interop (should you ever run into one) and SMPTE KDMs if you have access to the targeted key pair. Useful for testing round-trip.

xsd-check.rb will, via Libxml and Nokogiri and in conjunction with DC related schema files schema check Assetmaps, PKLs, CPLs and KDMs.

Point dc_crypto_context.rb at a directory holding X.509 certificates and it will tell you whether the certificates found in there are SMPTE/DC compliant, chain-complete and verifyable, thus usable for signing packages. Create a proof-of-concept chain of compliant certificates with make-dc-certificate-chain.rb. You will want to tweak the code if you intend to use these in production, of course.

So all of the above are building blocks for more. Get in touch if you have questions or need a custom solution.