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Spectrauma : notes on the feature film

Spectrauma on IMDb

DCI mastering and DCP delivery for the indie feature Spectrauma

This article details the post and DCI mastering workflow used for the indie feature Spectrauma.  Hopefully it can guide other indie filmmakers on their journey to DCP delivery. After much troubleshooting, we recently witnessed the successful ingest and playout of our Digital Cinema Package (DCP).

If you want to see firsthand the stunningly high cinema quality possible with features made for under $70K then attend one of the upcoming screenings.

View Trailer:

The majority of the the film’s footage is Red One material (99%). There were only a couple shots originating on DSLRs; some Nikon .NEF sequences and Canon 5D. (Although the 5D has better skin tones than the RED, overall the 5D material does not hold up well for cinema applications in my option.)

Having previously only worked with photochemical film and DI, the digital origination and exhibition were new territories for me. So I choose to work in a “film centric” mastering workflow. (See the workflow diagram below.) The really cool aspect to this is that one can grade in film density space (Log) while seeing the result as it would print on Kodak Vision Premiere stock (2393) - in DCI-P3 grading monitor.

I created three 3D LUTS:

  1. Log PD → Kodak 2393 → DCI-P3 R’G’B’ (2.6 gamma)
  2. Log PD → Kodak 2393 → Rec. 709
  3. Log PD → Kodak 2393 → DCI X’Y’Z’

In the LUT profile, I used Arri ‘Carlos’ density aims, which are slightly different from the Kodak recommend aims of their intermediate stock. The reason being is that if ever we decided to do a 35mm film-out, most facilities use the Arri Laser density aims. [We did actually film-out the trailer, BTW] The first LUT is for grading in DaVinci Resolve while outputting to the HP DreamColor set in P3 mode. The second is for making HD video versions – conform checks, etc. The third LUT is used to convert from film printing density (PD) to DCI colorspace for the final DCI DCDM (.TIFF sequence).

.DPX (Log PD) → {LUT} → .TIFF (DCI X’Y’Z’)

With this method, the entire color gamut of the Kodak 2393 filmstock (as illuminated by a Xenon lamp) is precisely encoded into the DCP – even colors which fall slightly outside the P3 triangle!

The film was maintained in five (5) reels throughout post. However, the Qube software we used was limited to a single composition per play-list.  Higher-End versions allow one to create separate MXFs for each A/V reel.  Being on an ultra-low budget, the Qube eXport plug-in for Compressor was the only thing within reach. Well, it worked great!   It should be noted that one could still make individual DCP reels with this plug-in, but a separate software tool is required for concatenating/repackaging the show as a cohesive feature. In situations where producers wish to change scenes late in post, then only the affected reels need re-encoding.

File-system madness. The Qube eXport will generate a DCP within a folder, but the digital cinema servers like to see all the package assets on the disk drive’s root. We struggled for awhile to get the theatre’s Qube server to recognize our drive. We made NTFS, EXT2 and EXT3 versions. It is important to use MBR (Master boot record) and only one partition on the drive. We had mistakenly used GPT on the Linux EXT2 drive and then re-made it as MBR. However, by then the NTFS drive was ingesting. The other gotcha we discovered is that the Qube Server’s front panel USB port was version 1.1. After many attempts with “nothing to ingest” errors we tried the back-panel USB ports, which are indeed version 2.0 and finally worked as expected.  The preferable method is to use eSATA connections offered on the server.  In the future, we’ll do that instead.

For mounting EXT2 drives under Mac OSX (our post environment), we first tried Paragon Software’s ExtFS, which works fine when tranferring small files. Our DCP’s video MXF file, however, would never tranfer to the target EXT2 drive. So we ended up using Google’s (free) MacFUSE. More details on using MacFUSE are found here.

I’ve skipped over much of the audio post here. But briefly; I exported audio OMFs out of FCP for each picture-locked reel. These where then imported into Pro Tools for all subsequent sound post. Reference and operating levels where set such that -20 dBFS (decibel below full scale) pink noise outputs at 85 dBc SPL (per DCI spec - same as Dolby Digital and Sony SDDS printmaster guidelines), along with the Small-room X-Curve (SMPTE 202M, ISO-2969) for the B-chain frequency roll-off.

The Egyptian Theatre’s Barco projection looked EXACTLY as I had graded on the HP DreamColor. Huge thanks to GW Hannaway & Associates and Landmark Theatre’s wonderful staff!


Feel free to contact me via email with any questions – mindcine [at] gmail [dot] com


Spectrauma Editing

Cutting Spectrauma’s six reels down to a taut five!