The SMPTE 21DC Technology Committee for Digital Cinema met this month in Germany at Fraunhofer’s facilities. The “backwards slash” documents passed ballot and were voice-voted forward for publication. This set of documents consists of ST430-4 Log Record Format Specification, ST430-7 Facility List Message, ST430-9 Key Delivery Bundle, and ST433 Datatypes. The changes made in these documents are not substantive for the most part. A namespace used in the schemas described in each document had errors. These errors should have been fixed several years ago in real products. It is worth commenting, though, that it took a few years for these corrections to make their way through SMPTE. (Well, not quite through SMPTE. It could take until early next year for these changes to actually make their way to publication.) There are always reasons why so much time was necessary. Keep that in mind as you read this report.
Another footnote about progress in new documents: ST0429-2-2011 is now (or will soon be) released in the SMPTE store. 429-2 is the cornerstone of the SMPTE DCP. This revision brings new clarity to timed text applications, and introduces the “wild track” and “7.1DS” audio formats. This revision has been in progress almost since the 2009 version was released.
New work was launched to study – you guessed it – high frame rates. In six months, the new High Frame Rates for 3D and 2D D-Cinema Applications Study Group is to produce a report outlining “the elements of the d-cinema distribution system that are impacted by an increase in the frame rate of 3D content to 48, 50, or 60 fps per eye (edit units per second), or 2D content to 96, 100, or 120 fps total.” The study will look at visual artifacts at higher compression rates. In commentary, this group has its work cut out for it. Generation of, or obtaining the rights to, quality content for the testing of multiple bit rates and frame rates is not a trivial undertaking. It requires sponsorship. Whatever this group does, its output will have little if any impact on the release the Hobbit in December 2012. It’s possible, but unlikely that it will have an impact on the sequel to Avatar. If this work is important to studios, then this group will move forward smoothly. If studio attitudes should change, though, this group will have a difficult time completing its tasks.
Not reviewed in this month’s meeting were the proposed redlines for updating to the SHA-256 hash used in digital signatures. These redlines are in discussion in the NIST Revision Ad Hoc Group (a document writing group). The documents under consideration for revision are ST 0429-6 MXF Track File Essence Encryption, ST 0429-7 Composition Playlist, ST 0429-8 Packing List, ST 0430-4 Log Record Format Specification, and ST 0430-5 Security Log Event Class and Constraints. These proposed changes stem from changes made to NIST FIPS 140-2 in early 2010, and the NIST timetable for hash algorithm transitions published in NIST SP 800-131A Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths. According to SP 800-131A, the SHA-1 algorithm in use in the previously named SMPTE documents must be upgraded to SHA-256 by end-of-year 2013. Given that it takes 2 years to change a slash mark in SMPTE, one would think that this work would be in high gear today. However, it is being treated without concern. DCI’s consultant, Tony Wechselberger, has shown no urgency in resolving how to change documents, and how to enable this transition in the field. More discussion on this in the DCI section of this report.
Also not reviewed in this month’s meeting is the substantial progress being made in the 3-D Subtitling Ad Hoc Group. This group is producing a redline of ST 0428-7 Subtitle. As the scope of the group includes subtitle and caption rendering behaviors, it may have to update additional documents. More on the reasons behind this in the ISDCF section of this report.