The 21DC working groups and other sub-groups met end of month on August 31. A plenary session of the 21DC Technology Committee is scheduled for September 17 in Geneva, Switzerland.
Last December, the CSP/RPL protocol for synchronizing out-board closed caption systems, passed all ballots in SMPTE. The protocol is described in SMPTE documents S430-10 Aux Content Synchronization Protocol, and S430-11 Aux Resource Presentation List. Following that, a bizarre occurrence prevented them from being published, and required the 21DC committee to take further action. Nine months later, S430-10 is moving forward to publication, and S430-11 is about to complete a ballot that will lead to publication.
This was no small feat. S430-11 references another 21DC standard, S433 Datatypes, which harbored the problem of defining inconsistent XML namespace names. Think of this as an instruction to the closed caption system as to which version of standard is being used. There were elegant and inelegant ways to address the problem. Inelegance won in the end as the elegant way would have interrupted DCI compliance testing. But the process of making that decision took six months. Then the July ISDCF Plugfest uncovered problems with all closed caption systems (as well as open caption displays). It took another month to determine that the CSP/RPL protocol was not to blame, during which time the standards were put on hold.
All together, four other SMPTE documents are also affected by the S433 error, including the FLM and the security log standards. The 21DC committee is in process of updating five documents, including S433.
The Audio Channel Labeling ad hoc group met for its first time August 31. This group has the memorable S428-3 Audio Channel Mapping and Channel Labeling document on its plate to revise. Audio is the last area of digital cinema to get its due attention, and S428-3 has much room for improvement. The intended results of this effort will define a new way of distributing audio such that each channel/speaker location is labeled. By doing so, any combination of channels can be included in a distribution, eliminating the need to distribute in pre-defined standard audio formats. In turn, the media block can route the labeled audio channel to the speaker of the exhibitor’s choice. Sony’s Brian Vessa chairs the group.
With the Audio Channel Labeling ad hoc group underway, the DCDM Metadata group will resurrect. The goal of this group is to define metadata that will help streamline the mastering process.
The revision of S429-2 DCP Constraints is progressing. This revision will institute a “wild track format” of 16 unlabeled channels for testing and other purposes. It will also define the 7.1 DS surround sound format first released with Disney’s Toy Story 3. What should be the last debate before the draft is finalized is the representation of duration of a reel in the CPL (Composition Playlist), given that timed text tracks will not start and stop at the same times as sound and picture.
While significant activity continues to take place in SMPTE 21DC, the volume of activity is diminishing. This is a good sign. 21DC today has two working groups under which most activities had once been conducted. Sometime in 2011, these working groups will likely be retired, with all sub-group activity reporting directly to the 21DC Technology Committee. The only difficulty this change will pose will be due to a peculiar SMPTE rule, requiring 21DC Digital Cinema TC plenary sessions to be held in conjunction with those unrelated broadcast standards groups. This causes 21DC TC plenary sessions to be held in various places of the world, where few if any cinema experts can attend.