ISDCF held a Plugfest (early June) in its ongoing review of industry readiness for SMPTE DCP-packaged distributions. If the goal is to convince distributors that equipment in the field can play SMPTE DCP distributions as well as they can play Interop DCP distributions, then the industry still has a way to go. Based on comments made by major distributors, it was evident at the June 5 ISDCF meeting that the goal had not been reached. The next Plugfest was scheduled for November.
ISDCF has an impressive list of areas that it evaluates in regards to SMPTE DCP packages:
1) Picture and sound
2) On-screen subtitles
3) Off-screen subtitles and captions (closed subtitles and captions)
4) Audio routing of HI/VI channels and of the 7.1 format
6) 3-D on-screen subtitles
Progress is incremental. Texas Instruments recently fixed a on-screen subtitle synchronization problem in DLP Series 2 projectors, which performed well at this Plugfest. But synchronization issues continue to occur under certain conditions with SMPTE-compliant on-screen subtitles, which is not acceptable to distributors. Distributors want to know that SMPTE compliant content, regardless of the options employed, will play.
In the course of the June meeting’s dialog, it became apparent that the manufacturers of off-screen closed caption systems were ignoring the use case for off-screen subtitles, a content label included in the SMPTE specification that is differentiated from off-screen captions. This will likely be cause for the generation of test content that fully exercises the SMPTE specifications for off-screen content.
No audio routing problems were reported this round. But this is likely to change, for the worse. SMPTE DCP focuses on the compactness of audio track files, introducing complexity in the media block to achieve this. In comparison, the Interop approach achieves the least complexity in the media block for audio. Notably, the Interop method does not require the media block to route audio.
The difference between SMPTE DCP and Interop DCP regarding how audio is handled is not subtle, and the problems caused by this difference are destined to grow. SMPTE is about to publish the latest revision of SMPTE 429-2, the top-level specification for SMPTE DCP, which extends the previous version of SMPTE DCP with the ability to order audio channels in any order whatsoever. This new “feature” places new and more complex demands on audio routing in the media block. It’s questionable that any manufacturer supports this capability today. The kicker in this is that the demands placed on audio routing by SMPTE do absolutely nothing to enhance audience experience. It’s an easy bet that the future success of SMPTE DCP will be decreased by the increasing complexity of SMPTE’s audio track file specification. ISDCF has not performed any tests towards compliance with the latest version of SMPTE DCP, leaving most people in the dark as to what lies around the corner.
Even without the problems introduced by audio, ISDCF has its hands full evaluating all aspects of SMPTE DCP interoperability. It is proposing to test content produced by various mastering systems, a step that is worthy of applause. It may surprise readers to learn that there is no compliance testing process for digital cinema mastering systems, Interop DCP or SMPTE DCP, which has caused many problems in the field. Public evaluation of these products will be a significant step forward for digital cinema.
Last but not least, ISDCF is taking solid steps to push forward its composition metadata draft, an XML approach intended to eliminate need for the clumsy Digital Cinema Naming Convention. It’s actions in this area could lead to a new work effort in SMPTE 21DC. Recent changes have been made to the draft which please your author. A new element array that will allow inclusion of multiple content identifiers was added, providing a placeholder for those interested in automating in exhibitor back office systems the steps involved in the reconciliation of bookings.