ISDCF spent the better part of a day walking through its lengthy agenda in this month’s meeting. The highlights were the preparation of the next Plugfest, the disclosure of a working but proprietary automated key management system, and further discussion of the metadata needed of a Composition to eliminate use of the Digital Cinema Naming Convention.
Plugfest testing to date has focused on the readiness of products to support SMPTE DCP in an effort to gain confidence that products in the field are ready to receive SMPTE DCP distributions. But as questions arise as to the actual behaviors and characteristics of products, the role of the Plugfest stands to grow. Forensic audio marking is a case in point. DCI’s recent introduction of selective marking of audio channels now makes it practical to enable audio marking in servers, a feature which has been disabled in most products up until recently. Studios would like to know if it’s turned on, and if the selective marking feature is working. DCI compliance testing will answer those questions in detail with at least 16 hours of testing time to ascertain full results. In the meantime, studios will turn to the Plugfest to provide functional results. Another area where new testing will be somewhat useful is in learning how products set the signal validity bits in AES3 digital audio transports. The significance of this work is that the validity bits are the means for signaling whether audio is present, or seat motion data is present. Is has been said that most products do not set these bits correctly, and so some exploratory work in the Plugfest will be useful.
The purpose of ISDCF is to report problems, discuss and agree on fixes, and provide a productive environment for sharing new ideas and methods with the community. By providing an open environment for sharing ideas, it’s hoped to prevent duplication of efforts, and splintering of efforts. So it was with great surprise that it was “leaked” in the meeting that Regal has undertaken its own key management automation system with Deluxe, and was in progress of getting Technicolor to also implement it. The good news is that it was reported to be working very well, and that phone support for key management had dropped to zero or nearly to zero. The bad news is that Regal has no plans to share it with the industry, at least at this time. That this happened at all is the result of the tremendous failure within the industry to solve the problem in an open fashion. For example, had Technicolor and Deluxe shown an interest in working together to solve the problem, a solution could have been ready to go five years ago. While your author would like to point a finger at Regal for not playing ball with the community, there’s plenty of blame to go around.
High frame rate being the popular topic of the day, it was suggested that ISDCF conduct a trial run of a “stock” digital cinema system running at stereoscopic 60fps. Preferably, the system will be pumped up to allow a compression bit rate higher than DCI’s 250Mbs. Without looking at the quality of the picture that results, just testing the operation of a system at high frame rate would be a useful exercise. It requires high frame rate material to be packaged, and it undoubtedly requires tweaks in system software to allow the higher frames to be reproduced. The next step, of course, is to observe high frame rate content encoded at different bit rates. That step may not take place until January. Bit rate tests will evoke a quality response from viewers, and is perhaps the most important parameter to be settled for future high frame rate systems. A poll taken at CineEurope indicates that at least six in-projector media block (IMB) designs are limited to decode at a 500Mbs rate. It would be fortuitous if high frame rate stereoscopic content looks good at that rate. And if not, there will be a scramble to learn where the acceptable limit lies. The introduction of higher frame rates has implications that go well beyond the bit rate of media blocks, and is a subject that will be explored in greater depth in future reports.
One of the most interesting areas that ISDCF is delving into was introduced by Mike Radford and Al Barton of Fox. The goal of the project is to replace the unloved Digital Cinema Naming Convention with true-blue metadata that can be read by machines and displayed by GUIs in human readable form. If anything can be learned from the Naming Convention, it’s that the Composition Playlist (CPL) is short when it comes to carrying the information that users need. The project is compiling lists of metadata that should be carried in the CPL or in an auxiliary file. That’s the easy part. The hard part will be in gaining consensus for organizing the data, and for the method employed in carrying the data. But nonetheless, this is a valuable task that has been undertaken by Fox.
The next ISDCF meeting will be on August 31. The next Plugfest is scheduled for September 26 and 27.
