SMPTE 21DC Technology Committee held its quarterly meeting this month, with updates to report on the several activities that are ongoing.
An amendment to 430-3 Extra-Theater Message (ETM), the core message specification for KDMs and FLMs, is in progress to clarify the implementation of the RSA public-private key algorithm. The amendment was balloted and should have been approved, but the author of the amendment missed his deadlines for addressing comments. Hopefully the red tape will clear soon.
Audio channel labeling advocates had much to be happy about, as the specification 428-12 DCDM Common Audio Channels and Soundfield Group passed ballot, with comments to be resolved. An associated amendment to 429-2 DCP Operational Constraints, the core document for SMPTE DCP, also passed. The documents should now move forward for publication. Seven years ago, this would have been a momentous occasion, as channel labeling was the preferred method for managing audio channel packaging. However, at that time, channel labeling was a contentious issue in SMPTE due to pressures from the broadcast community. The result is that SMPTE DCP implemented format labels instead, as a means to move forward with the standard. With object-based sound now entering the market, there will be little incentive to invest in the R&D needed to implement the new channel labeling standard.
The stereoscopic subtitle standard is moving forward at long last. As the introduction of stereoscopic subtitles requires modification to the core 428-7 Subtitle standard, a review was conducted to undertake improvements in the specification. Numerous issues discovered during ISDCF Plugfests were taken into account, along with the addition of new features for rendering stereoscopic subtitles. The result should be a more robust specification for constructing SMPTE DCP XML subtitles that sidesteps some of the inconsistencies found in testing, as well as providing the industry with a much needed stereoscopic specification for on-screen text. An additional document, 429-12, will also require modification to incorporate the new extension elements needed in the CPL. 429-12 was originally created for the purpose of adding such extensions, but in regards to closed captions and closed subtitles. The modifications to be made will have no impact on the prior work.
Last but not least, the Higher Frame Rate (HFR) Study Group presented its Interim Report. This is a committee-only document that summarizes equipment specifications reported to the SG, as well reports on the many issues related to HFR packaging, distribution, and exhibition. A summary of this report, written by your author, will be published in the September issue of the SMPTE Journal, and will appear on the MKPE.com website shortly after.