EBU/SMPTE Task Force on Timing and Synchronization Report Published

In late 2007, the Society of Motion Picture and Television Engineers (SMPTE) and the European Broadcasting Union (EBU) formed a Joint Task Force on Timing and Synchronization to investigate a potentially major change in one of the key aspects of the broadcasting infrastructure system timing and synchronization see TV TechCheck of October 1, 2007. The task force, chaired jointly by Dr. Hans Hoffmann of the EBU Technical Department, and Peter Symes, SMPTE Director of Standards & Engineering, included some 170 experts from all sectors of the industry and, after numerous meetings and considerable analysis and discussion on contributions received, published its report last week.

The report notes that existing solutions, principally color black distribution and SMPTE 12M Time-code, both date from analog-only systems and tape recorders. Both solutions are still viable today but there have been major changes in technology and requirements since their development. The Task Force was charged with identifying user requirements for the digital age, and suggesting technologies for standardization that would provide cost-effective solutions.

The report takes the form of a Request for Standardization (RFS), intended as a reference document for the SMPTE technology committee that is expected to develop the recommended standards. It comprises two main sections, on Synchronization and Time-Related Labeling (TRL), which describe the basis of the technologies needed to meet the user requirements and the standardization work required. These are followed by various annexes with information on audio applications, time labels for standards conversion, IEEE 1588 Precision Time Protocol, and contributions from several major manufacturers. The extracts below are taken from the report, with permission from SMPTE.

Introduction
"This document describes the consensus of the joint EBU/SMPTE Task Force on Timing and Synchronization in light of the responses received to its Request for Technology (issued 03/2008). The Task Force requests that the Society of Motion Pictures and Television Engineers (SMPTE) undertake standardization efforts with reference to this document."

Motivation
"The current methods of synchronization for television, audio and other moving picture signals rely on standards that have been in place for over 30 years. These standards are becoming increasingly inappropriate for the digital age with, for example, networked content sharing and the higher frame rates appropriate to HDTV, UHDTV and other image formats. This document is intended to provide a foundation to standardize a new synchronization and time labeling system."

"The Task Force has focused on a conceptual solution first proposed to SMPTE several years ago. Fundamentally, if any periodic signal has its state defined at a given point in time (the 'Epoch') its state can be calculated at any future time, provided the time is known with sufficient accuracy. The problem, therefore becomes one of distributing time to slave devices."

Scope
"The intention of this document is to give guidelines on what the SMPTE is requested to standardize based on the initial user requirements defined by the Task Force in its first report, the 'Request for Technology' (RFT), together with the 'Requests For Standardization' (RFS) presented within this document.

Broadly speaking, the standardization work concerns Time-Related Labeling (TRL) and a new A/V synchronization system. The Task Force suggests that the standardization activities in these fields are continuously reviewed against the user requirements and proposals outlined in this document. Each member of the Task Force who wished to give additional or more specific input to the Task Force work was permitted to add this in an appendix to this document.

The Task Force is well aware that the techniques that are outlined in this document may need reassessing and further in-depth investigation when proof-of-concept and interoperability tests are conducted, for instance. New findings at this stage may therefore impact the standardization activities of SMPTE."

Synchronization
The following diagram is taken from the section describing the synchronization system concept, and illustrates the intention to define a single interface for so-called Common Synchronization Interface (CSI).

Conceptual diagram for the synchronization system

The CSI is an internal interface layer within products using this type of synchronization. It provides a uniform method for designers to connect their implementation to the synchronization system.

The rest of this section describes the requirements, format, mechanism, and scenarios for the synchronization system proposed.

Time-Related Labeling (TRL)
"Originally, the Task Force considered that only a timestamp would be required both for acquisition and for use in post-production. It was eventually realized that a timestamp alone is not sufficient to guarantee unambiguous conversion. To take account of the particular needs for video, it was decided to propose two types of TRL. TRL Type 1 includes only the timestamp, while TRL Type 2 includes a Media Unit (MU) count in conjunction with a Start TRL timestamp. With the correct choice of TRL Type 1 and TRL Type 2 according to the application, conversion from a timestamp to MU number for video production is no longer needed. Special applications such as over/under cranking can be supported in the same way as fixed frame rates."

"The figure shows a typical simple independent audio/video acquisition and postproduction process and illustrates the basic principles of the two types of TRL."

TRL Workflow Example: Independent Audio/Video
acquisition and postproduction

The rest of this section includes detailed information on the components of the TRLs, their representation and use cases, and states that: "standards that describe the representation of the TRL in binary, as XML and as human readable formats are required. The human readable variants need to consider current industry practice to simplify the transition from SMPTE 12M to the TRL."

The full report comprises 115 pages, including appendices, and is recommended for anyone wishing to stay current on developments in this area of television engineering. It is available for purchase for $25 at the SMPTE Booth at the IBC Convention this week and for download from the online SMPTE Store (https://store.smpte.org).

2010 NAB Show Call for Speakers

Call for Technical Papers – NAB Broadcast Engineering Conference

The 2010 NAB Show will host the 64th Broadcast Engineering Conference. This world-class conference addresses the most recent developments in broadcast technology and focuses on the opportunities and challenges that face broadcast engineering professionals. Each year hundreds of broadcast professionals from around the world attend the conference. They include practicing broadcast engineers and technicians, engineering consultants, contract engineers, broadcast equipment manufacturers, distributors, R&D engineers plus anyone specifically interested in the latest broadcast technologies.

Do you have something to share?
If you feel qualified to speak at the NAB Broadcast Engineering Conference, we invite you to submit a technical paper proposal. Not all acceptable submissions can be included in the conference, due to the large number of submissions that are received and the limited number of available time slots.

NAB Broadcast Engineering Conference Committee Meets to Begin Planning for 2010

The NAB Broadcast Engineering Conference (BEC) Committee met at NAB headquarters on September 9 to begin planning for the 2010 NAB Broadcast Engineering Conference. (Pictured left to right front row): Joe Snelson, BEC Committee Chairman, Meredith Broadcasting Group; Jeff Smith, Clear Channel Radio – NYC; Jim Kutzner, PBS; Dom Bordonaro, Cox Radio.; Thomas Hankinson, ABC; (back row); David Folsom, Raycom Media, Inc.; SBE Representative, John Poray; Andy Laird, Journal Broadcast Group; Michael Cooney, Beasley Broadcast Group, Inc. BEC Committee member not pictured is Glenn Reitmeier, NBC Universal and SBE Ennnes representative Fred Baumgartner.

PLAN TO ATTEND!
The IEEE Broadcast Technology Society
59th ANNUAL BROADCAST SYMPOSIUM
14 -16 October 2009
The Westin Alexandria
Alexandria, VA, USA
www.ieee.org/bts/symposium

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