Inter-process metadata communication

Just about every workflow and process in broadcasting today use some form of metadata as the means to linking processes. Numerous processes must be perfectly coordinated with consistent metadata to book, track and air content. Timely information about the program must also accompany the broadcast.

Broadcasters' primary revenue source is the selling of ad space. Numerous processes must coalesce to get the job done. The spot has to get to the broadcaster. It must be cataloged, checked and assigned an identification number. It also must meet technical, time and editorial requirements.

(For years, the advertising industry and many broadcasters have used an ISCI number for commercial identification. The ISCI numbering system is now in the process of being upgrading to an Ad-ID, a 12-digit coding system under the auspices of the Association of National Advertisers.)

With most modern facilities using some form of automated play-to-air capability, information about the content (metadata) must be entered into a traffic system and into a playlist. After the spot finally gets to air, an as-run list verifies that it did air and an air check recording vouches for the quality.

Sophisticated organization-specific workflows and processes have evolved to help this process work properly. These are long-standing processes that the organization has confidence in and are generally reluctant to alter.

First steps
The inclusion of Program and System Information Protocol (PSIP) data in a DTV transport stream is a tedious metadata-intensive process required by the FCC. PSIP (A/65), among other things, delivers in the transport stream the information necessary to assemble a program and populate an Electronic Program Guide (EPG). The EPG process must dynamically update information that can sometimes change close to airtime.

Recognizing the need for automating the PSIP generation process, an ATSC working group was founded by the current chairman Art Allison, Chris Lennon and Fred Grenier to investigate methods to coordinate metadata across PSIP generation systems. The Programming Metadata Communication Protocol Standard (PMCP A/76) is the result of this working group’s efforts.

PMCP defines a method, based on XML message documents, for communicating metadata used by PSIP generation systems. The A/76 document defines the PMCP XML Schema. This metadata can also be entered in the transport stream.

PMCP messages use a “wrapper” approach and include Channel, Show, PsipEvent, Ratings and Transport Stream information. In this way, both current and future programming information is sent to an EPG.

Delivering the goods
Metadata used in PMCP for PSIP generation is also used by traffic and automation systems. Work in this area is beyond the scope of the ATSC and falls into the SMPTE’s production standards domain.

The transition to digital infrastructures is rapidly moving from hand delivery to electronic transfer of commercial spots and content over high performance networks. Pathfire, DG Systems and Vyvx offer complete commercial spot and content delivery solutions. Intra-facility movement of content can be accomplished by applications offered by companies such as Telestream.

Because systems used in this task often work independent of each other, manual processes link the information among system, frequently with the same information being entered repeatedly. Because of the lack of automated communication, the workflow is time-consuming and error prone.

One language
Clearly, standardization of the entire delivery and automation process would be in the best interests of all broadcasters. Yet, many manufacturers hold on to a proprietary business model. This locks broadcasters into a single vendor’s solution and can result in an infrastructure that has converted to digital technology but still uses an analog-based workflow.

There is hope. SMPTE S22-10 Working Group is addressing this conundrum. Its mission is to establish interoperability among the programming, ad sales, traffic, automation and content delivery systems, all of which play a role getting commercials and content into the facility and to air.

Talk to me
The key to tracking the content through the workflow is a unique identifier. A tiered ID structure is used where primary, secondary and local IDs can be consolidated into one ID form. A PMCP XML schema facilitates these three levels of content ID and allows broadcasters to use different IDs to reference the same content by various systems in the workflow.

Two transport mechanisms implement the S22-10 protocol. They are file-based or connection-based. File-based transport is used when large amounts of data transfers do not require critical timing and successful transfer acknowledgement. There is a common file-naming scheme and receiver notification via common folder drop technique that is used.

Connection-based transport uses TCP/IP protocol, with a defined port number. Receiving devices act as servers while sending devices are clients. Clients initiate socket connection and data exchange.

A standard language for Web services messages, Simple Object Access Protocol (SOAP) is used over HTTP (hypertext transfer protocol) as the interface protocol between systems. SOAP servers advertise themselves as objects in Internet registries and use an API.

Security is a major concern. After all, any successful attack to this system hits broadcasters in their breadbaskets. Secure sockets layer (SSL) or transport layer security (TLS) are recommended. This will help insure secure, encrypted communication. A new SMPTE AHG (ad hoc group) has been formed to address and resolve security issues.

Perfect harmony
SMPTE and ATSC working group members have made a conscious effort to ensure these two standards compliment each other. The groups interact and are evolving concurrently. PCMP preceded S22-10. 22-10 wanted to use an XML tool with a higher degree of abstraction and module independence in related work. Because PCMP was open and being updated to V3.0 to support ACAP data broadcasting, modularization of the XML code was also included. (Note: PMCP V3.0 is now in the process of ATSC formal adoption.)

The modularization of PMCP allows using XML “include” directives, similar to the technique used in C coding. In this way, PMCP modules point to schemas that can be used in S22-10 standards. Additionally, ATSC data transport methods are similar to the S-22 file-based and connection-based methods also facilitating interoperability by systems using the standards.

The work continues
The SMPTE BDX WG has over 120 members from more than 70 organizations. Both Chris Lennon, chairman, and Jamie Meyer presented papers in New York at SMPTE last November. Lennon’s paper, “Schedule metadata flow, the times they are a changin’” discussed issues such as open standards, interactivity and using XML. Examples of messaging for ad content and syndication were presented by Meyer in his paper entitled, “Shared metadata in the broadcast environment.”

Work has begun on Engineering Guideline and Recommended Practice documents. A Standard document is also in progress. For those interested in joining the Working Group, SMPTE membership is required. To join SMPTE and the BDX WG, visit

S22-10 would like to verify that is has addressed and met user requirements. The working group is seeking input from users of automation, content delivery and traffic systems to help confirm the work of the Data Exchange Group. If interested in participating to this effort, you may contact Chairman Chris Lennon.

Success in this effort ultimately depends on implementation of PMCP and S22-10 methodologies by equipment vendors. Rather than maintain the proprietary past in new equipment designs and squeeze every penny out of every sale, manufacturers can take the enlightened approach, use open standard interoperable communication protocols and profit form economies of scale. If a system works with all other systems, the customer base has been significantly increased. To this end, Harris, Sundance and VCI have done “precursor” implementations.

The benefits that will come from the ATSC PMCP and SMPTE S22-10 Working Groups efforts include a reduction of redundant tasks, less human intervention and dynamic scheduling updates.

Additional reading
Simple Object Access Protocol (SOAP)

Hypertext Transfer Protocol (HTTP)

Extensible Markup Language (XML)