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The ANSI Standard for Video Codecs

 

A Scenic Wonders Executive White Paper
by Matt Peterson

 

Standards are critical to the growth of all industries because they enable rapid product innovation, widespread equipment deployment and the growth of new applications. This paper describes the current standards for video codecs for production and postproduction executives.

Benefits of Standards

By allowing the interoperation of equipment and services, standards deliver the advantages of a truly competitive marketplace.

  • Standards give buyers and users a choice of compatible equipment that they can evaluate on a comparable basis. Vendors compete on quality, reliability, service and price instead of on conflicting proprietary technologies.

  • Previous purchases do not lock in future buying decisions. Users can mix and match equipment from different vendors as requirements change and products evolve.

  • Standards encourage new manufacturers to enter the market to meet new requirements or to address needs unfulfilled by established suppliers.

  • Standards motivate established product manufacturers to continually improve both products and prices to hold their customers. They cannot lock customers into proprietary technology in the presence of strong standards.

  • Collaborative systems become more likely if the players have flexibility deploying equipment under the umbrella of standards. Systems that require specific product purchases and exact configuration settings are cumbersome and unsatisfying. Standards- based systems allow all collaborators to quickly achieve full productivity.

 

Networks for Collaborative Production & Postproduction

Standards are emerging for all facets of the content creation industry, but it is in connectivity applications that the value of standards is most immediate.

Connectivity is critical to the content creation industry. Each production necessitates the creation of a virtual community of players who need to respond quickly to each other's needs. The advantages of quickly distributing and interactively processing video content have given rise to a host of products and services for video connectivity.

DS-3 telecommunication circuits form the backbone of major video service networks throughout North America. The "lines", usually carried by fiber, have a bandwidth of 45 Megabits per second (Mbps). The critical hardware component of these networks is the codec (coder/decoder) that processes the video and handles the compression and decompression necessary to transport video over a 45 Mbps circuit. All facility equipment must connect to this codec to send or receive audio and video signals.

Video Standards

Facilities creating video for national and international audiences have adopted component digital video production as their internal standard. The serial digital interface (SDI) and the serial component digital video format (ITU-R 601-2) are specified by standards bodies. They deliver all the advantages of standards-based technologies and their rapid proliferation through the industry is a natural consequence.

The industry's response to this standard was so strong that this component digital video format is now popularly known by its standards designation of "601". This paper will continue that reference.

The next logical step was to develop a standardized way to connect facilities collaborating on 601 productions. Unfortunately, early DS-3 video networks utilized codecs based on other video formats and/or proprietary coding schemes.

European Standard

Europeans were first to respond to the situation with a codec standard. The European Telecommunications Standards Institute (ETSI) adopted a standard for video codecs in 1992: ETS 300 174. The ETSI activity standardized several items that are key to collaborative postproduction.

  • Direct input of 601 video preserves the highest quality possible during the transmission process.

  • A standard, published coding algorithm (DCT) for the video ensures codec compatibility.

  • Conditional access through scrambling ensures the security of intellectual property on local, national and international networks.

  • Timecode transmission enables true collaborative editing and other postproduction activities.
The standardization of a video coding scheme was particularly important. Proprietary coding had meant that each collaborator in each product had to have exactly the same codec at their facility. Once the local telecommunications company committed to a particular codec, collaboration with facilities outside that service area was difficult, if not impossible. This was an untenable situation within the increasingly integrated European media community. The ETSI standard was greeted as a long overdue solution.

American Standard

The situation in North America was no better. Each local telephone company and each long distance carrier used different and incompatible codecs. Even the same model units from the same manufacturer were incompatible if not identically configured. The situation was inhibiting the growth of collaborative production and postproduction at a time when the content industry was enjoying unprecedented growth.

In late 1995, the American National Standards Institute (ANSI) adopted a standard for 45 Mbps video codecs and formally published the standard in 1996. The standard is designated "ANSI T1.802.01-1996."

The ANSI standard takes the key elements of the ETSI standards and adapts them for use in North America. For example, the multiplexing of compressed video, audio and ancillary information is modified to support the 45 Mbps bandwidth of the DS-3 service standard in North America. The comparable European standard is 34 Mbps.

The ANSI standard also extends the ETSI standard in two important ways:

  • Support of remote machine control enables a real-time link between equipment during a collaborative session.
  • Four channels of AES/EBU digital audio (two stereo pairs) maintains the separation of dialog and M&E tracks.
Finally, ANSI tied every possible element of the codec standard to existing standards from SMPTE and ANSI to ensure compatibility with existing equipment and operations.

Benefits of the ANSI Standard

The new generation of video codecs built to the ANSI standard has the potential to greatly expand the possibilities for collaborative production and postproduction throughout North America. The benefits of the new equipment are substantial.

  • The ANSI standard specifies a mature and proven compression algorithm, DCT, that is well accepted in the video industry. This eliminates the confusion and incompatibility caused by proprietary coding schemes.
  • System-wide use of industry standard equipment avoids the undesirable effects of repeated compression cycles due to the signal conversion previously required between incompatible equipment.
  • An open market motivates both new and established codec manufacturers to continually improve products and services for the industry.
  • The standard covers all the elements essential to collaborative postproduction - 601 video, digital audio, timecode, machine control and conditional access - to enable productive communication among ever-changing associations of media professionals.
Telephone companies must replace the installed base of legacy codecs before the content creation community can fully realize these benefits across all of North America. A combination of strong demand from the production/postproduction community and leadership from service innovators should overcome any inclination to delay. The need is great, the solution is timely, and the benefits are compelling.

Published by: Scenic Wonders, Inc. 6409 Odana Road, Suite A, Madison, WI 53719, USA
Tel: (608)273-4803 Fax: (608)273-4837

© 1997 Scenic Wonders, Inc.

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