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
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.
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
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
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.
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
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
- 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 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
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
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
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.
- 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.
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.
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
- 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
- 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
- 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.
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.