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1 Type of Question
Studies performed in the framework of this Question should result in Recommendations.
2 Motivation
High quality demands for the production of programme material
and particularly the demand for the lowest possible latency in
interactive applications, or for networked production lead to a
requirement for the uncompressed transmission of video and audio
signals via telecommunication networks. Therefore systems and
mechanisms for the direct mapping of 270 Mbit/s DSC (Digital
Serial Components) signals on DWDM (Dense Wavelength Division
Multiplex) systems, on ATM-based networks and on SDH/SONET based
networks are being developed. In order to avoid interoperability
problems, standards for mapping procedures and signal quality
should be studied in due course.
In the audio domain, mapping devices for uncompressed AES/EBU
audio studio signals onto ATM are already available and
standards to solve interoperability problems are also urgently
needed in this area.
Interfaces for the DSC signal and for digital audio are
defined in Recommendations ITU-R BT.656-4 and ITU-R BS.647-2,
respectively.
Direct mapping of these signals onto the transport network
would allow the transport of all additional signals, such as
embedded audio in DSC and ancillary signals, as they are
specified within the mentioned Recommendations without the need
for any special adaptation.
In addition to uncompressed video, signals such as SDTI
(Serial Data Transport Interface) and ASI (Asynchronous Serial
Interface) could be carried via these network adapters.
3 Questions
Mapping onto DWDM systems
- What are the means to ensure stable operation of
optical network equipment transmitting serial DSC signals
which may contain long sequences of identical bits
(pathological signals being the worst case)?
- What are the operational conditions for optical
transmission systems when fed with the DSC signals which have
different spectral characteristics from SDH/SONET signals?
- What is the influence of network characteristics on the
end-to-end quality parameters of the studio signals and what
are the means to maintain the quality parameters within
specified limits?
Mapping onto ATM-based networks
- What are the mechanisms to map/demap the DSC signals
on/from ATM cells?
- What are the methods to protect the studio signals
against transmission errors?
- What are the means to maintain the quality parameters
within specified limits?
Mapping onto SDH/SONET networks
- What are the mechanisms to map/demap the DSC signals
on/from SDH octets?
- What are the mechanisms to map the DSC signal onto SDH/SONET
hierarchical levels?
- What are the methods to protect the studio signals
against transmission errors?
- What are the means to maintain the quality parameters
within specified limits?
4 Expected results and anticipated target dates
It is expected that this Question will result in the
preparation of new Recommendations by the end of 2002.
5 Relationships
Liaison should be established with ITU-T SG 15, SG 13
and ITU-R SG 6 in the study of this Question.
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