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ITU-T Study Group 9 (Study Period 2005-2008) |
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Question 1/9 - Transmission of digital television and sound programme signals for contribution, primary distribution and secondary distribution |
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1 Motivation
ITU-T and ITU-R are studying the standards to be used for
digital television and sound programme signals.
Bit-rate reduction processing of such digital signals is widely used both
in studio installations and for direct broadcasting from terrestrial or
satellite transmitters as well as for transmission, including transmission
for contribution and for primary and secondary distribution1.
To facilitate the international exchange of programmes and to
rationalize the design of equipment, it is desirable to continue
to study the methods used for digital source coding of such signals
for all those applications within the scope of Study Group 9.
It is also necessary to ensure the utmost compatibility among the
methods used for the various applications.
The studies include the specification of the availability objectives,
and how availability objectives affect the choice of technical solutions
for, e.g. digital source coding, multiplexing and error protection.
Indeed, the challenge is to find a balanced compromise among the
various factors that interplay in the specification of the transmission
method to be preferred for each application. For instance, a compromise
must be found among
- Required availability of the service,
- Required quality of the picture and sound delivered to the user,
- Total latency of the signal in the transmission chain,
- Differential latency of the audio and video signals (lip-sync) in television transmission
2,
- Recommended bit-rate reduction method and profile,
- Bit rate needed in the channel to deliver the service.
The studies cover not only television and sound programme signals
but also the transport forof
advanced video systems such as 3D, multi-view
and free-viewpoint video over a variety of transport means, including IP-based ones.
It is therefore urgent to study the following Questions, taking into account Recommendations J.80, J.81, J.85, J.86 and J.89, as well as the several existing Recommendations on primary and secondary distribution. (Measurement and control of Quality of Service is covered in Question 2/9)
2 Question
Study items to be considered include, but are not limited to:
- Which source coding methods can be recommended for the transmission of digital television and sound programme signals for purposes of contribution over digital transmission circuits and chains?
- Which source coding methods can be recommended for the transmission of digital television and sound programme signals for purposes of primary and secondary distribution over digital transmission circuits and chains?
- What are the appropriate multiplexing arrangements (component, service, higher level protocols) for the applications above?
- What are the service availability requirements and how do they translate into methods of protection against digital transmission errors for those applications?
- Which
tolerances
requirements must be imposed
on the various parameters that interplay to determine the performance of the transmission service, such as QoS, picture and sound quality, signal latency, etc, in order to ensure
that the transmission service provides adequate
satisfactory performance for those applications
using a reasonable amount of resources, such as a reasonable amount of bit-rate?
- Which provisions can be made to preserve lip-sync when the audio and video components of a television program undergo different delays through the transmission chain?
- For the specific case of MATV, SMATV, MMDS and LMDS networks, what are the distribution configurations appropriate for each system, and their respective operating characteristics?
- What are the appropriate transmission methods for uncompressed digital television and sound programme signals
when they are used for contribution purposes?
W
that are the appropriate transmission methods for 3D, multi-view and free-viewpoint video signals
using different transport means?
3 Tasks
Tasks include, but are not limited to the preparation of a
number of new draft Recommendations by the end of the Study Period year 2012, depending on the contributions that will be received, and on progress in the work of the appointed Rapporteur(s).
An up-to-date status of work under this Question is contained in the
SG 9 Work Programme
(http://www.itu.int/itudoc/itu-t/com9/workprog/)
4 Relationships
Cooperation with ITU-R Study Group 6 and ITU-T Study Groups 13, 15 and 16 is
desirableneeded in the study of this Question.
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