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1 Type of Question
Task-oriented Question that should eventually result in a set
of Recommendations.
2 Motivation
ITU-T has adopted several Recommendations for the
transmission of digital television signals for contribution,
primary distribution and secondary distribution applications.
However, a number of issues related to the measurement,
monitoring and control of digital and mixed analogue-digital
television transmission chains still remain to be solved.
- ITU-R has recommended methods for the subjective
assessment of picture quality (see Recommendation BT.500-8).
There is a need to confirm that those subjective assessment
methods are equally applicable to the case of television
transmission on digital or mixed analogue-digital chains.
- In the digital domain, ITU-R SG 6 and ITU-T SG 12 and
SG 9 are also studying together, in a Video Quality Experts
Group, the identification of appropriate parameters and
algorithms that are representative of digital picture
quality, as well as the correlation of the objective
measurement of those parameters to the subjective picture
quality.
- Concerning the measurement of the overall Quality of
Service (QoS), in the analogue world there is a direct
relationship between network impairments and the QoS of
television transmission. This is not the case for digital
transmission networks. Furthermore, there is a need to
identify the group of parameters that can provide objective
measurement of the overall QoS and continuous in-service
monitoring and control of it along the transmission chain
for digital and for mixed analogue-digital television
transmission.
3 Questions
- Are the methods recommended or studied by ITU-R Study
Group 6 for subjective assessment of digital picture quality
also applicable to the area of activity of Study
Group 9?
- If not, should any different or additional methods
for picture quality assessment be recommended by Study Group
9, as specifically applicable to impairments introduced by
digital or mixed analogue-digital television transmission
chains?
- How should the methods developed by ITU-R SG 6,
or extended by SG 9, for subjective assessment be
applied to digital or mixed analogue-digital transmission
chains?
- Which parameters and algorithms are representative of
digital picture quality and how does the objective
measurement of them correlate to subjective picture quality?
(This work is to be carried out within the Video Quality
Experts Group.)
- How should the objective measurement of impairments
introduced by digital or mixed analogue-digital transmission
networks be carried out?
- Which network parameters should be used to provide
objective measurement of the overall QoS and should be the
basis for continuous in-service monitoring along the
transmission chain both for digital and for mixed
analogue-digital television transmission?
- Which network parameters can be dynamically adjusted
for the supervision and control of the overall QoS in
digital television transmission networks and how can such
supervision and control be implemented in operation?
4 Expected results and anticipated target dates
A first draft Recommendation should be ready before the end
of 2002. Others will be ready before the end of 2003.
5 Relationships
Liaison should be established with ITU-T Study Groups 12, 13,
15 and 16 and with ITU-R SG 6.
Part of the work will be performed in collaboration with the
Video Quality Experts Group.
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