Motivation

A major challenge for emerging IP-based networks is to provide adequate Quality of Experience (QoE) and Quality of Service (QoS) for new multimedia services and applications. As an example, IPTV is a rapidly emerging new multimedia service.

The telecommunications industry is working to adopt more flexible infrastructure to control costs and facilitate the introduction of new services. Examples are next generation IP networks (NGN) and 3G mobile networks – both of which exhibit time-varying performance. Measures that predict user-experience are useful in monitoring and managing time-varying performance and help to facilitate the rollout, efficient operation and effective service management of such networks.

The industry is already benefiting from ITU-T recommendations for objective video quality assessment. Most of the techniques described in these recommendations are signal based. Signal processing technology can be used to estimate the contribution of a number of factors affecting the transmission performance of the complete connection. An example of such recommendation is J.144.

The accuracy of such methods (measured by their correlation with the subjective opinion) is high, but this requires a quantity of memory and processing power that does not allow their application in all situations.

As far as packetized systems (and more generally, non linear systems) are concerned, they are currently not covered by ITU-T Recommendations, though there is some important needs in the industry for such methods. The work on the development of parametric models that do not access to the video or audio content of multimedia or audiovisual stream started during last study period under Q.14/12 with the provisional names P.NAMS (access to basic protocolar information) and P.NBAMS (similar + access and analysis of information from the bit-stream). The idea is to adopt a similar approach than the one in P.564 for performance requirements for models assessing voice transmission quality from protocol analysis information in IP networks4.

The following major Recommendations, in force at the time of approval of this Question, fall under its responsibility:

P.56, P.561, P.562, P.564

Question

Study items to be considered include, but are not limited to:

• How can non-intrusive measurements at the IP layers be implemented and improved, for instance by taking into account new services (video-telephony, multimedia streaming) or protocols or transmission layers (e.g. RTCP XR, MPEG 2)?
• What relationship exists between the subjective responses of users at the terminals and the objective measurements made from the point at which the non-intrusive assessment system is connected?
• What measures give an estimate of the transmission quality of a connection including the accumulated effects of all technologies (e.g. IP, radio, ATM, etc.)?
• How can such measures be used to assess, plan and maintain the transmission quality of networks?
• Define the scope of P.NAMS and P.NBAMS
• Review existing methods and models, and identify missing components
• Define inputs and outputs of P.NAMS and P.NBAMS
• Identification of relevant subjective test methodologies (in co-operation with VQEG)
• Identification of existing subjective test data
• Collection of new subjective test data
• Development of new Recommendations P.NAMS and P.NAMS
• Ensure consistency with development of hybrid models by VQEG
• Considerations on how to help measure and mitigate climate change

Tasks

Tasks include, but are not limited to:

• New Recommendation on non-intrusive evaluation model of multimedia quality based on IP protocol information (P.NAMS)
• New Recommendation on non-intrusive evaluation model of multimedia quality based on IP protocol and bit-stream information (P.NBAMS)
• New Recommendation(s) on guidance for the use of P.NAMS and P.NBAMS in operational contexts.

An up-to-date status of work under this Question is contained in the SG 12 Work Programme http://1f8a81b9b0707b63-19211.webchannel-proxy.scarabresearch.com/ITU-T/workprog/wp_search.aspx?isn_sp=545&isn_sg=551

Relationships

Recommendations: P.564, G.1000-series, J series recommendations on video quality

Questions: 13/12

Study groups: ITU-T SG 9, SG 13, SG 16

Standardization bodies: ETSI (STQ, TISPAN), IETF (IPPM, AVT), ATIS (IIF).

Other groups: VQEG, HGI, DSL Forum