|(Continuation of Question 18/12) |
In today's society, audio and audio-visual telemeetings and audio- and video-conferences are gaining in importance. The term telemeeting is used here to cover with one term all means of audio or audio-visual communication between distant locations. The term also emphasizes that a telemeeting is considered to be more flexible and interactive than a traditional business audio- or video-conference. Telemeetings are more and more common also in private usage scenarios, e.g. when families communicate over large distances.
If the perceived quality is good enough, such telemeetings can be used as a complement to face-to-face meetings, and travel time and cost can be reduced. In spite of the increased use of telemeeting systems, there is currently no standardized method to evaluate the quality of experience (QoE) of a telemeeting. Hence, there is a need to develop an agreed way of quantifying the quality of experience of multi-party services that are conversational and interactive.
Telephony has traditionally been a point-to-point service, but a telemeeting is often a multipoint communication, where the participants can use different types of equipment to connect to the (virtual or real) meeting space, e.g. by fixed phone, mobile phone, PC, videoconferencing or telepresence equipment. To obtain a good evaluation of the telemeeting quality of experience, the quality perceived by all participants in a telemeeting needs to be assessed.
There are standardized subjective and objective test methods for several components in a telemeeting, such as speech, audio and video codecs, characterized by bit rate (fixed or variable), frame rate, resolution, noise cancellation, background noise, and synchronization and transmission impairments. Some recommendations on how to assess the interaction between these factors are available, too. In a telemeeting context, however, these factors need to be assessed in the light of multiple users connected via possibly asymmetric links. The main focus from the start is on subjective assessment strategies. The results from performed tests can then form a base for objective quality assessment of telemeetings and can provide insights on quality aspects for telemeeting services.
The following Recommendations/Supplements, in force at the time of approval of this Question, fall under its responsibility:
Study items to be considered include, but are not limited to:
How can the quality of experience of multiparty audio and audiovisual telemeetings be evaluated?
What performance criteria play a role when it comes to the assessment of audiovisual telemeetings?
What is the quality impact of the different ways of connecting to a telemeeting?
What is the quality impact of multiple users connected to the telemeeting from one single-location, from multiple locations or via links of highly different quality?
What aspects of communication performance need to be addressed when it comes to multiparty interaction across links with delay or limited resources for audio and video?
How can different quality aspects related to telemeeting quality be quantified, and how can their relative importance for the whole telemeeting quality be assessed with standardized subjective and objective evaluation methods?
How do telemeeting assessment methods scale with the number of participants?
Which additional performance criteria need to be assessed, especially when it comes to business meetings in a group-collaboration context?
How can spatial sound and video be evaluated in a telemeeting (via headphone- or loudspeaker reproduction, with problems such as the microphone placement, echo-cancellation, camera adjustment, lighting conditions, etc.)?
What are the relative roles of the transmission, the conference bridge or server, and the terminal equipment being employed on quality perception, also with regard to the user experience of the service?
What is the additional impact of data media such as presentation slides on user perception?
Tasks include, but are not limited to:
Recommendation on how to subjectively quantify the quality of audio and audiovisual multiparty telemeetings, where the participants can have different types of connections to the meeting.
Recommendation on how different delays for different participants affect the meeting quality. Suitable test tasks for evaluation methods of interactive multiparty audio and audiovisual telemeetings are needed.
Recommendation on subjective method for simulated conversation tests addressing audio and audiovisual call quality.
Recommendation on how to evaluate the perceived quality of meetings using spatial audio. The methods should be applicable to listening through both headphones and loudspeakers.
Recommendation on the use of auditory and visual cues for high-quality telemeetings in different application contexts such as business and private meetings (including, for example, aspects such as eye-contact and other visual cues, e.g. in the light of technical characteristics such as screen sizes).
Recommendation on the quality aspects and implications for telemeeting services of different quality.
Recommendation on how the quality impact of separate components in a telemeeting that have been tested separately can be weighted together to give an overall telemeeting quality value.
An up-to-date status of work under this Question is contained in the SG 12 work programme http://www.itu.int/ITU-T/workprog/wp_search.aspx?q=10/12
5/12, 6/12, 7/12, 8/12, 9/12, 13/12, 14/12, 15/12
ISO-MPEG, 3GPP, 3GPP2, IETF, ETSI
VQEG, IMTC Telepresence AG, IMTC SIP Parity AG, IMTC IMS AG, ATIS PRQC