1 Type of Question

Question intended to lead to a Recommendation or a set of Recommendations.

2 Motivation

The use of the Internet for the delivery or exchange of sound programmes or television programmes as multimedia information is spreading at an impressive pace. This is confirmed by the very high rate of increase in the penetration of these Internet services.

The Internet as we know it today is only capable of supporting rather modest bit rates; these generally are only adequate for the delivery of sound programmes or television programmes of modest sound/picture quality and timeliness; they consequently may fail to meet the expectations of an audience accustomed to the programme quality provided by the CD and by broadcast/cablecast television.

However the speed capability of the Internet is steadily increasing as the bit-rate capability of networks improves; this leads to the expectation that technology may reach a stage in the near-to-medium future when the delivery of sound programmes and television programmes of "entertainment" quality may become viable.

Nevertheless, the functional peculiarities of Internet services are such, that more stringent limitations on the available bit rate-per-programme will very likely continue to apply in the medium future, than it is the case for digital broadcasting or cablecasting. One can thus expect that a carefully-considered choice among the tools offered for use with the Internet will need to be made, in order optimally to fit the specific requirements of webcasting.

For instance, the MPEG-2 tool-kit used for digital broadcasting/cablecasting may likely be used for webcasting also, however a somewhat different set of tools may well need to be selected in the tool-kit, than the one adopted for broadcasting and cablecasting, in order to find a compromise between sound/picture quality and available bit rate-per-programme, that is optimized to the specific case of webcasting.

As another example, since ATM is used for the Internet, ways may need to be identified to obviate the well-known problems caused by ATM in the synchronized and timely delivery of multimedia messages, in order that webcasting may emulate broadcasting and cablecasting in these aspects also.

A study of these and of the other problems related to the use of the Internet for webcasting is quite urgent, since we are already witnessing experiments in the distribution or exchange of sound programmes and of television programmes on the Internet, and any delay in the ITU-T action may result in the entrenching of de facto operating standards that might be less than optimal ones for such services, or that may fail to attain the required widespread acceptance.

3 Questions

• What are the service requirements applicable to the interactive delivery ("webcasting") of sound programmes and of television programmes to the public over the Internet, in terms of sound quality, picture quality, quality of the other components of the programme, synchronization of the various programme components, timeliness, reliability of delivery, etc.?
• Which sound and picture source coding methods can be recommended for this kind of delivery of sound programmes and of television programmes?
• Which protocols (component, service, higher protocols) can be recommended?
• Which measures can be recommended to ensure synchronized and timely reception of the various components of the programme at the destination point?
• What is the required Quality of Service and how does it translate into possibly enhanced methods for protection against transmission errors?
• Which conditional access methods can be recommended when conditional access is implemented in webcasting?

4 Expected results and anticipated target dates

It is expected that this Question will result in further draft Recommendations by 2002.

5 Relationships

Cooperation with ITU-T Study Groups 13, 15 and 16, and with ITU-R Study Group 6 is needed in the study of this Question. Communication is also to be ensured with IETF through ITU-T Study Group 13.