(Continuation of part of Question 20/16)

Background and justification

Currently, there is an increased interest for a high-quality wideband speech coder operating at bit rates around 16 kbit/s for wireless and packed-based applications (including IP). This question will aim at developing a suitable, high-quality algorithm for the following applications:

• Wideband transmission over the Internet.
• IP videoconferencing.
• Third generation wireless systems.
• Audio-conferencing for business applications.
• ISDN wideband telephony.
• ISDN videotelephony and videoconferencing.

The following general guidelines are considered relevant for this wideband activity:

• Input and output audio signals should have a bandwidth of 7 kHz at a sampling rate of 16 kHz.
• Speech is the primary signal of interest.
• Robustness to frame erasures and random bit errors is important.
• Low algorithmic delay.
• Interoperability with systems using different coding methods.

Study items

a) Consideration of system requirements and constraints (e.g. influence of H.32x protocols, interoperability with systems using different coding methods, tandeming in MCU configurations).

b) The study of appropriate environmental conditions (e.g. error conditions, background noise conditions) for the primary targetted applications.

c) Study of scaleable coding techniques. A scaleable codec may, for example, consist of one or more of the following features: variable bit rate, variable bandwidth, variable decoding complexity, variable delay, embedded bit stream. The scalability is targeted for a wide set of applications while maintaining high quality.

d) Study of the applicability of voice activity detection and comfort noise generation techniques.

e) Definition of test conditions and evaluation procedures to be applied in selecting between candidate algorithms on the basis of subjective voice performance and non-voice performance.

f) Selection and specification of one or several coding schemes.

g) Definition of procedures to be used in verifying the implementation of algorithms.

h) Study of the support of text-telephony (TDD) devices in systems using wideband speech and audio coding.

Specific tasks

• Study and definition of performance and test requirements for the new coding algorithm: 2000.
• Evaluation of algorithm performance against specified requirements for the new coding algorithm: early 2001.
• Definition of algorithms and associated verification procedures for the new coding algorithm: end 2001.

Relationships

• Other relevant Questions of SG 16.
• ITU-T SG 11 and ITU-R SG 8 (mobility aspects).
• ITU-T SG 12 (evaluation of performance with respect to voice quality).
• ISO/MPEG (standardization of similar types of coding algorithms).
• 3GPP and 3GPP-2.
• IETF (for packetization issues).
• ITU-T SG 13 (for IP aspects).