Title :
New speech processing issues in IP telephony
Author :
Beritelli, F. ; Casale, S. ; Ruggeri, G.
Author_Institution :
Dipartimento di Ingegneria Inf. e delle Telecomun., Catania Univ., Italy
Abstract :
In the field of IP telephony, there are various problems to be dealt with before the QoS currently guaranteed by PSTN networks can be achieved. In this paper, we discuss the main causes of degradation in the quality of conversation in an IP communication scenario. We then point out some new QoS problems involved in speech processing. More specifically, two important aspects of discontinuous transmission are dealt with: the impact of the voice activity detector (VAD) on source throughput and the need for an efficient system of comfort noise. In addition, in a differentiated services (DiffServ) scenario we demonstrate the importance of using a multirate intrastandard codec, together with valid criteria for the reconstruction of lost frames
Keywords :
Internet telephony; quality of service; speech codecs; speech coding; speech intelligibility; voice communication; DiffServ; IP telephony; PSTN networks; QoS problems; coding process; comfort noise; conversation quality degradation; differentiated services scenario; discontinuous transmission; lost frame reconstruction; multirate intrastandard codec; source throughput; speech processing issues; voice activity detector; Codecs; Delay; Diffserv networks; IP networks; Internet telephony; Protocols; Quality of service; Speech processing; Telecommunication traffic; Throughput;
Conference_Titel :
Communication Technology Proceedings, 2000. WCC - ICCT 2000. International Conference on
Conference_Location :
Beijing
Print_ISBN :
0-7803-6394-9
DOI :
10.1109/ICCT.2000.889286
