Title :
Voice over IP systems with speech bitrate adaptation based on MPEG-4 wideband CELP
Author :
Nomura, Toshiyuki ; Iwadare, Masahiro
Author_Institution :
C&C Media Res. Labs., NEC Corp., Kanagawa, Japan
Abstract :
This paper proposes bitrate adaptation schemes for real-time voice over IP applications, based on multirate and scalable coding capabilities in MPEG-4 CELP. For IP telephony applications, the adaptation scheme based on multi-rate coding is utilized to achieve the best coding quality at a given bitrate. For broadcast applications, the scalable CELP coder produces a layered bitstream and the bitrate control at IP routers determines the number of bitstream layers depending on the network throughputs. Performance evaluation of bitrate adaptation using the MPEG-4 wideband CELP coder is presented
Keywords :
Internet telephony; broadcasting; linear predictive coding; speech coding; voice communication; IP routers; IP telephony; MPEG-4 wideband CELP; bitrate control; broadcast applications; coding quality; layered bitstream; multi-rate coding; multirate scalable coding; network throughput; performance evaluation; real-time voice; scalable CELP coder; speech bitrate adaptation; voice over IP systems; Bandwidth; Bit rate; Internet telephony; MPEG 4 Standard; Narrowband; Scalability; Speech coding; Speech enhancement; Throughput; Wideband;
Conference_Titel :
Speech Coding Proceedings, 1999 IEEE Workshop on
Conference_Location :
Porvoo
Print_ISBN :
0-7803-5651-9
DOI :
10.1109/SCFT.1999.781508
