Change search
ReferencesLink to record
Permanent link

Direct link
Sicsophone: A Low-Delay Internet Telephony Tool
Number of Authors: 3
2002 (English)Report (Refereed)
Abstract [en]

The end to end delay is a critical factor in the perceived quality of service for Voice over IP applications. The described solution is a complete system-level platform and complements QoS work in the network and application areas. We describe a VoIP system that couples the low level features of audio hardware with a jitter buffer playout algorithm. Using the sound card directly eliminates intermediate buffering as well as providing fine control over timers needed by a soft real-time application such as VoIP. A statistical based approach for inserting packets into audio buffers is used in conjunction with a scheme for inhibiting unnecessary fluctuations in the system. We give comparisons for the performance of the playout algorithm against idealised playout conditions. We also present mouth to ear delay measurements for selected VoIP applications and show that several hundreds of milliseconds can be saved by using the techniques described in this paper. A prototype for both UNIX and Windows platforms (NT and 9X) has been implemented, demonstrating that our system adapts to network conditions whilst maintaining low delays.

Place, publisher, year, edition, pages
Swedish Institute of Computer Science , 2002, 1. , 15 p.
SICS Technical Report, ISSN 1100-3154 ; 2002:26
Keyword [en]
Low Delay, VoIP, buffer playout
National Category
Computer and Information Science
URN: urn:nbn:se:ri:diva-22004OAI: diva2:1041546
Available from: 2016-10-31 Created: 2016-10-31

Open Access in DiVA

fulltext(175 kB)10 downloads
File information
File name FULLTEXT01.pdfFile size 175 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Computer and Information Science

Search outside of DiVA

GoogleGoogle Scholar
Total: 10 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 5 hits
ReferencesLink to record
Permanent link

Direct link