Multimedia Tools and Applications

, Volume 14, Issue 1, pp 23–53 | Cite as

Design and Experimental Evaluation of an Adaptive Playout Delay Control Mechanism for Packetized Audio for Use over the Internet

  • Marco Roccetti
  • Vittorio Ghini
  • Giovanni Pau
  • Paola Salomoni
  • Maria Elena Bonfigli


We describe the design and the experimental evaluation of a playout delay control mechanism we have developed in order to support unicast, voice-based audio communications over the Internet. The proposed mechanism was designed to dynamically adjust the talkspurt playout delays to the traffic conditions of the underlying network without assuming either the existence of an external mechanism for maintaining an accurate clock synchronization between the sender and the receiver during the audio communication, or a specific distribution of the audio packet transmission delays. Performance figures derived from several experiments are reported that illustrate the adequacy of the proposed mechanism in dynamically adjusting the audio packet playout delay to the network traffic conditions while maintaining a small percentage of packet loss.

multimedia applications packetized audio playout delay control packet loss Internet 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    M. Bernardo, R. Gorrieri, and M. Roccetti, “Formal performance modeling and evaluation of an adaptive mechanism for packetized audio over the internet,” Formal Aspects of Computing, to appear.Google Scholar
  2. 2.
    J. Bolot, H. Crepin, and A. Vega Garcia, “Analysis of audio packet loss on the internet,” in Proc. of Network and Operating System Support for Digital Audio and Video, Durham (NC), 1995, pp. 163–174.Google Scholar
  3. 3.
    D. Cohen, “Issues in transnet packetized voice communications,” in Proc. of Fifth Data Communication Symposium, Snowbird (UT), 1977, pp. 6.10–6.13.Google Scholar
  4. 4.
    F. Cristian, “Probabilistic clock synchronization,” Distributed Computing' Vol. 3, pp. 146–158, 1989.Google Scholar
  5. 5.
    V. Hardman, M.A. Sasse, and I. Kouvelas, “Successful multi-party audio communication over the Internet,” in Communications of the ACM Vol. 41, pp. 74–80, 1998.Google Scholar
  6. 6.
    ITU-T Recommendation G.729, “Coding of speech at 8-kb/s using coniugate-structure algebraic-code-excited linear-prediction,” 1996.Google Scholar
  7. 7.
    ITU-T Recommendation G.723.1, “Dual rate speech coder for multimedia communications transmitting at 5.3/6.3-kb/s,” 1996.Google Scholar
  8. 8.
    V. Jacobson and S. McCanne, vat, Scholar
  9. 9.
    T.J. Kostas, M.S. Borella, I. Sidhu, G.M. Schuster, J. Grabiec, and J. Mahler, “Real-time voice over packetswitched networks,” IEEE Network, Vol. 12, pp. 18–27, 1998.Google Scholar
  10. 10.
    W.E. Leland, M.S. Taqqu, W. Willinger, and D.V. Wilson, “On the Self-Similar Nature of Ethernet Traffic,” in IEEE/ACM Trans. on Networking Vol. 2, pp. 1–15, 1994.Google Scholar
  11. 11.
    M. Macedonia and D. Brutzmann, “mbone provides audio and video across the Internet,” in IEEE Computer Magazine, Vol. 21, pp. 30–35, 1994.Google Scholar
  12. 12.
    D.L. Mills, “Improved algorithms for synchronizing computer network clocks,” in Proc. of ACM SIGCOMM’ 94, London (UK), 1994, pp. 317–327.Google Scholar
  13. 13.
    S.B. Moon, J. Kurose, and D. Towsley, “Packet audio playout delay adjustment: Performance bounds and algorithms,” in ACM Multimedia Systems Vol. 6, pp. 17–28, 1998.Google Scholar
  14. 14.
    R. Ramjee, J. Kurose, D. Towsley, and H. Schulzrinne, “Adaptive playout mechanisms for packetized audio applications in wide-area networks,” in Proc. of IEEE INFOCOM'94, Montreal (CA), 1994.Google Scholar
  15. 15.
    P.V. Rangan, S.S. Kumar, and S. Rajan, “Continuity and synchronization in MPEG,” in IEEE Journal on Selected Areas in Communications, Vol. 14, pp. 52–60, 1996.Google Scholar
  16. 16.
    M. Roccetti, M. Bernardo, and R. Gorrieri, “Packetized audio for industrial applications: A simulation study,” in Proc. of 10th European Simulation Symposium, Nottingham (UK), 1988, pp. 495–500.Google Scholar
  17. 17.
    M. Roccetti, V. Ghini, G. Pau, P. Salomoni, and M.E. Bonfigli, “Design and experimental evaluation of an Adaptive playout delay control mechanism for packetized audio for use over the Internet,” UBLCS Technical Report n. 98-4, Laboratory for Computer Science, University of Bologna, May 1998.Google Scholar
  18. 18.
    H. Schulzrinne, “Voice communication across the Internet: A network voice terminal,” Tech. Rep., Dept. of ECE and CS, Univ. of Massachusetts, Amherst (MA), 1992.Google Scholar
  19. 19.
    H. Schulzrinne, S. Casner, R. Frederick, and V. Jacobson, “RTP: A transport protocol for real-time applications,” Request for Comments 1889, IETF, Audio-Video WG, 1995.Google Scholar
  20. 20.
    A. Vega Garcia, “Mecanismes de controle pour la transmission de l'audio sur l'Internet,” Doctoral Thesis in Computer Science, University of Nice-Sophia Antipolis, Ecole Doctoral SPI, 1996.Google Scholar
  21. 21.
    L. Zhang, “RSVP: A new resource reservation protocol,” in IEEE Network Magazine Vol. 7, pp. 8–18, 1993.Google Scholar

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Marco Roccetti
    • 1
  • Vittorio Ghini
    • 1
  • Giovanni Pau
    • 1
  • Paola Salomoni
    • 1
  • Maria Elena Bonfigli
    • 1
  1. 1.Dipartimento di Scienze dell'InformazioneUniversità di BolognaBolognaItaly

Personalised recommendations