Towards iLBC speech coding at lower rates through a new formulation of the start state search

Christopher M. Garrido, Manohar Murthi, Søren Vang Andersen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Citations (Scopus)

Abstract

The Internet Low Bit-rate Coder (iLBC) has emerged as a candidate for Voice over Internet Protocol (VoIP) applications. By avoiding the inter-frame coding dependencies endemic to many speech coders such as those based on Code Excited Linear Prediction, iLBC is able to achieve superior robustness to packet loss. In addition to robustness to packet loss, a VoIP codec should possess the agility to adjust its source coding rate in order to react to network congestion and to be amenable to joint source channel coding for wireless channels. Towards this end, we develop a new formulation of the iLBC encoding process that allows for a variable rate iLBC. In particular, we demonstrate how the LP excitation signal is constructed from a much shorter vector of 'start state' samples through a non-square synthesis matrix that captures the effects of the Adaptive Codebook operations. With this new framework, the search and quantization of the start state is re-formulated as an Analysis by Synthesis matching problem. We demonstrate how a Multi-Pulse (MP) approach can be utilized to effect a variable rate coding solution for this new framework. A variable rate coder with the MP start state achieves better performance than the Adaptive Multi-Rate (AMR) coder at 12.2 and 10.2 kbps for packet loss rates greater than 4 %.

Original languageEnglish
Title of host publicationICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
VolumeI
ISBN (Print)0780388747, 9780780388741
DOIs
StatePublished - Jan 1 2005
Event2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05 - Philadelphia, PA, United States
Duration: Mar 18 2005Mar 23 2005

Other

Other2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05
CountryUnited States
CityPhiladelphia, PA
Period3/18/053/23/05

Fingerprint

Speech coding
coders
coding
Packet loss
Internet
formulations
Internet protocols
Channel coding
linear prediction
congestion
synthesis
pulses

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Signal Processing
  • Acoustics and Ultrasonics

Cite this

Garrido, C. M., Murthi, M., & Andersen, S. V. (2005). Towards iLBC speech coding at lower rates through a new formulation of the start state search. In ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings (Vol. I). [1415227] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ICASSP.2005.1415227

Towards iLBC speech coding at lower rates through a new formulation of the start state search. / Garrido, Christopher M.; Murthi, Manohar; Andersen, Søren Vang.

ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. Vol. I Institute of Electrical and Electronics Engineers Inc., 2005. 1415227.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Garrido, CM, Murthi, M & Andersen, SV 2005, Towards iLBC speech coding at lower rates through a new formulation of the start state search. in ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. vol. I, 1415227, Institute of Electrical and Electronics Engineers Inc., 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05, Philadelphia, PA, United States, 3/18/05. https://doi.org/10.1109/ICASSP.2005.1415227
Garrido CM, Murthi M, Andersen SV. Towards iLBC speech coding at lower rates through a new formulation of the start state search. In ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. Vol. I. Institute of Electrical and Electronics Engineers Inc. 2005. 1415227 https://doi.org/10.1109/ICASSP.2005.1415227
Garrido, Christopher M. ; Murthi, Manohar ; Andersen, Søren Vang. / Towards iLBC speech coding at lower rates through a new formulation of the start state search. ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. Vol. I Institute of Electrical and Electronics Engineers Inc., 2005.
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