NDLI: Design of a variable half rate speech codec

Content Provider	IEEE Xplore Digital Library
Author	Hosang Sung Sangwon Kang Dongwon Lee
Copyright Year	1999
Description	Author affiliation: Dept. of Control & Instrum. Eng., Hanyang Univ., Ansan, South Korea (Hosang Sung)
Abstract	In this paper, we combined generalized analysis-by-synthesis (AbS) structure and an algebraic excitation scheme to propose a variable half rate speech codec. The proposed codec operates on the speech frame of 20 ms at a sampling rate of 8 kHz. Also we introduce an efficient voicing detection algorithm using both frame energy and acoustic parameters to detect the voiced, unvoiced and silence region. 4 kb/s speech codec for the voiced region uses the generalized AbS structure which is efficient for the low bit rate speech codec. The generalized AbS structure is used for the relaxed CELP (RCELP) and it can reduce the bitrate for the pitch information by linear interpolation of the pitch delay. LP coefficients are converted to line spectrum pairs (LSP) and quantized using a predictive 2-stage VQ. A low complexity algebraic codebook which uses a shifting method is used for the fixed codebook excitation. 4 kb/s speech codec for the unvoiced region is same as that for the voiced region, except that the latter uses an open loop pitch lag in the whole frame. Also 1 kb/s codec is designed for the silence and background noise region. Experiments show that the variable half rate codec provides the average bit rate of about 2.63 kb/s for the test sentences whose voice activity factor (VAF) is 0.47. The mean opinion score (MOS) of the proposed variable half rate codec is 3.69.
Starting Page	1525
Ending Page	1529
File Size	468243
Page Count	5
File Format	PDF
ISBN	0780354354
ISSN	10903038
DOI	10.1109/VETECF.1999.801549
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	1999-09-19
Publisher Place	The Netherlands
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Speech codecs Bit rate Speech analysis Sampling methods Detection algorithms Acoustic signal detection Interpolation Delay Background noise Testing
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in