A variable-bit-rate speech coding algorithm based on enhanced mixed excitation linear prediction

A new multi-frame joint quantization algorithm with dynamic weighted inter-frame linear prediction based on mixed excitation linear prediction (MELP) is proposed in this paper. In encoding stage, a super-frame consists of three adjacent single-frames. Fourier magnitudes and aperiodic jitter flag are eliminated. The other parameters are jointly quantized. LSF of the first and third frame are quantized as a 20-dimensional vector. According to the BPVs of super-frame, pitch is quantized with codebooks of dynamic size. In decoding stage, parameters are indexed from corresponding codebook. The LSF of middle frame are predicted from the first and third frame. The weighted factors keep changing in accordance with the BPVs of adjacent five frames. Results show that the reconstruction accuracy of LSF is significantly improved using dynamic weighted inter-frame linear prediction. Meanwhile the coding bit rate is reduced to 0.6 kbps.

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Research on an Embedded Ultra-Low-Bit-Rate Speech Coding Algorithm

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.1951 ◽

2014 ◽

Vol 989-994 ◽

pp. 1951-1954 ◽

Cited By ~ 1

Author(s):

Ye Li ◽

Yan Hong Fan ◽

Fei Yuan ◽

Xiao Mei Xu

Keyword(s):

Speech Coding ◽

Linear Prediction ◽

Transmission Rate ◽

Speech Communication ◽

Bit Rate ◽

Long Distance ◽

Low Bit Rate ◽

Narrow Bandwidth ◽

Mixed Excitation Linear Prediction ◽

Linear Prediction Model

Ultra-low-bit-rate speech coding algorithm was in great demand for many fields such as underwater speech communications. Underwater speech communication for middle-long distance has the characteristics of narrow bandwidth as well as low transmission rate, which makes the underwater speech communication much difficult. Ultra-low-bit-rate speech coding algorithm plays an important role on this occasion. More over, it will be more flexible for the underwater speech communication system if the speech coding algorithm has an embedded structure. The paper introduced the principle of an embedded speech coding algorithm with dual rates at both 300bps and 400bps based on the enhanced mixed excitation linear prediction model. The results show that this embedded ultra-low-bit-rate speech coding algorithm has satisfactory quality under both DRT and MOS test.

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Adaptive variable bit-rate speech coder for wireless applications

10.32920/ryerson.14657373 ◽

2021 ◽

Author(s):

Junhong Chen

Keyword(s):

Wireless Communication ◽

Speech Coding ◽

Speech Quality ◽

Variable Bit Rate ◽

Bit Rate ◽

Wireless Applications ◽

Speech Coder ◽

Joint Channel ◽

Essential Service ◽

Low Rate

In wireless communication, speech is an essential service for which low rate speech coding is a key technique. Reducing the transmission bandwith and achieving higher speech quality are primary concerns in developing new speech coding algorithms. This report develops a joint channel and source controlled adaptive variable bit-rate algorithm to achieve a high speech quality and maintain an efficient spectrum.

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