scholarly journals Bit rate reduction of mixed excitation linear prediction coder by Lempel-Ziv segment quantization

2009 ◽  
Vol 30 (2) ◽  
pp. 136-138
Author(s):  
Minoru Kohata ◽  
Motoyuki Suzuki ◽  
Akinori Ito ◽  
Shozo Makino
Keyword(s):  
Linear Prediction ◽  
Bit Rate ◽  
Rate Reduction ◽  
Mixed Excitation Linear Prediction

Speech Coding Algorithm with Dynamic Weighted Inter-Frame Linear Prediction

2013 ◽  
Vol 798-799 ◽  
pp. 769-772
Author(s):  
Zhao An Su ◽  
Chun Di Xiu
Keyword(s):  
Speech Coding ◽  
Linear Prediction ◽  
The Other ◽  
Dimensional Vector ◽  
Bit Rate ◽  
Reconstruction Accuracy ◽  
Mixed Excitation Linear Prediction ◽  
Super Frame ◽  
Inter Frame

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.

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

2014 ◽  
Vol 989-994 ◽  
pp. 1951-1954 ◽  
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.

A Research of Intra Prediction Coding with Variance of Prediction Mode Number

2015 ◽  
Vol 719-720 ◽  
pp. 1177-1183
Author(s):  
Wei Zheng ◽  
Long Ye ◽  
Jing Ling Wang ◽  
Qin Zhang
Keyword(s):  
State Of The Art ◽  
Intra Prediction ◽  
Mode Number ◽  
Bit Rate ◽  
Rate Reduction ◽  
Directional Information ◽  
Mode Index ◽  
Residual Image ◽  
Prediction Mode ◽  
Direction Information

Intra prediction is a key step in H.264/AVC to improve the coding performance with the idea that removing the directional redundancy among neighboring blocks. In order to cover more directional information existed in the image frames, there are usually many prediction modes can be selected in the state-of-the-art coding frameworks, but more bits are also needed to encode the prediction mode index information, then how to achieve the maximum overall bit-rate reduction became a problem. In this paper, 16 kinds of prediction modes are adopted by considering the direction information for 8x8 image blocks. Through calculating the bit-rate both for the mode index and residual image under different number of prediction modes, we obtain the most suitable prediction mode number relatively from the graphs. Experimental results show that, with the increase of prediction mode number, the residual information decreases obviously, and the sum of residual information and prediction mode index information also decreases but levels off after reaching a certain mode number, even has an obviously rising trend.

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