MP-CELP speech coding based on multipulse vector quantization and fast search

American Journal of Applied Sciences

2012

Problem statement:In modern speech communication at low bit rate, speech coding deteriorates the characteristics of the coded speech significantly. Considering the dialects in Thai, the coding quality of four main dialects spoken by Thai people residing in four core region including central, north, northeast and south regions has not been studied. Approach: This study presents a comparative study of the coding quality of four main Thai dialects by using different low-bit-rate speech coders including the Conjugate Structure Algebraic Code Excited Linear Predictive (CS-ACELP) coder and the Multi-Pulse based Code Excited Linear Predictive (MP-CELP) coder. The objective and subjective tests have been conducted to evaluate the coding quality of four main dialects. Results: From the experimental results, both tests show that the coding quality of North dialect is highest, meanwhile the coding quality of Northeast dialect is lowest. Moreover, the coding quality of male speech is mostly higher than that of female speech. Conclusion: From the study, it can be obviously seen that the coding quality of all Thai dialects are different.

“…3 (Taumi et al, 1996;Ozawa et al, 1997). The input speech of 10 ms frame is processed through Linear Prediction (LP) and pitch analysis.…”

Section: Mp-celp Codermentioning

confidence: 99%

Speech Compression of Thai Dialects with Low-Bit-Rate Speech Coders

American Journal of Applied Sciences

2012

“…3 (Ozawa et al, 1996). The input speech of a 10-mslength frame is processed through Linear Prediction (LP) and pitch analysis.…”

Section: Mp-celp Core Codermentioning

confidence: 99%

“…A few years later, MP-CELP speech coder has been developed to be a scalable coder. With the flexible functionality, this coder employs the multipulse excitation which the number of pulses in fixedentry codebook is selective for bitrate scalability and multiple bitrate functionality according to the MPEG-4 CELP speech coder requirements (Ozawa et al, 1996;Chomphan, 2010b) In the MP-CELP speech coder, amplitudes or signs for generating the multi-pulse excitation are vector quantized simultaneously. Moreover, to improve speech quality for background noise conditions, the adaptive pulse location restriction method are applied .…”

Section: Introductionmentioning

confidence: 99%

Speech Compression for Noise-Corrupted Thai Expressive Speech

Journal of Computer Science

2011

Problem statement: In speech communication, speech coding aims at preserving the speech quality with lower coding bitrate. When considering the communication environment, various types of noises deteriorates the speech quality. The expressive speech with different speaking styles may cause different speech quality with the same coding method. Approach: This research proposed a study of speech compression for noise-corrupted Thai expressive speech by using two coding methods of CS-ACELP and MP-CELP. The speech material included a hundredmale speech utterances and a hundred female speech utterances. Four speaking styles included enjoyable, sad, angry and reading styles. Five sentences of Thai speech were chosen. Three types of noises were included (train, car and air conditioner). Five levels of each type of noise were varied from 0-20 dB. The subjective test of mean opinion score was exploited in the evaluation process. Results: The experimental results showed that CS-ACELP gave the better speech quality than that of MP-CELP at all three bitrates of 6000, 8600-12600 bps. When considering the levels of noise, the 20-dB noise gave the best speech quality, while 0-dB noise gave the worst speech quality. When considering the speech gender, female speech gave the better results than that of male speech. When considering the types of noise, the airconditioner noise gave the best speech quality, while the train noise gave the worst speech quality. Conclusion: From the study, it can be seen that coding methods, types of noise, levels of noise, speech gender influence on the coding speech quality.

“…2 (Taumi et al, 1996;Ozawa et al, 1996). The input speech of 10 ms frame is processed through Linear Prediction (LP) and pitch analysis.…”

Section: Mp-celp Core Codermentioning

confidence: 99%

“…This study proposes a bitrate scalable tonal language speech coder based on a multi-pulse based code excited linear predictive coding (Taumi et al, 1996;Ozawa et al, 1996;Sen et al, 2005;Ghrare et al, 2009). The proposed coder provides the bitrate scalabilities which is effective in multimedia communications.…”

Section: Introductionmentioning

confidence: 99%

High Pitch Delay Resolution Technique for Tonal Language Speech Coding Based on Multi-Pulse Based Code Excited Linear Prediction Algorithm

Journal of Computer Science

2011

Problem statement:In spontaneous speech communication, speech coding is an important process that should be taken into account, since the quality of coded speech depends on the efficiency of the speech coding algorithm. As for tonal language which tone plays important role not only on the naturalness and also the intelligibility of the speech, tone must be treated appropriately. Approach: This study proposes a modification of flexible Multi-Pulse based Code Excited Linear Predictive (MP-CELP) coder with multiple bitrates and bitrate scalabilities for tonal language speech in the multimedia applications. The coder consists of a core coder and bitrate scalable tools. The High Pitch Delay Resolutions (HPDR) are applied to the adaptive codebook of core coder for tonal language speech quality improvement. The bitrate scalable tool employs multi-stage excitation coding based on an embedded-coding approach. The multi-pulse excitation codebook at each stage is adaptively produced depending on the selected excitation signal at the previous stage. Results: The experimental results show that the speech quality of the proposed coder is improved above the speech quality of the conventional coder without pitch-resolution adaptation. Conclusion: From the study, it is a strong evidence to further apply the proposed technique in the speech coding systems or other speech processing technologies.