amrnb與g.729ab間代數(shù)碼書的轉(zhuǎn)碼技術(shù)研究

1、北京工業(yè)大學(xué)碩士學(xué)位論文AMRNB與G.729AB間代數(shù)碼書的轉(zhuǎn)碼技術(shù)研究姓名：邱建偉申請學(xué)位級別：碩士專業(yè)：電路與系統(tǒng)指導(dǎo)教師：鮑長春20090401ABSTRACTABSTRACTResearchonparametertranscodingalgorithmsbetweenAMRNBandG729abhasbeenafocusedtopicinspeechcodingfieldrecentlyTranscodingtechnique

2、sofeodebookalerelatedwithspeechqualityandcomputationalcomplexityIntermofit，sometranscodingtechniquesofalgebraiccodebookbetweenAMRNBandG729ABareproposedinthisthesisFirstlythecodebookstructures，searchingalgorithms，bitsallo

3、cation，encodingmethodsinbothofthecodecsarecomparedandanalyzedindetailAccordingtodifferenttranscodingrates，varioustranscodingtechniquesbasedonparameterdomain，excitationdomainorspeechdomainareadoptedtosatisfyboththerequire

4、mentofimprovingspeechqualityandreducingcomputationalcomplexitySecondlyafteranalyzingthedistributionofcodebookpulseofAMRNBat122kb／sandG729abaswellasobservingthematchingrateofcodebooksbetweenvoiceframesandunvoiceframes，ran

5、domnumbermappingandpermutation&combinationmappingcodebookparametertranscodingalgorithmsarepresentedinthisthesisItisshownbyexperimentresultsthatbothalgorithmsareabletoreducetranscodingcomputationalcomplexityby98％，withacce

6、ptablespeechquanlityThirdlythealgebraiccodebooktranscodingbasedonpulsepositionreconstructionisproposedinthisthesisthroughtheresearchondepthfirsttreealgorithmsofcodebookItisshownbyresultsthat，comparingwiththemethodinwhich

7、thesearchrangeisnotshorten，theproposedalgorithmcanreducethecodebooksearchcomputationalcomplexityby30％orabove，aswellasguaranteethetranscodedspeechqualityFinally，byusingtheprobabilitystatisticsmethodsandtakingadvantageofth

8、eeffectivenessofdescriptionofstochasticprocessesofHMM，acodebookparametertranscodingalgorithmbasedonHMMisproposedandrealizedinthisthesisComparingwiththetraditionalspeechdomaincodebooktranscoding，thisalgorithmcanreducecomp