1、 53556.10 2014 III (MPEG4 AUDIO) ISO/IEC 14496-3:2009 (NEQ) 53556.102014 II 1 480 2 480 3 18 2014 . 386- 4 / 144963:2009 . . 3. (ISO/IEC 144963:2009 Information technology - Coding of audio-visual objects - Part 3: Audio, NEQ) 1 5 1.02012 ( 8). ( 1 ) , . () . , (gost.ru) , 2014 , 53556.102014 1 III
2、(MPEG4 AUDIO) Sound broadcasting digital. Coding of signals of sound broadcasting with reduction of redundancy for transfer on digital communication channels. Part III (MPEG4 audio). Oversampled audio 2015 01 01 1 MPEG4 . 2 : Audio Channel DSD, . Audio Frame (), . Audio Channel Number , . , . Frame
3、, . 1/75 . Reserved , Reserved (), . Reserved . Silence Pattern DSD : ; 4 4 . Direct Stream Digital . Direct Stream Transfer , DSD - . Half Probability , DSD , Ptable, 1/2. Mapping . 53556.102014 2 Prediction Filter , , DSD. . Probability Table , DSD . Sampling Frequency DSD 64 * 44,1 , 128 * 44,1 2
4、56 * 44,1 . Segmentation . 3 3.1 a b a b . msb 0. a =0) CoefFilter_NrCoef_Nr -= trunc(Delta8+4)/8) else CoefFilter_NrCoef_Nr += trunc(-Delta8+3)/8) 1 BsMsbf 53556.102014 9 14 Probability_Tables Probability_Tables() for (Ptable Nr=0; Ptable Nr 0 , Element, n : 2n-1 Nr_ Of_ Elements 8)|(A7) Ptable_Nr3
5、, Ptable_LenPtable_Nr-1); CAPtable_NrEntry_Nr+; CWPtable_NrEntry_Nr += EChannel_NrBit_Nr; Start = Stop; Ptable : for (Ptable_Nr=0; Ptable_NrNr_Of_Ptables; Ptable_Nr+) for (Entry_Nr=0; Entry_NrPtable_LenPtable_Nr; Entry_Nr+) if (CAPtable_NrEntry_Nr = 0) P_minPtable_NrEntry_Nr = 1; else P_minPtable_Nr
6、Entry_Nr = min(max(p, 1), 128); P_min Ptables. Ptable , (P_one ), : P_min Ptable_Nr Entry_Nr P_one Ptable_Nr Entry_Nr 1 . 53556.102014 26 A () A.1 : (), . , . , , . , , () . . . A.1.1 ( ) . -, , , “ . , . -, ( , ). - . , b 0, 1 M=37,632 , 1/75 , 2,8224 MS/. A.1.2 () . b, e, . h e , b. z-1H(z), , , ,
7、 , . FIR , (MMSE). MMSE , : , M M Ln = n = i = n = h i b n - i - b n 221 1 1 L , Coded_Pred_Order+1. h. FIR, , . , , 9- 256. CoefFilter_Nr Coef_Nr, Filter_Nr , Coef_Nr - , . z . q z , , Q (z). b z , b q, z. . e (XOR) b q. , e, , . A.1.3 , e , , . , 1 e p, 0 (1-p). Nbits, e, : N b it s = - p p + - p
8、- p .22lo g 1 lo g 1 53556.102014 27 , 90 % , p = 0,1 Nbits = 0,47. , 2. , , , , , . , “0“ “1“. , , , ( ). , P(e=0), , , P (e=0) = 1 - P (e=1), : t P (e=1), . A.1.4 “ “, , . , . / . , , , , . , ( ), , . e p, . 53556.102014 28 1 / 144963:2009 . . 3. (/144963:2009 Information technology - Coding of audio-visual objects - Part 3: Audio)
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