1、 53556.120122014 . 3 (MPEG4 AUDIO) 53556.12012 27 2002 . 184- , 1.0 2004 . 1 - - - c ( )2 480 3 - 20 2012 . 940- 4 / 14496-3:2009 . -. 3. (/14496-3:2009 Information technology - Coding of audio-visual objects Part 3: Audio) 15 1.02012 ( 8). ( 1 ) , -. () - . , nullnullnullnullnullnullnullnullnullnul
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3、ull , II 53556.120121 12 13 , , 23.1 23.2 .33.3 .43.4 53.5 .53.6 MPEG4 203.7 MPEG4 373.8 50 () .68 () 72 . .91III 53556.120121 53556.12012 . 3 (MPEG4 AUDIO) Digital sound broadcasting.Coding of sound broadcasting signals with redundancy reduction for transfer on digital communication channels. Part
4、III (MPEG-4 audio). General requirements for coding 201309011 ( 64 / ) (Fs) - 16 , 22,05 24 . 7,5 , 10,3 11,25 -, ( 527422007 535372009)., 547112011 -, , - . , ID 547112011 - . , , . , 2766788, 2837689., , -, - Hi-Fi. , ( ), , :CATV ;CDAD ;DAB ;DVD ;ENG ( );HDTV ;IPC (, . .);ISM ( . .).2 : 547112011
5、 . - . MPEG1 III (MPEG1 audio) 547122011 . - . MPEG2, III (MPEG2 audio) 53556.120122 547132011 . . MPEG2, VII. - (MPEG2 AAC) 53556.02009 . . MPEG4, III (MPEG4 audio). 527422007 . . - . 535372009 . ( 20 20000 ) 2766788 -. 2837689 -. - - , 1 , , . (), () . , -, , , .3 , , 3.1 , 53556.02009, , - :3.1.1
6、 : , .3.1.2 AAC: , , lfe - , . program_config_element (). single_channel_element (), channel_pair_element (), coupling_channel_element (), lfe_channel_element () data_stream_element () .3.1.3 : - .3.1.4 : , - .3.1.5 : , ; . .3.1.6 : .3.1.7 : . - .3.1.8 API: .3.1.9 : - .3.1.10 ELD: .3.1.11 EP: .3.1.1
7、2 R: .3.1.13 : LPC. 3.1.14 : - . VQ LSP.3.1.15 LTP: .3.1.16 : single_channel_elements channel_pair_elements . 53556.1201233.1.17 MIDI: .3.1.18 : , , .3.1.19 PS: .3.1.20 TTSI: .3.1.21 VQ: .3.1.22 VXC: . CELP.3.2 3.2.1 , , . . . .+ .- ( ) ( ).+ .- - .* . ./ . , 7/4 -7/4 , -7/4 7/-4 ./ . - , . 3/2 - ,
8、-3/2 .DIV -.| | . | x | = x, x 0;| x | = 0, x = 0;| x | = -x, x 0;Sign (x) = 0, x = 0;Sign (x) = -1, x . = . .= 2:RCU = RCU_ref * #SCE + 0,5 * #LFE + 0,5 * #IndepCouplingCh + 0,4 * #DepCouplingCh + RCU_ref + (RCU_ref - 1) * (2 * #CPE - 1)RCU_ref: RCU, 4#SCE: SCE#CPE: CPE 4 53556.12012143.5.2.3 . - (
9、) 5 LFE (L), (I) (D) , AAC A.L.I.D. 5 AAC AOT 1 2 31 (AAC main) 1.0.0.0 2.0.0.0 5.1.1.12 (AAC LC) 1.0.0.0 2.0.0.0 5.1.0.13 (AAC SSR) 1.0.0.0 2.0.0.0 5.1.0.04 (AAC LTP) 1.0.0.0 2,0.0.0 5.1.0.117 (ER AAC LC) 1.0.0.0 2.0.0.0 5.1.0.019 (ER AAC LTP) 1.0.0.0 2.0.0.0 5.1.0.023 (ER AAC LD) 1.0.0.0 2.0.0.0 5
10、.1.0.0 , , . , - , CELP , AAC, CELP AAC; , , ( ) GA. :1. .2. 20 . :1. 1: :- - - TTSI2. 2: :- .- - TTSI3. 3: :- - TTSI- ; :1. 24 , ( -).2. 24 , ( ).3. 48 , ( ).4. 48 , 5- - -. PCU=16) syncExtensionType; if (syncExtensionType = 0x2b7) 52111bslbfbslbfbslbfbslbfextensionAudioObjectType = GetAudioObjectT
11、ype();if ( extensionAudioObjectType = 5 ) sbrPresentFlag;if (sbrPresentFlag = 1) extensionSamplingFrequencyIndex;if ( extensionSamplingFrequencyIndex = 0xf ) extensionSamplingFrequency;if ( bits_to_decode() = 12 ) 1424uimsbfuimsbfuimsbf 15 53556.1201223 syncExtensionType;if (syncExtesionType = 0x548
12、) psPresentFlag;if ( extensionAudioObjectType = 22 ) sbrPresentFlag;if (sbrPresentFlag = 1) extensionSamplingFrequencyIndex;if ( extensionSamplingFrequencyIndex = 0xf ) extensionSamplingFrequency;extensionChannelConfiguration;11114244bslbfuimsbfuimsbfuimsbfuimsbfuimsbf 16 GetAudioObjectType () GetAudioObjectType()audioObjectType;if (audioObjectType = 31) audioObjectType = 32 + audioObjectTypeExt;return audioObjectType; 56uimsbfu
