1、 53556.9 2013 III (MPEG4 audio) MPEG1/2 Audio MPEG4 ISO/IEC 14496-3:2009 (NEQ) 53556.92013 II 1 - - c ( ) 2 480 3 22 2013 . 1721- 4 / 14496-3:2009 . . 3. (ISO/IEC14496-3:2009 Information technology - Coding of audio-visual objects - Part 3: Audio (NEQ) 5 1.02012 ( 8). ( 1 ) , . () . , (gost.ru) , 20
2、14 , 53556.92013 1 . III (MPEG4 AUDIO) MPEG1/2 Audio MPEG4 Sound broadcasting digital. Coding of signals of sound broadcasting with reduction of redundancy for transfer on digital communication channels. A part III (MPEG4 audio). Main positions MPEG1/2 Audio in MPEG4 20140901 1 MPEG1/2 MPEG4 MPEG4 M
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4、on . 3 : single_channel_element () s lfe_element () s ; channel_pair_element () s ; 1 2 , single_channel_element (), , channel_pair_element (). 53556.92013 2 4 4.1 1 2 . 4.2 3 mp3_channel_elements. mp3_channel_element 3 54711 54712: syncword (12 ) mp3_channel_element ( , error_check, ) . main_data_b
5、egin (9/8 ) , MPEG1/2 3, . main_data () 54711 54712. AudioSpecificConfig (). mp3_channel_elements, , 5 3 , 3 , 54711 54712. , 54711-2012, 54712-2012 ( 576 ). 5.1 1 bitrate_index . 1 bitrate_index , / bitrate_index 8, 11,025, 12 16, 22,05, 24 (. 54712) 32, 44,1, 48 (. 54711), 0000 0001 8 8 32 0010 16
6、 16 40 0011 24 24 48 0100 32 32 56 0101 40 40 64 0110 48 48 80 0111 56 56 96 1000 64 64 112 1001 80 128 1010 96 160 1011 112 192 1100 128 224 1101 144 256 1110 160 320 1111 5.2 , AudioSpecificConfig, sampling_frequency , 2. 53556.92013 3 2 sampling_frequency , AudioSpecificconfig () sampling_frequen
7、cy 00 11,025 01 12 10 8 11 5.3 11,025 . 5.4 scalefactor . , 54711 54712, A. 54711 54712 , , 1,0. 53556.92013 4 () .1 8 , , 576 index_of_start index_of_end 0 12 0 11 1 12 12 23 2 12 24 35 3 12 36 47 4 12 48 59 5 12 60 71 6 16 72 87 7 20 88 107 8 24 108 131 9 28 132 159 10 32 160 191 11 40 192 231 12
8、48 232 279 13 56 280 335 14 64 336 399 15 76 400 475 16 90 476 565 17 2 566 567 18 2 568 569 19 2 570 571 20 2 572 573 .2 8 , , 192 index_of_start index_of_end 0 8 0 7 1 8 8 15 2 8 16 23 3 12 24 35 4 16 36 51 5 20 52 71 6 24 72 95 7 28 96 123 8 36 124 159 9 2 160 161 10 2 162 163 11 2 164 165 53556.
9、92013 5 .3 11,025 , , 576 index_of_start index_of_end 0 6 0 5 1 6 6 11 2 6 12 17 3 6 18 23 4 6 24 29 5 6 30 35 6 8 36 43 7 10 44 53 8 12 54 65 9 14 66 79 10 16 80 95 11 20 96 115 12 24 116 139 13 28 140 167 14 32 168 199 15 38 200 237 16 46 238 283 17 52 284 335 18 60 336 395 19 68 396 463 20 58 464
10、 521 .4 11,025 , , 192 scalefactor index_of_start index_of_end 0 4 0 3 1 4 4 7 2 4 8 11 3 6 12 17 4 8 18 25 5 10 26 35 6 12 36 47 7 14 48 61 8 18 62 79 9 24 80 103 10 30 104 133 11 40 134 173 53556.92013 6 .5 12 , , 576 index_of_start index_of_end 0 6 0 5 1 6 6 11 2 6 12 17 3 6 18 23 4 6 24 29 5 6 3
11、0 35 6 8 36 43 7 10 44 53 8 12 54 65 9 14 66 79 10 16 80 95 11 20 96 115 12 24 116 139 13 28 140 167 14 32 168 199 15 38 200 237 16 46 238 283 17 52 284 335 18 60 336 395 19 68 396 463 20 58 464 521 .6 12 , , 192 index_of_start index_of_end 0 4 0 3 1 4 4 7 2 4 8 11 3 6 12 17 4 8 18 25 5 10 26 35 6 1
12、2 36 47 7 14 48 61 8 18 62 79 9 24 80 103 10 30 104 133 11 40 134 173 53556.92013 7 () MPEG1/2 3 mp3_channel_elements main_data () . , main_data () . mp3_channel_element . H SI . header () . main_data_begin . CRC . 53556.92013 8 () mp3_channel_elements MPEG1/2 3 .1 mp3_channel_elements, , , MPEG1/2
13、3, 54711 54712: mp3_channel_element ; mp3_channel_element : syncword IDex; bitrate_index; main_data_begin; crc_word ; . .2. , 54711 54712, syncword. : header () syncword; 11 bslbf Idex; 1 bslbf syncword 1111 1111 111. IDex , ID . 0 , 54711 54712. IDex ID: IDex ID 0 0 8, 11,025, 12 1 0 16, 22,05, 24
14、(. 54712), 1 1 32, 44,1, 48 (. 54711), .3. : bitrate_index ( bitrate_index, padding_bit, (), 1) ( ). 2) , mp3_channel_element. 3) , mp3_channel_element main_data_begin . 4) main_data_begin . 5) main_data_begin , main_data . 6) main_data_begin MPEG1/2 3. 7) ( ) main_data: 53556.92013 9, , . 8) ( ) ( , part_2_3_length): , , main_data . 9) : . , . . , MPEG1/2 3. main_data_begin . . , bitrate_index , mp3_channel_element. . 24 ( , ), . (main_data_begin=0). , 960 (7680 ), , , 576 ( 8 ), 417 ( 11,025 ), 384 ( 12 ), 720 ( 16 ), 522 ( 22,05 ), 480 ( 24 ). main_data_begin