0 "none" 1 "50/15 microsecs" 2 "reserved" must not be used ! 3 "CCITT J 17"
* TRAILER
at end of file - 128 bytes
offset type len name -------------------------------------------- 0 char 3 "TAG" 3 char 30 title 33 char 30 artist 63 char 30 album 93 char 4 year 97 char 30 comments 127 byte 1 genre --------------------------------------------
加个头导出即可。
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{
unsigned short sync:11;
unsigned short version:2;
unsigned short lay:2;
unsigned short error_protection:1;
unsigned short bitrate_index:4;
unsigned short sampling_freq:2;
unsigned short padding:1;
unsigned short extension:1;
unsigned short mode:2;
unsigned short mode_ext:2;
unsigned short copyright:1;
unsigned short orginal:1;
unsigned short emphasis:2;
}Header; struct Tail
{
char tag[3];
char title[30];
char artist[30];
char album[30];
char year[4];
char comments[30];
byte genre;
}Tail;
memset(&Header,0,sizeof(Header));
memset(&Tail,0,sizeof(Tail)); CFile fp;
fp.Open("c:\\a.mp3",CFile::modeRead);
fp.Read(&Header,sizeof(Header));
fp.SeekToBegin();
fp.Seek(fp.GetLength()-sizeof(Tail),0);
fp.Read(&Tail,sizeof(Tail));
fp.Close();
如上
---------------------------------------------------------------
Mpeg 1.0/2.0 LayersI, II and III header and trailer formats
-----------------------------------------------------------
[email protected]
With corrections by Fausto Richetti Blanco
* HEADER
bits name comments
--------------------------------------------------
11 sync 0xFFF
2 version 1=mpeg1.0, 0=mpeg2.0
2 lay 4-lay = layerI, II or III
1 error protection 0=yes, 1=no
4 bitrate_index see table below
2 sampling_freq see table below
1 padding
1 extension see table below
2 mode see table below
2 mode_ext used with "joint stereo" mode
1 copyright 0=no 1=yes
1 original 0=no 1=yes
2 emphasis see table below
--------------------------------------------------
- bitrate_index
. mpeg1.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14
layer1 32 64 96 128 160 192 224 256 288 320 352 384 416 448
layer2 32 48 56 64 80 96 112 128 160 192 224 256 320 384
layer3 32 40 48 56 64 80 96 112 128 160 192 224 256 320
. mpeg2.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14
layer1 32 48 56 64 80 96 112 128 144 160 176 192 224 256
layer2 8 16 24 32 40 48 56 64 80 96 112 128 144 160
layer3 8 16 24 32 40 48 56 64 80 96 112 128 144 160
- sampling_freq
. mpeg1.0
0 1 2
44100 48000 32000
. mpeg2.0
0 1 2
22050 24000 16000
- mode:
0 "stereo"
1 "joint stereo"
2 "dual channel"
3 "single channel"
- mode extension:
0 MPG_MD_LR_LR
1 MPG_MD_LR_I
2 MPG_MD_MS_LR
3 MPG_MD_MS_I
jsbound :
mode_ext 0 1 2 3
layer
1 4 8 12 16
2 4 8 12 16
3 0 4 8 16
- emphasis:
0 "none"
1 "50/15 microsecs"
2 "reserved" must not be used !
3 "CCITT J 17"
* TRAILER
at end of file - 128 bytes
offset type len name
--------------------------------------------
0 char 3 "TAG"
3 char 30 title
33 char 30 artist
63 char 30 album
93 char 4 year
97 char 30 comments
127 byte 1 genre
--------------------------------------------
- genre :
0 "Blues"
1 "Classic Rock"
2 "Country"
3 "Dance"
4 "Disco"
5 "Funk"
6 "Grunge"
7 "Hip-Hop"
8 "Jazz"
9 "Metal"
10 "New Age"
11 "Oldies"
12 "Other"
13 "Pop"
14 "R&B"
15 "Rap"
16 "Reggae"
17 "Rock"
18 "Techno"
19 "Industrial"
20 "Alternative"
21 "Ska"
22 "Death Metal"
23 "Pranks"
24 "Soundtrack"
25 "Euro-Techno"
26 "Ambient"
27 "Trip-Hop"
28 "Vocal"
29 "Jazz+Funk"
30 "Fusion"
31 "Trance"
32 "Classical"
33 "Instrumental"
34 "Acid"
35 "House"
36 "Game"
37 "Sound Clip"
38 "Gospel"
39 "Noise"
40 "AlternRock"
41 "Bass"
42 "Soul"
43 "Punk"
44 "Space"
45 "Meditative"
46 "Instrumental Pop"
47 "Instrumental Rock"
48 "Ethnic"
49 "Gothic"
50 "Darkwave"
51 "Techno-Industrial"
52 "Electronic"
53 "Pop-Folk"
54 "Eurodance"
55 "Dream"
56 "Southern Rock"
57 "Comedy"
58 "Cult"
59 "Gangsta"
60 "Top 40"
61 "Christian Rap"
62 "Pop/Funk"
63 "Jungle"
64 "Native American"
65 "Cabaret"
66 "New Wave"
67 "Psychadelic"
68 "Rave"
69 "Showtunes"
70 "Trailer"
71 "Lo-Fi"
72 "Tribal"
73 "Acid Punk"
74 "Acid Jazz"
75 "Polka"
76 "Retro"
77 "Musical"
78 "Rock & Roll"
79 "Hard Rock"
80 "Unknown"
- frame length :
. mpeg1.0
layer1 :
(48000*bitrate)/sampling_freq + padding
layer2&3:
(144000*bitrate)/sampling_freq + padding
. mpeg2.0
layer1 :
(24000*bitrate)/sampling_freq + padding
layer2&3 :
(72000*bitrate)/sampling_freq + padding
{
const unsigned char *const p = headerptr;
static const char abl2[16] =
{ 0, 7, 7, 7, 0, 7, 0, 0, 0, 0, 0, 8, 8, 8, 8, 8 };
if ((p[0] & 0xFF) != 0xFF)
return FALSE; /* first 8 bits must be '1' */
if ((p[1] & 0xE0) != 0xE0)
return FALSE; /* next 3 bits are also */
if ((p[1] & 0x18) == 0x08)
return FALSE; /* no MPEG-1, -2 or -2.5 */
if ((p[1] & 0x06) == 0x00)
return FALSE; /* no Layer I, II and III */
if ((p[2] & 0xF0) == 0xF0)
return FALSE; /* bad bitrate */
if ((p[2] & 0x0C) == 0x0C)
return FALSE; /* no sample frequency with (32,44.1,48)/(1,2,4) */
if ((p[1] & 0x18) == 0x18 && (p[1] & 0x06) == 0x04
&& abl2[p[2] >> 4] & (1 << (p[3] >> 6)))
return FALSE;
if ((p[3] & 3) == 2)
return FALSE; /* reserved enphasis mode */
return TRUE;
}
ID3v1佔用文件末尾128字節，ID3v2載文件首部，長度不定
其他的测试中。
http://www.24bc.com/NewPoint.htm