2 Routines for handling .mp3 files
4 Part of the swftools package.
6 Copyright (c) 2005 Joel Yliluoma <bisqwit@iki.fi>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
35 struct MP3Frame* next;
39 static const unsigned BR_mpeg1[16] = {0,32,40,48,56,64,80,96,112,128,160,192,224,256,320,0};
40 static const unsigned BR_mpeg2[16] = {0,8, 16,24,32,40,48,56, 64, 80, 96,112,128,144,160,0};
41 static const unsigned BR_reserved[16] = {0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0};
42 static const unsigned*const BR[4] = {BR_mpeg2, BR_reserved, BR_mpeg2, BR_mpeg1};
44 static const unsigned SR_mpeg1[4] = {44100,48000,32000,0};
45 static const unsigned SR_mpeg2[4] = {22050,24000,16000,0};
46 static const unsigned SR_mpeg25[4] = {11025,12000,8000,0};
47 static const unsigned SR_reserved[4] = {0,0,0,0};
48 static const unsigned*const SR[4] = {SR_mpeg25, SR_reserved, SR_mpeg2, SR_mpeg1};
50 int mp3_read(struct MP3*mp3, const char* filename)
52 struct MP3Frame* root = 0;
53 struct MP3Frame** cur = &root;
55 unsigned totalsize = 0;
56 unsigned first_samprate = 0;
58 int first_chanmode = -1;
60 FILE*fi = fopen(filename, "rb");
65 unsigned char FrameBuf[2048];
66 unsigned char* hdr = FrameBuf;
67 unsigned char* data = FrameBuf+4;
68 unsigned char* frdata;
70 unsigned char mpegver;
77 if(fread(hdr,1,4,fi) < 4) break;
79 if(hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3')
82 unsigned id3_size = 0;
83 if(fread(FrameBuf, 1, 6, fi) < 6) break;
85 id3_size = (FrameBuf[5])
88 + (FrameBuf[2] << 21);
89 fprintf(stderr, "readMP3: skipping ID3 tag (10+%u bytes)\n", id3_size);
90 if(fseek(fi, id3_size, SEEK_CUR) < 0)
92 /* Cannot seek? Try reading. */
93 char* tmpbuf = (char*)malloc(id3_size);
97 fprintf(stderr, "readMP3: fseek and malloc both failed?\n");
100 nread = fread(tmpbuf, 1, id3_size, fi);
102 if(nread < id3_size) break;
109 || (hdr[1] & 0xE0) != 0xE0)
111 fprintf(stderr, "readMP3: invalid header %02X %02X %02X %02X\n",
112 hdr[0],hdr[1],hdr[2],hdr[3]);
116 mpegver = (hdr[1] >> 3) & 0x03;
118 bitrate = BR[mpegver][ (hdr[2] >> 4) & 0x0F ] * 1000;
119 samprate = SR[mpegver][ (hdr[2] >> 2) & 0x03 ];
120 chanmode = (hdr[3] >> 6) & 0x03;
122 padding = (hdr[2] & 2) ? 1 : 0;
124 if(!bitrate || !samprate)
129 if(!first_samprate) first_samprate = samprate;
130 else if(first_samprate != samprate)
132 /* Sampling rate changed?!? */
133 fprintf(stderr, "readMP3: sampling rate changed?\n");
136 if(first_chanmode<0) first_chanmode = chanmode;
137 else if(first_chanmode != chanmode)
139 /* Channel mode changed?!? */
140 fprintf(stderr, "readMP3: chanmode changed?\n");
144 framesize = ((mpegver == 3 ? 144 : 72) * bitrate) / samprate + padding;
147 fprintf(stderr, "%02X %02X %02X %02X - bitrate=%u,samprate=%u,chanmode=%u,padding=%u,framesize=%u\n",
148 hdr[0],hdr[1],hdr[2],hdr[3],bitrate,samprate,chanmode,padding,framesize);
150 if(framesize > sizeof(FrameBuf)) break;
151 if(fread(data, 1, framesize - 4, fi) < framesize-4)
153 fprintf(stderr, "readMP3: short read at frame %u\n", nframes);
157 if(!bitrate || !samprate) continue;
159 frdata = (unsigned char*)malloc(framesize);
162 fprintf(stderr, "readMP3: malloc failed\n");
166 *cur = (struct MP3Frame*)malloc(sizeof(*root));
169 fprintf(stderr, "readMP3: malloc failed\n");
175 (*cur)->bitrate = bitrate;
176 (*cur)->samprate = samprate;
177 (*cur)->chanmode = chanmode;
178 (*cur)->framesize = framesize;
179 (*cur)->data = frdata;
181 memcpy(frdata, FrameBuf, framesize);
184 totalsize += framesize;
189 fprintf(stderr, "readMP3: not a MP3 file\n");
195 fprintf(stderr, "readMP3: read %u frames (%u bytes)\n", nframes, totalsize);
198 mp3->SampRate = first_samprate;
199 mp3->Channels = first_chanmode == 3 ? 1 : 2;
200 mp3->NumFrames = nframes;
201 mp3->size = totalsize;
202 mp3->data = (unsigned char*)malloc(mp3->size);
207 for(it=root; it; it=it->next)
209 memcpy(mp3->data + pos, it->data, it->framesize);
210 pos += it->framesize;
215 fprintf(stderr, "readMP3: malloc failed\n");
220 struct MP3Frame* next = root->next;
227 return mp3->data != NULL;
230 void mp3_clear(struct MP3*mp3)