42dd7539f647b1e1051870f673fc2f300cfa4a4d
[paraslash.git] / mp3_afh.c
1 /* Copyright (C) 2003 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file mp3_afh.c para_server's mp3 audio format handler */
4
5 /*
6 * This file is based in part on mp3tech.c and mp3tech.h, Copyright (C)
7 * 2000-2001 Cedric Tefft <cedric@earthling.net>, which in turn is based
8 * in part on
9 *
10 * * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
11 * * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and
12 * Johannes Overmann <overmann@iname.com>
13 */
14
15 #include <regex.h>
16
17 #include "para.h"
18 #include "error.h"
19 #include "afh.h"
20 #include "string.h"
21 #include "fd.h"
22
23 /*
24 * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
25 * to see before we decide we are looking at a real MP3 file
26 */
27 #define MIN_CONSEC_GOOD_FRAMES 4
28 #define FRAME_HEADER_SIZE 4
29 #define MIN_FRAME_SIZE 21
30
31 struct mp3header {
32 unsigned long sync;
33 unsigned int version;
34 unsigned int layer;
35 unsigned int crc;
36 unsigned int bitrate;
37 unsigned int freq;
38 unsigned int padding;
39 unsigned int mode;
40 unsigned int copyright;
41 unsigned int original;
42 unsigned int emphasis;
43 };
44
45 static const int frequencies[3][4] = {
46 {22050,24000,16000,50000}, /* MPEG 2.0 */
47 {44100,48000,32000,50000}, /* MPEG 1.0 */
48 {11025,12000,8000,50000} /* MPEG 2.5 */
49 };
50
51 static const int mp3info_bitrate[2][3][14] = {
52 { /* MPEG 2.0 */
53 {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
54 {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
55 {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
56 },
57
58 { /* MPEG 1.0 */
59 {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
60 {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
61 {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
62 }
63 };
64
65 static const int frame_size_index[] = {24000, 72000, 72000};
66 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
67
68 #ifdef HAVE_ID3TAG
69
70 #include <id3tag.h>
71
72 static char *get_utf8(id3_ucs4_t const *string)
73 {
74 if (!string)
75 return NULL;
76 return (char *)id3_ucs4_utf8duplicate(string);
77 }
78
79 static char *get_stringlist(union id3_field *field)
80 {
81 unsigned int k, nstrings = id3_field_getnstrings(field);
82 char *result = NULL;
83
84 for (k = 0; k < nstrings; k++) {
85 char *tmp = (char *)get_utf8(id3_field_getstrings(field, k));
86 if (result) {
87 char *tmp2 = result;
88 result = make_message("%s %s", tmp2, tmp);
89 free(tmp);
90 free(tmp2);
91 } else
92 result = tmp;
93 }
94 return result;
95 }
96
97 static char *get_string(union id3_field *field)
98 {
99 id3_ucs4_t const *string = id3_field_getfullstring(field);
100
101 return get_utf8(string);
102 }
103
104 #define FOR_EACH_FIELD(f, j, fr) for (j = 0; j < (fr)->nfields && \
105 (f = id3_frame_field((fr), j)); j++)
106
107 static char *get_strings(struct id3_frame *fr)
108 {
109 int j;
110 union id3_field *field;
111
112 FOR_EACH_FIELD(field, j, fr) {
113 enum id3_field_type type = id3_field_type(field);
114
115 if (type == ID3_FIELD_TYPE_STRINGLIST)
116 return get_stringlist(field);
117 if (type == ID3_FIELD_TYPE_STRINGFULL)
118 return get_string(field);
119 }
120 return NULL;
121 }
122
123 /* this only sets values which are undefined so far */
124 static void parse_frames(struct id3_tag *id3_t, struct taginfo *tags)
125 {
126 int i;
127
128 for (i = 0; i < id3_t->nframes; i++) {
129 struct id3_frame *fr = id3_t->frames[i];
130 if (!strcmp(fr->id, ID3_FRAME_TITLE)) {
131 if (!tags->title)
132 tags->title = get_strings(fr);
133 continue;
134 }
135 if (!strcmp(fr->id, ID3_FRAME_ARTIST)) {
136 if (!tags->artist)
137 tags->artist = get_strings(fr);
138 continue;
139 }
140 if (!strcmp(fr->id, ID3_FRAME_ALBUM)) {
141 if (!tags->album)
142 tags->album = get_strings(fr);
143 continue;
144 }
145 if (!strcmp(fr->id, ID3_FRAME_YEAR)) {
146 if (!tags->year)
147 tags->year = get_strings(fr);
148 continue;
149 }
150 if (!strcmp(fr->id, ID3_FRAME_COMMENT)) {
151 if (!tags->comment)
152 tags->comment = get_strings(fr);
153 continue;
154 }
155 }
156 }
157
158 static int mp3_get_id3(unsigned char *map, size_t numbytes, __a_unused int fd,
159 struct taginfo *tags)
160 {
161 int ret = 0;
162 struct id3_tag *id3_t;
163
164 /* id3v2 tags are usually located at the beginning. */
165 id3_t = id3_tag_parse(map, numbytes);
166 if (id3_t) {
167 parse_frames(id3_t, tags);
168 ret |= 2;
169 id3_tag_delete(id3_t);
170 }
171 /* Also look for an id3v1 tag at the end of the file. */
172 if (numbytes >= 128) {
173 id3_t = id3_tag_parse(map + numbytes - 128, 128);
174 if (id3_t) {
175 parse_frames(id3_t, tags);
176 ret |= 1;
177 id3_tag_delete(id3_t);
178 }
179 }
180 return ret;
181 }
182
183 /* These helpers are not mentioned in the libid3tag header file. */
184 void id3_field_init(union id3_field *field, enum id3_field_type type);
185 void id3_field_finish(union id3_field *field);
186
187 /*
188 * Frames of type ID3_FRAME_COMMENT contain three fields of type language,
189 * string, and fullstring. The third field contains the actual comment.
190 */
191 static int set_comment_fields(struct id3_frame *fr, id3_ucs4_t *ucs4_val)
192 {
193 int ret;
194 union id3_field *field;
195
196 field = id3_frame_field(fr, 1);
197 id3_field_init(field, ID3_FIELD_TYPE_LANGUAGE);
198
199 field = id3_frame_field(fr, 2);
200 id3_field_init(field, ID3_FIELD_TYPE_STRING);
201
202 field = id3_frame_field(fr, 3);
203 id3_field_init(field, ID3_FIELD_TYPE_STRINGFULL);
204 ret = id3_field_setfullstring(field, ucs4_val);
205 if (ret < 0)
206 return -E_ID3_SETSTRING;
207 return 1;
208 }
209
210 /*
211 * UCS-4 stands for Universal Character Set where each character uses exactly
212 * 32 bits. It is also known as UTF-32, see ISO 10646.
213 *
214 * We have to use UCS-4 as an intermediate representation because the functions
215 * of libid3tag which set the tag content expect an array of UCS-4 characters.
216 * Fortunately, libid3tag contains conversion functions from and to UTF-8.
217 */
218 static int replace_tag(char const *id, const char *val, struct id3_tag *id3_t,
219 int options)
220 {
221 int ret;
222 struct id3_frame *fr;
223 union id3_field *field;
224 id3_ucs4_t *ucs4_val;
225
226 /* First, detach all frames that match the given id. */
227 while ((fr = id3_tag_findframe(id3_t, id, 0))) {
228 PARA_INFO_LOG("deleting %s frame\n", id);
229 ret = id3_tag_detachframe(id3_t, fr);
230 if (ret < 0)
231 return -E_ID3_DETACH;
232 id3_frame_delete(fr);
233 }
234 if (!val || !*val)
235 return 0;
236 fr = id3_frame_new(id);
237 PARA_DEBUG_LOG("frame desc: %s, %u fields\n", fr->description, fr->nfields);
238
239 /* Frame 0 contains the encoding. We always use UTF-8. */
240 field = id3_frame_field(fr, 0);
241 id3_field_init(field, ID3_FIELD_TYPE_TEXTENCODING);
242 ret = id3_field_settextencoding(field, ID3_FIELD_TEXTENCODING_UTF_8);
243 if (ret < 0)
244 return -E_ID3_SETENCODING;
245 /* create UCS-4 representation */
246 ucs4_val = id3_utf8_ucs4duplicate((const id3_utf8_t *)val);
247
248 if (strcmp(id, ID3_FRAME_COMMENT) == 0)
249 ret = set_comment_fields(fr, ucs4_val);
250 else {
251 /* Non-comment frames contain the value in field 1. */
252 field = id3_frame_field(fr, 1);
253 if (options & ID3_TAG_OPTION_ID3V1) {
254 id3_ucs4_t *ptr[] = {ucs4_val, NULL};
255 id3_field_init(field, ID3_FIELD_TYPE_STRINGLIST);
256 ret = id3_field_setstrings(field, 1, ptr);
257 } else {
258 id3_field_init(field, ID3_FIELD_TYPE_STRINGFULL);
259 ret = id3_field_setfullstring(field, ucs4_val);
260 }
261 }
262 free(ucs4_val);
263 if (ret < 0)
264 return -E_ID3_SETSTRING;
265
266 PARA_INFO_LOG("attaching %s frame, value: %s\n", id, val);
267 ret = id3_tag_attachframe(id3_t, fr);
268 if (ret < 0)
269 return -E_ID3_ATTACH;
270 return 1;
271 }
272
273 static int replace_tags(struct id3_tag *id3_t, struct taginfo *tags)
274 {
275 int ret, options = id3_tag_options(id3_t, 0, 0);
276
277 ret = replace_tag(ID3_FRAME_ARTIST, tags->artist, id3_t, options);
278 if (ret < 0)
279 return ret;
280 ret = replace_tag(ID3_FRAME_TITLE, tags->title, id3_t, options);
281 if (ret < 0)
282 return ret;
283 ret = replace_tag(ID3_FRAME_ALBUM, tags->album, id3_t, options);
284 if (ret < 0)
285 return ret;
286 ret = replace_tag(ID3_FRAME_YEAR, tags->year, id3_t, options);
287 if (ret < 0)
288 return ret;
289 ret = replace_tag(ID3_FRAME_COMMENT, tags->comment, id3_t, options);
290 if (ret < 0)
291 return ret;
292 return 1;
293 }
294
295 /* id3_tag_delete() does not seem to work due to refcount issues. */
296 static void free_tag(struct id3_tag *id3_t)
297 {
298 int i, j;
299
300 if (!id3_t)
301 return;
302 for (i = 0; i < id3_t->nframes; i++) {
303 struct id3_frame *fr = id3_t->frames[i];
304 for (j = 0; j < fr->nfields; j++) {
305 union id3_field *field = &fr->fields[j];
306 id3_field_finish(field);
307 }
308 free(fr);
309 }
310 free(id3_t->frames);
311 free(id3_t);
312 }
313
314 static int mp3_rewrite_tags(const char *map, size_t mapsize,
315 struct taginfo *tags, int fd, __a_unused const char *filename)
316 {
317 int ret;
318 id3_length_t old_v2size, new_v2size;
319 id3_byte_t v1_buffer[128], *v2_buffer;
320 size_t data_sz;
321 struct id3_tag *v1_tag = NULL, *v2_tag = NULL;
322
323 if (mapsize >= 128) {
324 v1_tag = id3_tag_parse((const id3_byte_t *)map + mapsize - 128,
325 128);
326 if (v1_tag) {
327 PARA_NOTICE_LOG("replacing id3v1 tag\n");
328 ret = replace_tags(v1_tag, tags);
329 if (ret < 0)
330 goto out;
331 id3_tag_render(v1_tag, v1_buffer);
332 }
333 }
334 old_v2size = 0;
335 v2_tag = id3_tag_parse((const id3_byte_t *)map, mapsize);
336 if (v2_tag) {
337 PARA_NOTICE_LOG("replacing id3v2 tag\n");
338 old_v2size = v2_tag->paddedsize;
339 } else {
340 PARA_NOTICE_LOG("adding id3v2 tag\n");
341 v2_tag = id3_tag_new();
342 assert(v2_tag);
343 }
344 /*
345 * Turn off all options to avoid creating an extended header. id321
346 * does not understand it.
347 */
348 id3_tag_options(v2_tag, ~0U, 0);
349 ret = replace_tags(v2_tag, tags);
350 if (ret < 0)
351 goto out;
352 new_v2size = id3_tag_render(v2_tag, NULL);
353 v2_buffer = para_malloc(new_v2size);
354 id3_tag_render(v2_tag, v2_buffer);
355 PARA_INFO_LOG("writing v2 tag (%lu bytes)\n", new_v2size);
356 ret = write_all(fd, (char *)v2_buffer, new_v2size);
357 free(v2_buffer);
358 if (ret < 0)
359 goto out;
360 data_sz = mapsize - old_v2size;
361 if (v1_tag && data_sz >= 128)
362 data_sz -= 128;
363 PARA_INFO_LOG("writing data part (%zu bytes)\n", data_sz);
364 ret = write_all(fd, map + old_v2size, data_sz);
365 if (ret < 0)
366 goto out;
367 if (v1_tag) {
368 PARA_INFO_LOG("writing v1 tag\n");
369 ret = write_all(fd, (char *)v1_buffer, 128);
370 }
371 out:
372 free_tag(v1_tag);
373 free_tag(v2_tag);
374 return ret;
375 }
376
377 #else /* HAVE_ID3TAG */
378
379 /*
380 * Remove trailing whitespace from the end of a string
381 */
382 static char *unpad(char *string)
383 {
384 char *pos = string + strlen(string) - 1;
385 while (para_isspace(pos[0]))
386 (pos--)[0] = 0;
387 return string;
388 }
389
390 static int mp3_get_id3(unsigned char *map, size_t numbytes, __a_unused int fd,
391 struct taginfo *tags)
392 {
393 char title[31], artist[31], album[31], year[5], comment[31];
394 off_t fpos;
395
396 if (numbytes < 128 || strncmp("TAG", (char *)map + numbytes - 128, 3)) {
397 PARA_DEBUG_LOG("no id3 v1 tag\n");
398 return 0;
399 }
400 fpos = numbytes - 125;
401 memcpy(title, map + fpos, 30);
402 fpos += 30;
403 title[30] = '\0';
404 memcpy(artist, map + fpos, 30);
405 fpos += 30;
406 artist[30] = '\0';
407 memcpy(album, map + fpos, 30);
408 fpos += 30;
409 album[30] = '\0';
410 memcpy(year, map + fpos, 4);
411 fpos += 4;
412 year[4] = '\0';
413 memcpy(comment, map + fpos, 30);
414 comment[30] = '\0';
415 unpad(title);
416 unpad(artist);
417 unpad(album);
418 unpad(year);
419 unpad(comment);
420 tags->artist = para_strdup(artist);
421 tags->title = para_strdup(title);
422 tags->year = para_strdup(year);
423 tags->album = para_strdup(album);
424 tags->comment = para_strdup(comment);
425 return 1;
426 }
427 #endif /* HAVE_ID3TAG */
428
429 static int header_frequency(struct mp3header *h)
430 {
431 if (h->version > 2 || h->freq > 3)
432 return -E_HEADER_FREQ;
433 return frequencies[h->version][h->freq];
434 }
435
436 static const char *header_mode(struct mp3header *h)
437 {
438 if (h->mode > 4)
439 h->mode = 4; /* invalid */
440 return mode_text[h->mode];
441 }
442
443 static int header_channels(struct mp3header *h)
444 {
445 if (h->mode > 3)
446 return 0;
447 if (h->mode < 3)
448 return 2;
449 return 1;
450 }
451
452 static int header_bitrate(struct mp3header *h)
453 {
454 if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
455 return -E_HEADER_BITRATE;
456 return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
457 }
458
459 static int frame_length(struct mp3header *header)
460 {
461 int hb, hf = header_frequency(header);
462
463 if (hf < 0)
464 return hf;
465 hb = header_bitrate(header);
466 if (hb < 0)
467 return hb;
468 if (header->sync != 0xFFE || header->layer > 3)
469 return -E_FRAME;
470 return frame_size_index[3 - header->layer] *
471 ((header->version & 1) + 1) * hb / hf
472 + header->padding;
473 }
474
475 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
476 {
477 if ((*(unsigned int*)h1) == (*(unsigned int*)h2))
478 return 1;
479 if ((h1->version == h2->version) &&
480 (h1->layer == h2->layer) &&
481 (h1->crc == h2->crc) &&
482 (h1->freq == h2->freq) &&
483 (h1->mode == h2->mode) &&
484 (h1->copyright == h2->copyright) &&
485 (h1->original == h2->original) &&
486 (h1->emphasis == h2->emphasis))
487 return 1;
488 return 0;
489 }
490
491 /*
492 * get next MP3 frame header.
493 *
494 * On success, the header frame length is returned and the given header
495 * structure that is filled in. A return value of zero means that we did not
496 * retrieve a valid frame header, and a negative return value indicates an
497 * error.
498 */
499 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
500 struct mp3header *header)
501 {
502 int fl, ret;
503
504 if (*fpos + FRAME_HEADER_SIZE > numbytes) {
505 *fpos = numbytes - 1;
506 header->sync = 0;
507 return 0;
508 }
509 header->layer = (map[*fpos + 1] >> 1) & 3;
510 header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
511 if (map[*fpos + 1] & 0x10)
512 header->version = (map[*fpos + 1] >> 3) & 1;
513 else
514 header->version = 2;
515 if ((header->sync != 0xFFE) || (header->layer != 1)) {
516 ret = 0;
517 header->sync = 0;
518 goto out;
519 }
520 header->crc = map[*fpos + 1] & 1;
521 header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
522 header->freq = (map[*fpos + 2] >> 2) & 0x3;
523 header->padding = (map[*fpos + 2] >>1) & 0x1;
524 header->mode = (map[*fpos + 3] >> 6) & 0x3;
525 fl = frame_length(header);
526 ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
527 out:
528 *fpos += FRAME_HEADER_SIZE;
529 return ret;
530 }
531
532 /*
533 * find the next mp3 header
534 *
535 * Return the length of the next frame header or zero if the end of the file is
536 * reached.
537 */
538 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
539 struct mp3header *result)
540 {
541 int k, l = 0, first_len;
542 struct mp3header h, h2;
543 long valid_start = 0;
544
545 for (; *fpos < numbytes; (*fpos)++) {
546 if (map[*fpos] != 0xff)
547 continue;
548 valid_start = *fpos;
549 first_len = get_header(map, numbytes, fpos, &h);
550 if (first_len <= 0)
551 continue;
552 *fpos += first_len - FRAME_HEADER_SIZE;
553 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
554 if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
555 break;
556 if (!compare_headers(&h, &h2))
557 break;
558 *fpos += l - FRAME_HEADER_SIZE;
559 }
560 if (k == MIN_CONSEC_GOOD_FRAMES) {
561 *fpos = valid_start;
562 *result = h2;
563 return first_len;
564 }
565 }
566 return 0;
567 }
568
569 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
570 struct mp3header *header)
571 {
572 int frame_len;
573
574 frame_len = get_header(map, numbytes, fpos, header);
575 if (frame_len < 0)
576 return frame_len;
577 if (!frame_len) {
578 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
579 if (frame_len <= 0)
580 return frame_len;
581 } else
582 *fpos -= FRAME_HEADER_SIZE;
583 if (frame_len <= 1)
584 return -E_FRAME_LENGTH;
585 return frame_len;
586 }
587
588 static int mp3_read_info(unsigned char *map, size_t numbytes, int fd,
589 struct afh_info *afhi)
590 {
591 uint64_t freq_sum = 0, br_sum = 0;
592 int fl = 0, ret, len = 0, old_br = -1, vbr = 0;
593 struct timeval total_time = {0, 0};
594 unsigned chunk_table_size = 1000; /* gets increased on demand */
595 off_t fpos = 0;
596 struct mp3header header;
597 const char *tag_versions[] = {"no", "id3v1", "id3v2", "id3v1+id3v2"};
598
599 afhi->chunks_total = 0;
600 afhi->chunk_table = para_malloc(chunk_table_size * sizeof(uint32_t));
601 while (1) {
602 int freq, br;
603 struct timeval tmp, cct; /* current chunk time */
604 fpos += len;
605 len = find_valid_start(map, numbytes, &fpos, &header);
606 if (len <= 0) {
607 size_t end;
608 ret = -E_MP3_INFO;
609 if (!afhi->chunks_total)
610 goto err_out;
611 end = afhi->chunk_table[afhi->chunks_total - 1] + fl;
612 afhi->chunk_table[afhi->chunks_total]
613 = PARA_MIN(end, numbytes);
614 break;
615 }
616 ret = header_frequency(&header);
617 if (ret < 0)
618 continue;
619 freq = ret;
620 ret = header_bitrate(&header);
621 if (ret < 0)
622 continue;
623 br = ret;
624 ret = frame_length(&header);
625 if (ret < 0)
626 continue;
627 fl = ret;
628 tmp.tv_sec = fl - header.padding;
629 tmp.tv_usec = 0;
630 tv_divide(br * 125, &tmp, &cct);
631 tv_add(&cct, &total_time, &tmp);
632 total_time = tmp;
633 if (afhi->chunks_total >= chunk_table_size) {
634 chunk_table_size *= 2;
635 afhi->chunk_table = para_realloc(afhi->chunk_table,
636 chunk_table_size * sizeof(uint32_t));
637 }
638 afhi->chunk_table[afhi->chunks_total] = fpos;
639 afhi->chunks_total++;
640 freq_sum += freq;
641 br_sum += br;
642 if (afhi->chunks_total != 1 && old_br != br)
643 vbr = 1;
644 old_br = br;
645 }
646 ret = -E_MP3_INFO;
647 if (!freq_sum || !br_sum)
648 goto err_out;
649 afhi->bitrate = br_sum / afhi->chunks_total;
650 afhi->frequency = freq_sum / afhi->chunks_total;
651 afhi->channels = header_channels(&header);
652 afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
653 tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
654 PARA_DEBUG_LOG("%" PRIu32 "chunks, each %lums\n", afhi->chunks_total,
655 tv2ms(&afhi->chunk_tv));
656 set_max_chunk_size(afhi);
657 ret = mp3_get_id3(map, numbytes, fd, &afhi->tags);
658 afhi->techinfo = make_message("%cbr, %s, %s tags", vbr? 'v' : 'c',
659 header_mode(&header), tag_versions[ret]);
660 return 1;
661 err_out:
662 free(afhi->chunk_table);
663 return ret;
664 }
665
666 /*
667 * Read mp3 information from audio file
668 */
669 static int mp3_get_file_info(char *map, size_t numbytes, int fd,
670 struct afh_info *afhi)
671 {
672 int ret;
673
674 ret = mp3_read_info((unsigned char *)map, numbytes, fd, afhi);
675 if (ret < 0)
676 return ret;
677 if (afhi->seconds_total < 2 || !afhi->chunks_total)
678 return -E_MP3_INFO;
679 return 1;
680 }
681
682 static const char * const mp3_suffixes[] = {"mp3", NULL};
683
684 /**
685 * the init function of the mp3 audio format handler
686 *
687 * \param afh pointer to the struct to initialize
688 */
689 void mp3_afh_init(struct audio_format_handler *afh)
690 {
691 afh->get_file_info = mp3_get_file_info;
692 afh->suffixes = mp3_suffixes;
693 #ifdef HAVE_LIBID3TAG
694 afh->rewrite_tags = mp3_rewrite_tags;
695 #endif /* HAVE_LIBID3TAG */
696 }