mp3_afh.c

   1 /*
   2  * Copyright (C) 2003-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file mp3_afh.c para_server's mp3 audio format handler */
   8
   9 /*
  10  * This file is based in part on mp3tech.c and mp3tech.h, Copyright (C)
  11  * 2000-2001 Cedric Tefft <cedric@earthling.net>, which in turn is based
  12  * in part on
  13  *
  14  *      * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
  15  *      * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and
  16  *                       Johannes Overmann <overmann@iname.com>
  17  */
  18
  19 #include <osl.h>
  20 #include "para.h"
  21 #include "error.h"
  22 #include "afh.h"
  23 #include "string.h"
  24
  25 /** \cond some defines and structs which are only used in this file */
  26
  27 /*
  28  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  29  * to see before we decide we are looking at a real MP3 file
  30  */
  31 #define MIN_CONSEC_GOOD_FRAMES 4
  32 #define FRAME_HEADER_SIZE 4
  33 #define MIN_FRAME_SIZE 21
  34
  35 struct mp3header {
  36         unsigned long sync;
  37         unsigned int version;
  38         unsigned int layer;
  39         unsigned int crc;
  40         unsigned int bitrate;
  41         unsigned int freq;
  42         unsigned int padding;
  43         unsigned int mode;
  44         unsigned int copyright;
  45         unsigned int original;
  46         unsigned int emphasis;
  47 };
  48
  49 /** \endcond */
  50 static const int frequencies[3][4] = {
  51         {22050,24000,16000,50000}, /* MPEG 2.0 */
  52         {44100,48000,32000,50000}, /* MPEG 1.0 */
  53         {11025,12000,8000,50000} /* MPEG 2.5 */
  54 };
  55
  56 static const int mp3info_bitrate[2][3][14] = {
  57 { /* MPEG 2.0 */
  58         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  59         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  60         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  61 },
  62
  63 { /* MPEG 1.0 */
  64         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  65         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  66         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  67 }
  68 };
  69
  70 static const int frame_size_index[] = {24000, 72000, 72000};
  71 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  72
  73 #ifdef HAVE_LIBID3TAG
  74
  75 #include <id3tag.h>
  76
  77 static char *get_latin1(id3_ucs4_t const *string)
  78 {
  79         if (!string)
  80                 return NULL;
  81         return (char *)id3_ucs4_latin1duplicate(string);
  82 }
  83
  84 static char *get_stringlist(union id3_field *field)
  85 {
  86         unsigned int k, nstrings = id3_field_getnstrings(field);
  87         char *result = NULL;
  88
  89         for (k = 0; k < nstrings; k++) {
  90                 char *tmp = (char *)get_latin1(id3_field_getstrings(field, k));
  91                 if (result) {
  92                         char *tmp2 = result;
  93                         result = make_message("%s %s", tmp2, tmp);
  94                         free(tmp);
  95                         free(tmp2);
  96                 } else
  97                         result = tmp;
  98         }
  99         return result;
 100 }
 101
 102 static char *get_string(union id3_field *field)
 103 {
 104         id3_ucs4_t const *string = id3_field_getfullstring(field);
 105
 106         return get_latin1(string);
 107 }
 108
 109 #define FOR_EACH_FIELD(f, j, fr) for (j = 0; j < (fr)->nfields && \
 110         (f = id3_frame_field((fr), j)); j++)
 111
 112 static char *get_strings(struct id3_frame *fr)
 113 {
 114         int j;
 115         union id3_field *field;
 116
 117         FOR_EACH_FIELD(field, j, fr) {
 118                 enum id3_field_type type = id3_field_type(field);
 119
 120                 if (type == ID3_FIELD_TYPE_STRINGLIST)
 121                         return get_stringlist(field);
 122                 if (type == ID3_FIELD_TYPE_STRINGFULL)
 123                         return get_string(field);
 124         }
 125         return NULL;
 126 }
 127
 128 static void mp3_get_id3(__a_unused unsigned char *map,
 129                 __a_unused size_t numbytes, int fd, struct taginfo *tags)
 130 {
 131         int i;
 132         struct id3_tag *id3_t;
 133         struct id3_file *id3_f = id3_file_fdopen(fd, ID3_FILE_MODE_READONLY);
 134
 135         if (!id3_f)
 136                 return;
 137         id3_t = id3_file_tag(id3_f);
 138         if (!id3_t) {
 139                 id3_file_close(id3_f);
 140                 return;
 141         }
 142         for (i = 0; i < id3_t->nframes; i++) {
 143                 struct id3_frame *fr = id3_t->frames[i];
 144                 if (!strcmp(fr->id, "TIT2")) {
 145                         if (!tags->title)
 146                                 tags->title = get_strings(fr);
 147                         continue;
 148                 }
 149                 if (!strcmp(fr->id, "TPE1")) {
 150                         if (!tags->artist)
 151                                 tags->artist = get_strings(fr);
 152                         continue;
 153                 }
 154                 if (!strcmp(fr->id, "TALB")) {
 155                         if (!tags->album)
 156                                 tags->album = get_strings(fr);
 157                         continue;
 158                 }
 159                 if (!strcmp(fr->id, "TDRC")) {
 160                         if (!tags->year)
 161                                 tags->year = get_strings(fr);
 162                         continue;
 163                 }
 164                 if (!strcmp(fr->id, "COMM")) {
 165                         if (!tags->comment)
 166                                 tags->comment = get_strings(fr);
 167                         continue;
 168                 }
 169         }
 170         id3_file_close(id3_f);
 171 }
 172
 173 #else /* HAVE_LIBID3TAG */
 174
 175 /*
 176  * Remove trailing whitespace from the end of a string
 177  */
 178 static char *unpad(char *string)
 179 {
 180         char *pos = string + strlen(string) - 1;
 181         while (para_isspace(pos[0]))
 182                 (pos--)[0] = 0;
 183         return string;
 184 }
 185
 186 static void mp3_get_id3(unsigned char *map, size_t numbytes, __a_unused int fd,
 187         struct taginfo *tags)
 188 {
 189         char title[31], artist[31], album[31], year[5], comment[31];
 190         off_t fpos;
 191
 192         if (numbytes < 128 || strncmp("TAG", (char *)map + numbytes - 128, 3)) {
 193                 PARA_DEBUG_LOG("no id3 v1 tag\n");
 194                 return;
 195         }
 196         fpos = numbytes - 125;
 197         memcpy(title, map + fpos, 30);
 198         fpos += 30;
 199         title[30] = '\0';
 200         memcpy(artist, map + fpos, 30);
 201         fpos += 30;
 202         artist[30] = '\0';
 203         memcpy(album, map + fpos, 30);
 204         fpos += 30;
 205         album[30] = '\0';
 206         memcpy(year, map + fpos, 4);
 207         fpos += 4;
 208         year[4] = '\0';
 209         memcpy(comment, map + fpos, 30);
 210         comment[30] = '\0';
 211         unpad(title);
 212         unpad(artist);
 213         unpad(album);
 214         unpad(year);
 215         unpad(comment);
 216         tags->artist = para_strdup(artist);
 217         tags->title = para_strdup(title);
 218         tags->year = para_strdup(year);
 219         tags->album = para_strdup(album);
 220         tags->comment = para_strdup(comment);
 221 }
 222 #endif /* HAVE_LIBID3TAG */
 223
 224 static int header_frequency(struct mp3header *h)
 225 {
 226         if (h->version > 2 || h->freq > 3)
 227                 return -E_HEADER_FREQ;
 228         return frequencies[h->version][h->freq];
 229 }
 230
 231 static const char *header_mode(struct mp3header *h)
 232 {
 233         if (h->mode > 4)
 234                 h->mode = 4; /* invalid */
 235         return mode_text[h->mode];
 236 }
 237
 238 static int header_channels(struct mp3header *h)
 239 {
 240         if (h->mode > 3)
 241                 return 0;
 242         if (h->mode < 3)
 243                 return 2;
 244         return 1;
 245 }
 246
 247 static int header_bitrate(struct mp3header *h)
 248 {
 249         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 250                 return -E_HEADER_BITRATE;
 251         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 252 }
 253
 254 static int frame_length(struct mp3header *header)
 255 {
 256         int hb, hf = header_frequency(header);
 257
 258         if (hf < 0)
 259                 return hf;
 260         hb = header_bitrate(header);
 261         if (hb < 0)
 262                 return hb;
 263         if (header->sync != 0xFFE || header->layer > 3)
 264                 return -E_FRAME;
 265         return frame_size_index[3 - header->layer] *
 266                 ((header->version & 1) + 1) * hb / hf
 267                 + header->padding;
 268 }
 269
 270 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 271 {
 272         if ((*(unsigned int*)h1) == (*(unsigned int*)h2))
 273                 return 1;
 274         if ((h1->version == h2->version) &&
 275                         (h1->layer == h2->layer) &&
 276                         (h1->crc == h2->crc) &&
 277                         (h1->freq == h2->freq) &&
 278                         (h1->mode == h2->mode) &&
 279                         (h1->copyright == h2->copyright) &&
 280                         (h1->original == h2->original) &&
 281                         (h1->emphasis == h2->emphasis))
 282                 return 1;
 283         return 0;
 284 }
 285
 286 /*
 287  * get next MP3 frame header.
 288  *
 289  * On success, the header frame length is returned and the given header
 290  * structure that is filled in.  A return value of zero means that we did not
 291  * retrieve a valid frame header, and a negative return value indicates an
 292  * error.
 293  */
 294 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 295         struct mp3header *header)
 296 {
 297         int fl, ret;
 298
 299         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 300                 *fpos = numbytes - 1;
 301                 header->sync = 0;
 302                 return 0;
 303         }
 304         header->layer = (map[*fpos + 1] >> 1) & 3;
 305         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 306         if (map[*fpos + 1] & 0x10)
 307                 header->version = (map[*fpos + 1] >> 3) & 1;
 308         else
 309                 header->version = 2;
 310         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 311                 ret = 0;
 312                 header->sync = 0;
 313                 goto out;
 314         }
 315         header->crc = map[*fpos + 1] & 1;
 316         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 317         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 318         header->padding = (map[*fpos + 2] >>1) & 0x1;
 319         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 320         fl = frame_length(header);
 321         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 322 out:
 323         *fpos += FRAME_HEADER_SIZE;
 324         return ret;
 325 }
 326
 327 /*
 328  * find the next mp3 header
 329  *
 330  * Return the length of the next frame header or zero if the end of the file is
 331  * reached.
 332  */
 333 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
 334         struct mp3header *result)
 335 {
 336         int k, l = 0, first_len;
 337         struct mp3header h, h2;
 338         long valid_start = 0;
 339
 340         for (; *fpos < numbytes; (*fpos)++) {
 341                 if (map[*fpos] != 0xff)
 342                         continue;
 343                 valid_start = *fpos;
 344                 first_len = get_header(map, numbytes, fpos, &h);
 345                 if (first_len <= 0)
 346                         continue;
 347                 *fpos += first_len - FRAME_HEADER_SIZE;
 348                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 349                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 350                                 break;
 351                         if (!compare_headers(&h, &h2))
 352                                 break;
 353                         *fpos += l - FRAME_HEADER_SIZE;
 354                 }
 355                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 356                         *fpos = valid_start;
 357                         *result = h2;
 358                         return first_len;
 359                 }
 360         }
 361         return 0;
 362 }
 363
 364 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
 365         struct mp3header *header)
 366 {
 367         int frame_len;
 368
 369         frame_len = get_header(map, numbytes, fpos, header);
 370         if (frame_len < 0)
 371                 return frame_len;
 372         if (!frame_len) {
 373                 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
 374                 if (frame_len <= 0)
 375                         return frame_len;
 376         } else
 377                 *fpos -= FRAME_HEADER_SIZE;
 378         if (frame_len <= 1)
 379                 return -E_FRAME_LENGTH;
 380         return frame_len;
 381 }
 382
 383 static int mp3_read_info(unsigned char *map, size_t numbytes, int fd,
 384                 struct afh_info *afhi)
 385 {
 386         uint64_t freq_sum = 0, br_sum = 0;
 387         int fl = 0, ret, len = 0, old_br = -1, vbr = 0;
 388         struct timeval total_time = {0, 0};
 389         unsigned chunk_table_size = 1000; /* gets increased on demand */
 390         off_t fpos = 0;
 391         struct mp3header header;
 392
 393         afhi->chunks_total = 0;
 394         afhi->chunk_table = para_malloc(chunk_table_size * sizeof(uint32_t));
 395         while (1) {
 396                 int freq, br;
 397                 struct timeval tmp, cct; /* current chunk time */
 398                 fpos += len;
 399                 len = find_valid_start(map, numbytes, &fpos, &header);
 400                 if (len <= 0) {
 401                         size_t end;
 402                         ret = -E_MP3_INFO;
 403                         if (!afhi->chunks_total)
 404                                 goto err_out;
 405                         end = afhi->chunk_table[afhi->chunks_total - 1] + fl;
 406                         afhi->chunk_table[afhi->chunks_total]
 407                                 = PARA_MIN(end, numbytes);
 408                         break;
 409                 }
 410                 ret = header_frequency(&header);
 411                 if (ret < 0)
 412                         continue;
 413                 freq = ret;
 414                 ret = header_bitrate(&header);
 415                 if (ret < 0)
 416                         continue;
 417                 br = ret;
 418                 ret = frame_length(&header);
 419                 if (ret < 0)
 420                         continue;
 421                 fl = ret;
 422                 tmp.tv_sec = fl;
 423                 tmp.tv_usec = 0;
 424                 tv_divide(br * 125, &tmp, &cct);
 425                 tv_add(&cct, &total_time, &tmp);
 426                 total_time = tmp;
 427                 if (afhi->chunks_total >= chunk_table_size) {
 428                         chunk_table_size *= 2;
 429                         afhi->chunk_table = para_realloc(afhi->chunk_table,
 430                                 chunk_table_size * sizeof(uint32_t));
 431                 }
 432                 afhi->chunk_table[afhi->chunks_total] = fpos;
 433                 afhi->chunks_total++;
 434                 freq_sum += freq;
 435                 br_sum += br;
 436                 if (afhi->chunks_total != 1 && old_br != br)
 437                         vbr = 1;
 438                 old_br = br;
 439         }
 440         ret = -E_MP3_INFO;
 441         if (!freq_sum || !br_sum)
 442                 goto err_out;
 443         afhi->bitrate = br_sum / afhi->chunks_total;
 444         afhi->frequency = freq_sum / afhi->chunks_total;
 445         afhi->channels = header_channels(&header);
 446         afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 447         tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
 448         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
 449                 tv2ms(&afhi->chunk_tv));
 450         afhi->techinfo = make_message("%cbr, %s", vbr? 'v' : 'c',
 451                 header_mode(&header));
 452         mp3_get_id3(map, numbytes, fd, &afhi->tags);
 453         return 1;
 454 err_out:
 455         PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 456         free(afhi->chunk_table);
 457         return ret;
 458 }
 459
 460 /*
 461  * Read mp3 information from audio file
 462  */
 463 static int mp3_get_file_info(char *map, size_t numbytes, int fd,
 464                 struct afh_info *afhi)
 465 {
 466         int ret;
 467
 468         ret = mp3_read_info((unsigned char *)map, numbytes, fd, afhi);
 469         if (ret < 0)
 470                 return ret;
 471         if (afhi->seconds_total < 2 || !afhi->chunks_total)
 472                 return -E_MP3_INFO;
 473         return 1;
 474 }
 475
 476 static const char* mp3_suffixes[] = {"mp3", NULL};
 477
 478 /**
 479  * the init function of the mp3 audio format handler
 480  *
 481  * \param afh pointer to the struct to initialize
 482  */
 483 void mp3_init(struct audio_format_handler *afh)
 484 {
 485         afh->get_file_info = mp3_get_file_info;
 486         afh->suffixes = mp3_suffixes;
 487 }