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 "para.h"
  20 #include "error.h"
  21 #include "afh.h"
  22 #include "string.h"
  23 #include "afs.h"
  24 #include "server.h"
  25
  26 /** \cond some defines and structs which are only used in this file */
  27
  28 /*
  29  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  30  * to see before we decide we are looking at a real MP3 file
  31  */
  32 #define MIN_CONSEC_GOOD_FRAMES 4
  33 #define FRAME_HEADER_SIZE 4
  34 #define MIN_FRAME_SIZE 21
  35
  36 struct mp3header {
  37         unsigned long sync;
  38         unsigned int version;
  39         unsigned int layer;
  40         unsigned int crc;
  41         unsigned int bitrate;
  42         unsigned int freq;
  43         unsigned int padding;
  44         unsigned int mode;
  45         unsigned int copyright;
  46         unsigned int original;
  47         unsigned int emphasis;
  48 };
  49
  50 /** \endcond */
  51 static const int frequencies[3][4] = {
  52         {22050,24000,16000,50000}, /* MPEG 2.0 */
  53         {44100,48000,32000,50000}, /* MPEG 1.0 */
  54         {11025,12000,8000,50000} /* MPEG 2.5 */
  55 };
  56
  57 static const int mp3info_bitrate[2][3][14] = {
  58 { /* MPEG 2.0 */
  59         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  60         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  61         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  62 },
  63
  64 { /* MPEG 1.0 */
  65         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  66         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  67         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  68 }
  69 };
  70
  71 static const int frame_size_index[] = {24000, 72000, 72000};
  72 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  73
  74 #ifdef HAVE_LIBID3TAG
  75
  76 #include <id3tag.h>
  77
  78 static char *get_latin1(id3_ucs4_t const *string)
  79 {
  80         if (!string)
  81                 return NULL;
  82         return (char *)id3_ucs4_latin1duplicate(string);
  83 }
  84
  85 static char *get_stringlist(union id3_field *field)
  86 {
  87         unsigned int k, nstrings = id3_field_getnstrings(field);
  88         char *result = NULL;
  89
  90         for (k = 0; k < nstrings; k++) {
  91                 char *tmp = (char *)get_latin1(id3_field_getstrings(field, k));
  92                 if (result) {
  93                         char *tmp2 = result;
  94                         result = make_message("%s %s", tmp2, tmp);
  95                         free(tmp);
  96                         free(tmp2);
  97                 } else
  98                         result = tmp;
  99         }
 100         return result;
 101 }
 102
 103 static char *get_string(union id3_field *field)
 104 {
 105         id3_ucs4_t const *string = id3_field_getfullstring(field);
 106
 107         return get_latin1(string);
 108 }
 109
 110 #define FOR_EACH_FIELD(f, j, fr) for (j = 0; j < (fr)->nfields && \
 111         (f = id3_frame_field((fr), j)); j++)
 112
 113 static char *get_strings(struct id3_frame *fr)
 114 {
 115         int j;
 116         union id3_field *field;
 117
 118         FOR_EACH_FIELD(field, j, fr) {
 119                 enum id3_field_type type = id3_field_type(field);
 120
 121                 if (type == ID3_FIELD_TYPE_STRINGLIST)
 122                         return get_stringlist(field);
 123                 if (type == ID3_FIELD_TYPE_STRINGFULL)
 124                         return get_string(field);
 125         }
 126         return NULL;
 127 }
 128
 129 static char *mp3_get_id3(__a_unused unsigned char *map,
 130                 __a_unused size_t numbytes, int fd)
 131 {
 132         int i;
 133         struct id3_tag *id3_t;
 134         char *title = NULL, *artist = NULL, *album = NULL, *year = NULL,
 135                 *comment = NULL, *result;
 136         struct id3_file *id3_f = id3_file_fdopen(fd, ID3_FILE_MODE_READONLY);
 137
 138         if (!id3_f)
 139                 goto no_tag;
 140         id3_t = id3_file_tag(id3_f);
 141         if (!id3_t)
 142                 goto no_tag;
 143         for (i = 0; i < id3_t->nframes; i++) {
 144                 struct id3_frame *fr = id3_t->frames[i];
 145                 if (!strcmp(fr->id, "TIT2")) {
 146                         if (!title)
 147                                 title = get_strings(fr);
 148                         continue;
 149                 }
 150                 if (!strcmp(fr->id, "TPE1")) {
 151                         if (!artist)
 152                                 artist = get_strings(fr);
 153                         continue;
 154                 }
 155                 if (!strcmp(fr->id, "TALB")) {
 156                         if (!album)
 157                                 album = get_strings(fr);
 158                         continue;
 159                 }
 160                 if (!strcmp(fr->id, "TDRC")) {
 161                         if (!year)
 162                                 year = get_strings(fr);
 163                         continue;
 164                 }
 165                 if (!strcmp(fr->id, "COMM")) {
 166                         if (!comment)
 167                                 comment = get_strings(fr);
 168                         continue;
 169                 }
 170         }
 171         id3_file_close(id3_f);
 172         result = make_taginfo(title, artist, album, year, comment);
 173         free(title);
 174         free(artist);
 175         free(album);
 176         free(year);
 177         free(comment);
 178         return result;
 179 no_tag:
 180         if (id3_f)
 181                 id3_file_close(id3_f);
 182         return make_message("%s: (no id3 v1/v2 tag)\n%s:\n",
 183                 status_item_list[SI_TAGINFO1],
 184                 status_item_list[SI_TAGINFO2]);
 185 }
 186
 187 #else /* HAVE_LIBID3TAG */
 188
 189 /*
 190  * Remove trailing whitespace from the end of a string
 191  */
 192 static char *unpad(char *string)
 193 {
 194         char *pos = string + strlen(string) - 1;
 195         while (para_isspace(pos[0]))
 196                 (pos--)[0] = 0;
 197         return string;
 198 }
 199
 200 static char *mp3_get_id3(unsigned char *map, size_t numbytes, __a_unused int fd)
 201 {
 202         char title[31], artist[31], album[31], year[5], comment[31];
 203         off_t fpos;
 204
 205         if (numbytes < 128 || strncmp("TAG", (char *)map + numbytes - 128, 3)) {
 206                 PARA_DEBUG_LOG("no id3 v1 tag\n");
 207                 return make_message("%s: (no id3 v1 tag)\n%s:\n",
 208                         status_item_list[SI_TAGINFO1],
 209                         status_item_list[SI_TAGINFO2]);
 210         }
 211         fpos = numbytes - 125;
 212         memcpy(title, map + fpos, 30);
 213         fpos += 30;
 214         title[30] = '\0';
 215         memcpy(artist, map + fpos, 30);
 216         fpos += 30;
 217         artist[30] = '\0';
 218         memcpy(album, map + fpos, 30);
 219         fpos += 30;
 220         album[30] = '\0';
 221         memcpy(year, map + fpos, 4);
 222         fpos += 4;
 223         year[4] = '\0';
 224         memcpy(comment, map + fpos, 30);
 225         comment[30] = '\0';
 226         unpad(title);
 227         unpad(artist);
 228         unpad(album);
 229         unpad(year);
 230         unpad(comment);
 231         return make_taginfo(title, artist, album, year, comment);
 232 }
 233 #endif /* HAVE_LIBID3TAG */
 234
 235 static int header_frequency(struct mp3header *h)
 236 {
 237         if (h->version > 2 || h->freq > 3)
 238                 return -E_HEADER_FREQ;
 239         return frequencies[h->version][h->freq];
 240 }
 241
 242 static const char *header_mode(struct mp3header *h)
 243 {
 244         if (h->mode > 4)
 245                 h->mode = 4; /* invalid */
 246         return mode_text[h->mode];
 247 }
 248
 249 static int header_channels(struct mp3header *h)
 250 {
 251         if (h->mode > 3)
 252                 return 0;
 253         if (h->mode < 3)
 254                 return 2;
 255         return 1;
 256 }
 257
 258 static int header_bitrate(struct mp3header *h)
 259 {
 260         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 261                 return -E_HEADER_BITRATE;
 262         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 263 }
 264
 265 static int frame_length(struct mp3header *header)
 266 {
 267         int hb, hf = header_frequency(header);
 268
 269         if (hf < 0)
 270                 return hf;
 271         hb = header_bitrate(header);
 272         if (hb < 0)
 273                 return hb;
 274         if (header->sync != 0xFFE || header->layer > 3)
 275                 return -E_FRAME;
 276         return frame_size_index[3 - header->layer] *
 277                 ((header->version & 1) + 1) * hb / hf
 278                 + header->padding;
 279 }
 280
 281 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 282 {
 283         if ((*(unsigned int*)h1) == (*(unsigned int*)h2))
 284                 return 1;
 285         if ((h1->version == h2->version) &&
 286                         (h1->layer == h2->layer) &&
 287                         (h1->crc == h2->crc) &&
 288                         (h1->freq == h2->freq) &&
 289                         (h1->mode == h2->mode) &&
 290                         (h1->copyright == h2->copyright) &&
 291                         (h1->original == h2->original) &&
 292                         (h1->emphasis == h2->emphasis))
 293                 return 1;
 294         return 0;
 295 }
 296
 297 /*
 298  * get next MP3 frame header.
 299  *
 300  * On success, the header frame length is returned and the given header
 301  * structure that is filled in.  A return value of zero means that we did not
 302  * retrieve a valid frame header, and a negative return value indicates an
 303  * error.
 304  */
 305 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 306         struct mp3header *header)
 307 {
 308         int fl, ret;
 309
 310         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 311                 *fpos = numbytes - 1;
 312                 header->sync = 0;
 313                 return 0;
 314         }
 315         header->layer = (map[*fpos + 1] >> 1) & 3;
 316         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 317         if (map[*fpos + 1] & 0x10)
 318                 header->version = (map[*fpos + 1] >> 3) & 1;
 319         else
 320                 header->version = 2;
 321         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 322                 ret = 0;
 323                 header->sync = 0;
 324                 goto out;
 325         }
 326         header->crc = map[*fpos + 1] & 1;
 327         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 328         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 329         header->padding = (map[*fpos + 2] >>1) & 0x1;
 330         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 331         fl = frame_length(header);
 332         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 333 out:
 334         *fpos += FRAME_HEADER_SIZE;
 335         return ret;
 336 }
 337
 338 /*
 339  * find the next mp3 header
 340  *
 341  * Return the length of the next frame header or zero if the end of the file is
 342  * reached.
 343  */
 344 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
 345         struct mp3header *result)
 346 {
 347         int k, l = 0, first_len;
 348         struct mp3header h, h2;
 349         long valid_start = 0;
 350
 351         for (; *fpos < numbytes; (*fpos)++) {
 352                 if (map[*fpos] != 0xff)
 353                         continue;
 354                 valid_start = *fpos;
 355                 first_len = get_header(map, numbytes, fpos, &h);
 356                 if (first_len <= 0)
 357                         continue;
 358                 *fpos += first_len - FRAME_HEADER_SIZE;
 359                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 360                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 361                                 break;
 362                         if (!compare_headers(&h, &h2))
 363                                 break;
 364                         *fpos += l - FRAME_HEADER_SIZE;
 365                 }
 366                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 367                         *fpos = valid_start;
 368                         *result = h2;
 369                         return first_len;
 370                 }
 371         }
 372         return 0;
 373 }
 374
 375 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
 376         struct mp3header *header)
 377 {
 378         int frame_len;
 379
 380         frame_len = get_header(map, numbytes, fpos, header);
 381         if (frame_len < 0)
 382                 return frame_len;
 383         if (!frame_len) {
 384                 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
 385                 if (frame_len <= 0)
 386                         return frame_len;
 387         } else
 388                 *fpos -= FRAME_HEADER_SIZE;
 389         if (frame_len <= 1)
 390                 return -E_FRAME_LENGTH;
 391         return frame_len;
 392 }
 393
 394 static int mp3_read_info(unsigned char *map, size_t numbytes, int fd,
 395                 struct afh_info *afhi)
 396 {
 397         uint64_t freq_sum = 0, br_sum = 0;
 398         int fl = 0, ret, len = 0, old_br = -1, vbr = 0;
 399         struct timeval total_time = {0, 0};
 400         unsigned chunk_table_size = 1000; /* gets increased on demand */
 401         off_t fpos = 0;
 402         struct mp3header header;
 403         char *taginfo;
 404
 405         afhi->chunks_total = 0;
 406         afhi->chunk_table = para_malloc(chunk_table_size * sizeof(uint32_t));
 407         taginfo = mp3_get_id3(map, numbytes, fd);
 408         while (1) {
 409                 int freq, br;
 410                 struct timeval tmp, cct; /* current chunk time */
 411                 fpos += len;
 412                 len = find_valid_start(map, numbytes, &fpos, &header);
 413                 if (len <= 0) {
 414                         size_t end;
 415                         ret = -E_MP3_INFO;
 416                         if (!afhi->chunks_total)
 417                                 goto err_out;
 418                         end = afhi->chunk_table[afhi->chunks_total - 1] + fl;
 419                         afhi->chunk_table[afhi->chunks_total]
 420                                 = PARA_MIN(end, numbytes);
 421                         break;
 422                 }
 423                 ret = header_frequency(&header);
 424                 if (ret < 0)
 425                         continue;
 426                 freq = ret;
 427                 ret = header_bitrate(&header);
 428                 if (ret < 0)
 429                         continue;
 430                 br = ret;
 431                 ret = frame_length(&header);
 432                 if (ret < 0)
 433                         continue;
 434                 fl = ret;
 435                 tmp.tv_sec = fl;
 436                 tmp.tv_usec = 0;
 437                 tv_divide(br * 125, &tmp, &cct);
 438                 tv_add(&cct, &total_time, &tmp);
 439                 total_time = tmp;
 440                 if (afhi->chunks_total >= chunk_table_size) {
 441                         chunk_table_size *= 2;
 442                         afhi->chunk_table = para_realloc(afhi->chunk_table,
 443                                 chunk_table_size * sizeof(uint32_t));
 444                 }
 445                 afhi->chunk_table[afhi->chunks_total] = fpos;
 446                 afhi->chunks_total++;
 447                 freq_sum += freq;
 448                 br_sum += br;
 449                 if (afhi->chunks_total != 1 && old_br != br)
 450                         vbr = 1;
 451                 old_br = br;
 452         }
 453         ret = -E_MP3_INFO;
 454         if (!freq_sum || !br_sum)
 455                 goto err_out;
 456         afhi->bitrate = br_sum / afhi->chunks_total;
 457         afhi->frequency = freq_sum / afhi->chunks_total;
 458         afhi->channels = header_channels(&header);
 459         afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 460         tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
 461         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
 462                 tv2ms(&afhi->chunk_tv));
 463         tv_scale(3, &afhi->chunk_tv, &afhi->eof_tv);
 464         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afhi->eof_tv));
 465         afhi->info_string = make_message("%s: %cbr, %s\n%s",
 466                 status_item_list[SI_AUDIO_FILE_INFO], vbr? 'v' : 'c',
 467                 header_mode(&header), taginfo);
 468         free(taginfo);
 469         return 1;
 470 err_out:
 471         free(taginfo);
 472         PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 473         free(afhi->chunk_table);
 474         return ret;
 475 }
 476
 477 /*
 478  * Read mp3 information from audio file
 479  */
 480 static int mp3_get_file_info(char *map, size_t numbytes, int fd,
 481                 struct afh_info *afhi)
 482 {
 483         int ret;
 484
 485         ret = mp3_read_info((unsigned char *)map, numbytes, fd, afhi);
 486         if (ret < 0)
 487                 return ret;
 488         if (afhi->seconds_total < 2 || !afhi->chunks_total)
 489                 return -E_MP3_INFO;
 490         return 1;
 491 }
 492
 493 static const char* mp3_suffixes[] = {"mp3", NULL};
 494
 495 /**
 496  * the init function of the mp3 audio format handler
 497  *
 498  * \param afh pointer to the struct to initialize
 499  */
 500 void mp3_init(struct audio_format_handler *afh)
 501 {
 502         afh->get_file_info = mp3_get_file_info;
 503         afh->suffixes = mp3_suffixes;
 504 }