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