mp3_afh.c

   1 /*
   2  * Copyright (C) 2003-2012 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
  21 #include "para.h"
  22 #include "error.h"
  23 #include "afh.h"
  24 #include "string.h"
  25
  26 /*
  27  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  28  * to see before we decide we are looking at a real MP3 file
  29  */
  30 #define MIN_CONSEC_GOOD_FRAMES 4
  31 #define FRAME_HEADER_SIZE 4
  32 #define MIN_FRAME_SIZE 21
  33
  34 struct mp3header {
  35         unsigned long sync;
  36         unsigned int version;
  37         unsigned int layer;
  38         unsigned int crc;
  39         unsigned int bitrate;
  40         unsigned int freq;
  41         unsigned int padding;
  42         unsigned int mode;
  43         unsigned int copyright;
  44         unsigned int original;
  45         unsigned int emphasis;
  46 };
  47
  48 static const int frequencies[3][4] = {
  49         {22050,24000,16000,50000}, /* MPEG 2.0 */
  50         {44100,48000,32000,50000}, /* MPEG 1.0 */
  51         {11025,12000,8000,50000} /* MPEG 2.5 */
  52 };
  53
  54 static const int mp3info_bitrate[2][3][14] = {
  55 { /* MPEG 2.0 */
  56         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  57         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  58         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  59 },
  60
  61 { /* MPEG 1.0 */
  62         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  63         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  64         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  65 }
  66 };
  67
  68 static const int frame_size_index[] = {24000, 72000, 72000};
  69 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  70
  71 #ifdef HAVE_LIBID3TAG
  72
  73 #include <id3tag.h>
  74
  75 static char *get_latin1(id3_ucs4_t const *string)
  76 {
  77         if (!string)
  78                 return NULL;
  79         return (char *)id3_ucs4_latin1duplicate(string);
  80 }
  81
  82 static char *get_stringlist(union id3_field *field)
  83 {
  84         unsigned int k, nstrings = id3_field_getnstrings(field);
  85         char *result = NULL;
  86
  87         for (k = 0; k < nstrings; k++) {
  88                 char *tmp = (char *)get_latin1(id3_field_getstrings(field, k));
  89                 if (result) {
  90                         char *tmp2 = result;
  91                         result = make_message("%s %s", tmp2, tmp);
  92                         free(tmp);
  93                         free(tmp2);
  94                 } else
  95                         result = tmp;
  96         }
  97         return result;
  98 }
  99
 100 static char *get_string(union id3_field *field)
 101 {
 102         id3_ucs4_t const *string = id3_field_getfullstring(field);
 103
 104         return get_latin1(string);
 105 }
 106
 107 #define FOR_EACH_FIELD(f, j, fr) for (j = 0; j < (fr)->nfields && \
 108         (f = id3_frame_field((fr), j)); j++)
 109
 110 static char *get_strings(struct id3_frame *fr)
 111 {
 112         int j;
 113         union id3_field *field;
 114
 115         FOR_EACH_FIELD(field, j, fr) {
 116                 enum id3_field_type type = id3_field_type(field);
 117
 118                 if (type == ID3_FIELD_TYPE_STRINGLIST)
 119                         return get_stringlist(field);
 120                 if (type == ID3_FIELD_TYPE_STRINGFULL)
 121                         return get_string(field);
 122         }
 123         return NULL;
 124 }
 125
 126 static void mp3_get_id3(__a_unused unsigned char *map,
 127                 __a_unused size_t numbytes, int fd, struct taginfo *tags)
 128 {
 129         int i;
 130         struct id3_tag *id3_t;
 131         struct id3_file *id3_f = id3_file_fdopen(fd, ID3_FILE_MODE_READONLY);
 132
 133         if (!id3_f)
 134                 return;
 135         id3_t = id3_file_tag(id3_f);
 136         if (!id3_t) {
 137                 id3_file_close(id3_f);
 138                 return;
 139         }
 140         for (i = 0; i < id3_t->nframes; i++) {
 141                 struct id3_frame *fr = id3_t->frames[i];
 142                 if (!strcmp(fr->id, "TIT2")) {
 143                         if (!tags->title)
 144                                 tags->title = get_strings(fr);
 145                         continue;
 146                 }
 147                 if (!strcmp(fr->id, "TPE1")) {
 148                         if (!tags->artist)
 149                                 tags->artist = get_strings(fr);
 150                         continue;
 151                 }
 152                 if (!strcmp(fr->id, "TALB")) {
 153                         if (!tags->album)
 154                                 tags->album = get_strings(fr);
 155                         continue;
 156                 }
 157                 if (!strcmp(fr->id, "TDRC")) {
 158                         if (!tags->year)
 159                                 tags->year = get_strings(fr);
 160                         continue;
 161                 }
 162                 if (!strcmp(fr->id, "COMM")) {
 163                         if (!tags->comment)
 164                                 tags->comment = get_strings(fr);
 165                         continue;
 166                 }
 167         }
 168         id3_file_close(id3_f);
 169 }
 170
 171 #else /* HAVE_LIBID3TAG */
 172
 173 /*
 174  * Remove trailing whitespace from the end of a string
 175  */
 176 static char *unpad(char *string)
 177 {
 178         char *pos = string + strlen(string) - 1;
 179         while (para_isspace(pos[0]))
 180                 (pos--)[0] = 0;
 181         return string;
 182 }
 183
 184 static void mp3_get_id3(unsigned char *map, size_t numbytes, __a_unused int fd,
 185         struct taginfo *tags)
 186 {
 187         char title[31], artist[31], album[31], year[5], comment[31];
 188         off_t fpos;
 189
 190         if (numbytes < 128 || strncmp("TAG", (char *)map + numbytes - 128, 3)) {
 191                 PARA_DEBUG_LOG("no id3 v1 tag\n");
 192                 return;
 193         }
 194         fpos = numbytes - 125;
 195         memcpy(title, map + fpos, 30);
 196         fpos += 30;
 197         title[30] = '\0';
 198         memcpy(artist, map + fpos, 30);
 199         fpos += 30;
 200         artist[30] = '\0';
 201         memcpy(album, map + fpos, 30);
 202         fpos += 30;
 203         album[30] = '\0';
 204         memcpy(year, map + fpos, 4);
 205         fpos += 4;
 206         year[4] = '\0';
 207         memcpy(comment, map + fpos, 30);
 208         comment[30] = '\0';
 209         unpad(title);
 210         unpad(artist);
 211         unpad(album);
 212         unpad(year);
 213         unpad(comment);
 214         tags->artist = para_strdup(artist);
 215         tags->title = para_strdup(title);
 216         tags->year = para_strdup(year);
 217         tags->album = para_strdup(album);
 218         tags->comment = para_strdup(comment);
 219 }
 220 #endif /* HAVE_LIBID3TAG */
 221
 222 static int header_frequency(struct mp3header *h)
 223 {
 224         if (h->version > 2 || h->freq > 3)
 225                 return -E_HEADER_FREQ;
 226         return frequencies[h->version][h->freq];
 227 }
 228
 229 static const char *header_mode(struct mp3header *h)
 230 {
 231         if (h->mode > 4)
 232                 h->mode = 4; /* invalid */
 233         return mode_text[h->mode];
 234 }
 235
 236 static int header_channels(struct mp3header *h)
 237 {
 238         if (h->mode > 3)
 239                 return 0;
 240         if (h->mode < 3)
 241                 return 2;
 242         return 1;
 243 }
 244
 245 static int header_bitrate(struct mp3header *h)
 246 {
 247         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 248                 return -E_HEADER_BITRATE;
 249         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 250 }
 251
 252 static int frame_length(struct mp3header *header)
 253 {
 254         int hb, hf = header_frequency(header);
 255
 256         if (hf < 0)
 257                 return hf;
 258         hb = header_bitrate(header);
 259         if (hb < 0)
 260                 return hb;
 261         if (header->sync != 0xFFE || header->layer > 3)
 262                 return -E_FRAME;
 263         return frame_size_index[3 - header->layer] *
 264                 ((header->version & 1) + 1) * hb / hf
 265                 + header->padding;
 266 }
 267
 268 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 269 {
 270         if ((*(unsigned int*)h1) == (*(unsigned int*)h2))
 271                 return 1;
 272         if ((h1->version == h2->version) &&
 273                         (h1->layer == h2->layer) &&
 274                         (h1->crc == h2->crc) &&
 275                         (h1->freq == h2->freq) &&
 276                         (h1->mode == h2->mode) &&
 277                         (h1->copyright == h2->copyright) &&
 278                         (h1->original == h2->original) &&
 279                         (h1->emphasis == h2->emphasis))
 280                 return 1;
 281         return 0;
 282 }
 283
 284 /*
 285  * get next MP3 frame header.
 286  *
 287  * On success, the header frame length is returned and the given header
 288  * structure that is filled in.  A return value of zero means that we did not
 289  * retrieve a valid frame header, and a negative return value indicates an
 290  * error.
 291  */
 292 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 293         struct mp3header *header)
 294 {
 295         int fl, ret;
 296
 297         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 298                 *fpos = numbytes - 1;
 299                 header->sync = 0;
 300                 return 0;
 301         }
 302         header->layer = (map[*fpos + 1] >> 1) & 3;
 303         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 304         if (map[*fpos + 1] & 0x10)
 305                 header->version = (map[*fpos + 1] >> 3) & 1;
 306         else
 307                 header->version = 2;
 308         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 309                 ret = 0;
 310                 header->sync = 0;
 311                 goto out;
 312         }
 313         header->crc = map[*fpos + 1] & 1;
 314         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 315         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 316         header->padding = (map[*fpos + 2] >>1) & 0x1;
 317         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 318         fl = frame_length(header);
 319         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 320 out:
 321         *fpos += FRAME_HEADER_SIZE;
 322         return ret;
 323 }
 324
 325 /*
 326  * find the next mp3 header
 327  *
 328  * Return the length of the next frame header or zero if the end of the file is
 329  * reached.
 330  */
 331 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
 332         struct mp3header *result)
 333 {
 334         int k, l = 0, first_len;
 335         struct mp3header h, h2;
 336         long valid_start = 0;
 337
 338         for (; *fpos < numbytes; (*fpos)++) {
 339                 if (map[*fpos] != 0xff)
 340                         continue;
 341                 valid_start = *fpos;
 342                 first_len = get_header(map, numbytes, fpos, &h);
 343                 if (first_len <= 0)
 344                         continue;
 345                 *fpos += first_len - FRAME_HEADER_SIZE;
 346                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 347                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 348                                 break;
 349                         if (!compare_headers(&h, &h2))
 350                                 break;
 351                         *fpos += l - FRAME_HEADER_SIZE;
 352                 }
 353                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 354                         *fpos = valid_start;
 355                         *result = h2;
 356                         return first_len;
 357                 }
 358         }
 359         return 0;
 360 }
 361
 362 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
 363         struct mp3header *header)
 364 {
 365         int frame_len;
 366
 367         frame_len = get_header(map, numbytes, fpos, header);
 368         if (frame_len < 0)
 369                 return frame_len;
 370         if (!frame_len) {
 371                 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
 372                 if (frame_len <= 0)
 373                         return frame_len;
 374         } else
 375                 *fpos -= FRAME_HEADER_SIZE;
 376         if (frame_len <= 1)
 377                 return -E_FRAME_LENGTH;
 378         return frame_len;
 379 }
 380
 381 static int mp3_read_info(unsigned char *map, size_t numbytes, int fd,
 382                 struct afh_info *afhi)
 383 {
 384         uint64_t freq_sum = 0, br_sum = 0;
 385         int fl = 0, ret, len = 0, old_br = -1, vbr = 0;
 386         struct timeval total_time = {0, 0};
 387         unsigned chunk_table_size = 1000; /* gets increased on demand */
 388         off_t fpos = 0;
 389         struct mp3header header;
 390
 391         afhi->chunks_total = 0;
 392         afhi->chunk_table = para_malloc(chunk_table_size * sizeof(uint32_t));
 393         while (1) {
 394                 int freq, br;
 395                 struct timeval tmp, cct; /* current chunk time */
 396                 fpos += len;
 397                 len = find_valid_start(map, numbytes, &fpos, &header);
 398                 if (len <= 0) {
 399                         size_t end;
 400                         ret = -E_MP3_INFO;
 401                         if (!afhi->chunks_total)
 402                                 goto err_out;
 403                         end = afhi->chunk_table[afhi->chunks_total - 1] + fl;
 404                         afhi->chunk_table[afhi->chunks_total]
 405                                 = PARA_MIN(end, numbytes);
 406                         break;
 407                 }
 408                 ret = header_frequency(&header);
 409                 if (ret < 0)
 410                         continue;
 411                 freq = ret;
 412                 ret = header_bitrate(&header);
 413                 if (ret < 0)
 414                         continue;
 415                 br = ret;
 416                 ret = frame_length(&header);
 417                 if (ret < 0)
 418                         continue;
 419                 fl = ret;
 420                 tmp.tv_sec = fl - header.padding;
 421                 tmp.tv_usec = 0;
 422                 tv_divide(br * 125, &tmp, &cct);
 423                 tv_add(&cct, &total_time, &tmp);
 424                 total_time = tmp;
 425                 if (afhi->chunks_total >= chunk_table_size) {
 426                         chunk_table_size *= 2;
 427                         afhi->chunk_table = para_realloc(afhi->chunk_table,
 428                                 chunk_table_size * sizeof(uint32_t));
 429                 }
 430                 afhi->chunk_table[afhi->chunks_total] = fpos;
 431                 afhi->chunks_total++;
 432                 freq_sum += freq;
 433                 br_sum += br;
 434                 if (afhi->chunks_total != 1 && old_br != br)
 435                         vbr = 1;
 436                 old_br = br;
 437         }
 438         ret = -E_MP3_INFO;
 439         if (!freq_sum || !br_sum)
 440                 goto err_out;
 441         afhi->bitrate = br_sum / afhi->chunks_total;
 442         afhi->frequency = freq_sum / afhi->chunks_total;
 443         afhi->channels = header_channels(&header);
 444         afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 445         tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
 446         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
 447                 tv2ms(&afhi->chunk_tv));
 448         afhi->techinfo = make_message("%cbr, %s", vbr? 'v' : 'c',
 449                 header_mode(&header));
 450         mp3_get_id3(map, numbytes, fd, &afhi->tags);
 451         return 1;
 452 err_out:
 453         PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 454         free(afhi->chunk_table);
 455         return ret;
 456 }
 457
 458 /*
 459  * Read mp3 information from audio file
 460  */
 461 static int mp3_get_file_info(char *map, size_t numbytes, int fd,
 462                 struct afh_info *afhi)
 463 {
 464         int ret;
 465
 466         ret = mp3_read_info((unsigned char *)map, numbytes, fd, afhi);
 467         if (ret < 0)
 468                 return ret;
 469         if (afhi->seconds_total < 2 || !afhi->chunks_total)
 470                 return -E_MP3_INFO;
 471         return 1;
 472 }
 473
 474 static const char* mp3_suffixes[] = {"mp3", NULL};
 475
 476 /**
 477  * the init function of the mp3 audio format handler
 478  *
 479  * \param afh pointer to the struct to initialize
 480  */
 481 void mp3_init(struct audio_format_handler *afh)
 482 {
 483         afh->get_file_info = mp3_get_file_info;
 484         afh->suffixes = mp3_suffixes;
 485 }