mp3_afh.c

   1 /*
   2  * Copyright (C) 2003-2007 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 struct id3tag {
  51         char title[31];
  52         char artist[31];
  53         char album[31];
  54         char year[5];
  55         char comment[31];
  56 };
  57
  58 struct mp3info {
  59         struct mp3header header;
  60         int id3_isvalid;
  61         struct id3tag id3;
  62         int vbr;
  63 };
  64
  65 /** \endcond */
  66 static const int frequencies[3][4] = {
  67         {22050,24000,16000,50000}, /* MPEG 2.0 */
  68         {44100,48000,32000,50000}, /* MPEG 1.0 */
  69         {11025,12000,8000,50000} /* MPEG 2.5 */
  70 };
  71
  72 static const int mp3info_bitrate[2][3][14] = {
  73 { /* MPEG 2.0 */
  74         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  75         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  76         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  77 },
  78
  79 { /* MPEG 1.0 */
  80         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  81         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  82         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  83 }
  84 };
  85
  86 static const int frame_size_index[] = {24000, 72000, 72000};
  87 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  88
  89 static struct mp3info mp3;
  90
  91 static int header_frequency(struct mp3header *h)
  92 {
  93         if (h->version > 2 || h->freq > 3)
  94                 return -E_HEADER_FREQ;
  95         return frequencies[h->version][h->freq];
  96 }
  97
  98 static const char *header_mode(struct mp3header *h)
  99 {
 100         if (h->mode > 4)
 101                 h->mode = 4; /* invalid */
 102         return mode_text[h->mode];
 103 }
 104
 105 static int header_channels(struct mp3header *h)
 106 {
 107         if (h->mode > 3)
 108                 return 0;
 109         if (h->mode < 3)
 110                 return 2;
 111         return 1;
 112 }
 113
 114 static int header_bitrate(struct mp3header *h)
 115 {
 116         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 117                 return -E_HEADER_BITRATE;
 118         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 119 }
 120
 121 static int frame_length(struct mp3header *header)
 122 {
 123         int hb, hf = header_frequency(header);
 124
 125         if (hf < 0)
 126                 return hf;
 127         hb = header_bitrate(header);
 128         if (hb < 0)
 129                 return hb;
 130         if (header->sync != 0xFFE || header->layer > 3)
 131                 return -E_FRAME;
 132         return frame_size_index[3 - header->layer] *
 133                 ((header->version & 1) + 1) * hb / hf
 134                 + header->padding;
 135 }
 136
 137 static void write_info_str(struct afh_info *afhi)
 138 {
 139         int v = mp3.id3_isvalid;
 140
 141         snprintf(afhi->info_string, MMD_INFO_SIZE,
 142                 "%s: %cbr, %s\n" /* audio file info*/
 143                 "%s: %s, by %s\n" /* taginfo1 */
 144                 "%s: A: %s, Y: %s, C: %s\n", /* taginfo 2*/
 145                 status_item_list[SI_AUDIO_FILE_INFO], mp3.vbr? 'v' : 'c',
 146                         header_mode(&mp3.header),
 147                 status_item_list[SI_TAGINFO1], v && *mp3.id3.title?
 148                         mp3.id3.title : "(title tag not set)",
 149                         v && *mp3.id3.artist?
 150                         mp3.id3.artist : "(artist tag not set)",
 151                 status_item_list[SI_TAGINFO2],
 152                         v && *mp3.id3.album?
 153                                 mp3.id3.album : "(album tag not set)",
 154                         v && *mp3.id3.year? mp3.id3.year : "????",
 155                         v && *mp3.id3.comment?
 156                                 mp3.id3.comment : "(comment tag not set)"
 157         );
 158 }
 159
 160 /*
 161  * Remove trailing whitespace from the end of a string
 162  */
 163 static char *unpad(char *string)
 164 {
 165         char *pos = string + strlen(string) - 1;
 166         while (para_isspace(pos[0]))
 167                 (pos--)[0] = 0;
 168         return string;
 169 }
 170
 171 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 172 {
 173         if ((*(uint*)h1) == (*(uint*)h2))
 174                 return 1;
 175         if ((h1->version == h2->version) &&
 176                         (h1->layer == h2->layer) &&
 177                         (h1->crc == h2->crc) &&
 178                         (h1->freq == h2->freq) &&
 179                         (h1->mode == h2->mode) &&
 180                         (h1->copyright == h2->copyright) &&
 181                         (h1->original == h2->original) &&
 182                         (h1->emphasis == h2->emphasis))
 183                 return 1;
 184         return 0;
 185 }
 186
 187 /*
 188  * get next MP3 frame header.
 189  *
 190  * On success, the header frame length is returned and the given header
 191  * structure that is filled in.  A return value of zero means that we did not
 192  * retrieve a valid frame header, and a negative return value indicates an
 193  * error.
 194  */
 195 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 196         struct mp3header *header)
 197 {
 198         int fl, ret;
 199
 200         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 201                 *fpos = numbytes - 1;
 202                 header->sync = 0;
 203                 return 0;
 204         }
 205         header->layer = (map[*fpos + 1] >> 1) & 3;
 206         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 207         if (map[*fpos + 1] & 0x10)
 208                 header->version = (map[*fpos + 1] >> 3) & 1;
 209         else
 210                 header->version = 2;
 211         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 212                 ret = 0;
 213                 header->sync = 0;
 214                 goto out;
 215         }
 216         header->crc = map[*fpos + 1] & 1;
 217         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 218         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 219         header->padding = (map[*fpos + 2] >>1) & 0x1;
 220         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 221         fl = frame_length(header);
 222         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 223 out:
 224         *fpos += FRAME_HEADER_SIZE;
 225         return ret;
 226 }
 227
 228 /*
 229  * find the next mp3 header
 230  *
 231  * Return the length of the next frame header or zero if the end of the file is
 232  * reached.
 233  */
 234 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos)
 235 {
 236         int k, l = 0, first_len;
 237         struct mp3header h, h2;
 238         long valid_start = 0;
 239
 240         for (; *fpos < numbytes; (*fpos)++) {
 241                 if (map[*fpos] != 0xff)
 242                         continue;
 243                 valid_start = *fpos;
 244                 first_len = get_header(map, numbytes, fpos, &h);
 245                 if (first_len <= 0)
 246                         continue;
 247                 *fpos += first_len - FRAME_HEADER_SIZE;
 248                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 249                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 250                                 break;
 251                         if (!compare_headers(&h, &h2))
 252                                 break;
 253                         *fpos += l - FRAME_HEADER_SIZE;
 254                 }
 255                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 256                         *fpos = valid_start;
 257                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 258                         return first_len;
 259                 }
 260         }
 261         return 0;
 262 }
 263
 264 static void mp3_get_id3(unsigned char *map, size_t numbytes, off_t *fpos)
 265 {
 266         mp3.id3_isvalid = 0;
 267         mp3.id3.title[0] = '\0';
 268         mp3.id3.artist[0] = '\0';
 269         mp3.id3.album[0] = '\0';
 270         mp3.id3.comment[0] = '\0';
 271         mp3.id3.year[0] = '\0';
 272         if (numbytes < 128)
 273                 return;
 274         *fpos = numbytes - 128;
 275         if (strncmp("TAG", (char *) map + *fpos, 3)) {
 276                 PARA_DEBUG_LOG("%s", "no id3 tag\n");
 277                 return;
 278         }
 279         *fpos = numbytes - 125;
 280         memcpy(mp3.id3.title, map + *fpos, 30);
 281         *fpos += 30;
 282         mp3.id3.title[30] = '\0';
 283         memcpy(mp3.id3.artist, map + *fpos, 30);
 284         *fpos += 30;
 285         mp3.id3.artist[30] = '\0';
 286         memcpy(mp3.id3.album, map + *fpos, 30);
 287         *fpos += 30;
 288         mp3.id3.album[30] = '\0';
 289         memcpy(mp3.id3.year, map + *fpos, 4);
 290         *fpos += 4;
 291         mp3.id3.year[4] = '\0';
 292         memcpy(mp3.id3.comment, map + *fpos, 30);
 293         mp3.id3.comment[30] = '\0';
 294         mp3.id3_isvalid = 1;
 295         unpad(mp3.id3.title);
 296         unpad(mp3.id3.artist);
 297         unpad(mp3.id3.album);
 298         unpad(mp3.id3.year);
 299         unpad(mp3.id3.comment);
 300 }
 301
 302 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos)
 303 {
 304         int frame_len;
 305
 306         frame_len = get_header(map, numbytes, fpos, &mp3.header);
 307         if (frame_len < 0)
 308                 return frame_len;
 309         if (!frame_len) {
 310                 frame_len = mp3_seek_next_header(map, numbytes, fpos);
 311                 if (frame_len <= 0)
 312                         return frame_len;
 313         } else
 314                 *fpos -= FRAME_HEADER_SIZE;
 315         if (frame_len <= 1)
 316                 return -E_FRAME_LENGTH;
 317         return frame_len;
 318 }
 319
 320 static int mp3_read_info(unsigned char *map, size_t numbytes,
 321                 struct afh_info *afhi)
 322 {
 323         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 324         int ret, len = 0, old_br = -1;
 325         struct timeval total_time = {0, 0};
 326         unsigned chunk_table_size = 1000; /* gets increased on demand */
 327         off_t fpos = 0;
 328
 329         afhi->chunks_total = 0;
 330         afhi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 331         mp3_get_id3(map, numbytes, &fpos);
 332         fpos = 0;
 333         mp3.vbr = 0;
 334         while (1) {
 335                 unsigned long freq, br, fl;
 336                 struct timeval tmp, cct; /* current chunk time */
 337                 fpos += len;
 338                 len = find_valid_start(map, numbytes, &fpos);
 339                 if (len <= 0)
 340                         break;
 341                 ret = header_frequency(&mp3.header);
 342                 if (ret < 0)
 343                         continue;
 344                 freq = ret;
 345                 ret = header_bitrate(&mp3.header);
 346                 if (ret < 0)
 347                         continue;
 348                 br = ret;
 349                 ret = frame_length(&mp3.header);
 350                 if (ret < 0)
 351                         continue;
 352                 fl = ret;
 353                 tmp.tv_sec = fl;
 354                 tmp.tv_usec = 0;
 355                 tv_divide(br * 125, &tmp, &cct);
 356                 tv_add(&cct, &total_time, &tmp);
 357                 total_time = tmp;
 358                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 359                 if (afhi->chunks_total >= chunk_table_size) {
 360                         chunk_table_size *= 2;
 361                         afhi->chunk_table = para_realloc(afhi->chunk_table,
 362                                 chunk_table_size * sizeof(size_t));
 363                 }
 364                 afhi->chunk_table[afhi->chunks_total] = fpos;
 365 //              if (afhi->chunks_total < 10 || !(afhi->chunks_total % 1000))
 366 //                      PARA_INFO_LOG("chunk #%lu: %zd\n", afhi->chunks_total,
 367 //                              afhi->chunk_table[afhi->chunks_total]);
 368                 afhi->chunks_total++;
 369                 if (afhi->chunks_total == 1) {
 370                         freq_avg = freq;
 371                         br_avg = br;
 372                         old_br = br;
 373                         fl_avg = fl;
 374                         continue;
 375                 }
 376                 freq_avg += ((long)freq - freq_avg) / ((long)afhi->chunks_total + 1);
 377                 fl_avg += ((long)fl - fl_avg) / ((long)afhi->chunks_total + 1);
 378                 br_avg += ((long)br - br_avg) / ((long)afhi->chunks_total + 1);
 379                 if (old_br != br)
 380                         mp3.vbr = 1;
 381                 old_br = br;
 382         }
 383         ret = -E_MP3_INFO;
 384         if (!afhi->chunks_total || !freq_avg || !br_avg)
 385                 goto err_out;
 386         afhi->chunk_table[afhi->chunks_total] = numbytes - 1;
 387         afhi->bitrate = br_avg;
 388         afhi->frequency = freq_avg;
 389         afhi->channels = header_channels(&mp3.header);
 390         afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 391         tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
 392         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
 393                 tv2ms(&afhi->chunk_tv));
 394         tv_scale(3, &afhi->chunk_tv, &afhi->eof_tv);
 395         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afhi->eof_tv));
 396         return 1;
 397 err_out:
 398         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 399         free(afhi->chunk_table);
 400         return ret;
 401 }
 402
 403 /*
 404  * Read mp3 information from audio file
 405  */
 406 int mp3_get_file_info(char *map, size_t numbytes,
 407                 struct afh_info *afhi)
 408 {
 409         int ret;
 410
 411         ret = mp3_read_info((unsigned char *)map, numbytes, afhi);
 412         if (ret < 0)
 413                 return ret;
 414         write_info_str(afhi);
 415         if (afhi->seconds_total < 2 || !afhi->chunks_total)
 416                 return -E_MP3_INFO;
 417         return 1;
 418 }
 419
 420 static const char* mp3_suffixes[] = {"mp3", NULL};
 421
 422 /**
 423  * the init function of the mp3 audio format handler
 424  *
 425  * \param afh pointer to the struct to initialize
 426  */
 427 void mp3_init(struct audio_format_handler *afh)
 428 {
 429         afh->get_file_info = mp3_get_file_info;
 430         afh->suffixes = mp3_suffixes;
 431 }