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 "server.h"
  20 #include "error.h"
  21 #include "string.h"
  22
  23 /** \cond some defines and structs which are only used in this file */
  24
  25 /*
  26  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  27  * to see before we decide we are looking at a real MP3 file
  28  */
  29 #define MIN_CONSEC_GOOD_FRAMES 4
  30 #define FRAME_HEADER_SIZE 4
  31 #define MIN_FRAME_SIZE 21
  32
  33 struct mp3header {
  34         unsigned long sync;
  35         unsigned int version;
  36         unsigned int layer;
  37         unsigned int crc;
  38         unsigned int bitrate;
  39         unsigned int freq;
  40         unsigned int padding;
  41         unsigned int mode;
  42         unsigned int copyright;
  43         unsigned int original;
  44         unsigned int emphasis;
  45 };
  46
  47 struct id3tag {
  48         char title[31];
  49         char artist[31];
  50         char album[31];
  51         char year[5];
  52         char comment[31];
  53 };
  54
  55 struct mp3info {
  56         struct mp3header header;
  57         int id3_isvalid;
  58         struct id3tag id3;
  59         int vbr;
  60 };
  61
  62 /** \endcond */
  63 static const int frequencies[3][4] = {
  64         {22050,24000,16000,50000}, /* MPEG 2.0 */
  65         {44100,48000,32000,50000}, /* MPEG 1.0 */
  66         {11025,12000,8000,50000} /* MPEG 2.5 */
  67 };
  68
  69 static const int mp3info_bitrate[2][3][14] = {
  70 { /* MPEG 2.0 */
  71         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  72         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  73         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  74 },
  75
  76 { /* MPEG 1.0 */
  77         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  78         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  79         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  80 }
  81 };
  82
  83 static const int frame_size_index[] = {24000, 72000, 72000};
  84 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  85
  86 static struct mp3info mp3;
  87
  88 static int header_frequency(struct mp3header *h)
  89 {
  90         if (h->version > 2 || h->freq > 3)
  91                 return -E_HEADER_FREQ;
  92         return frequencies[h->version][h->freq];
  93 }
  94
  95 static const char *header_mode(struct mp3header *h)
  96 {
  97         if (h->mode > 4)
  98                 h->mode = 4; /* invalid */
  99         return mode_text[h->mode];
 100 }
 101
 102 static int header_channels(struct mp3header *h)
 103 {
 104         if (h->mode > 3)
 105                 return 0;
 106         if (h->mode < 3)
 107                 return 2;
 108         return 1;
 109 }
 110
 111 static int header_bitrate(struct mp3header *h)
 112 {
 113         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 114                 return -E_HEADER_BITRATE;
 115         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 116 }
 117
 118 static int frame_length(struct mp3header *header)
 119 {
 120         int hb, hf = header_frequency(header);
 121
 122         if (hf < 0)
 123                 return hf;
 124         hb = header_bitrate(header);
 125         if (hb < 0)
 126                 return hb;
 127         if (header->sync != 0xFFE || header->layer > 3)
 128                 return -E_FRAME;
 129         return frame_size_index[3 - header->layer] *
 130                 ((header->version & 1) + 1) * hb / hf
 131                 + header->padding;
 132 }
 133
 134 static void write_info_str(struct audio_format_info *afi)
 135 {
 136         int v = mp3.id3_isvalid;
 137
 138         snprintf(afi->info_string, MMD_INFO_SIZE,
 139                 "audio_file_info1:%lu x %lums, %u kbit/s (%cbr) %i KHz %s\n"
 140                 "audio_file_info2:%s, by %s\n"
 141                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 142                 afi->chunks_total,
 143                 tv2ms(&afi->chunk_tv),
 144                 afi->bitrate,
 145                 mp3.vbr? 'v' : 'c',
 146                 afi->frequency / 1000,
 147                 header_mode(&mp3.header),
 148                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 149                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 150                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 151                 v && *mp3.id3.year? mp3.id3.year : "????",
 152                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 153         );
 154 }
 155
 156 /*
 157  * Remove trailing whitespace from the end of a string
 158  */
 159 static char *unpad(char *string)
 160 {
 161         char *pos = string + strlen(string) - 1;
 162         while (isspace(pos[0]))
 163                 (pos--)[0] = 0;
 164         return string;
 165 }
 166
 167 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 168 {
 169         if ((*(uint*)h1) == (*(uint*)h2))
 170                 return 1;
 171         if ((h1->version == h2->version) &&
 172                         (h1->layer == h2->layer) &&
 173                         (h1->crc == h2->crc) &&
 174                         (h1->freq == h2->freq) &&
 175                         (h1->mode == h2->mode) &&
 176                         (h1->copyright == h2->copyright) &&
 177                         (h1->original == h2->original) &&
 178                         (h1->emphasis == h2->emphasis))
 179                 return 1;
 180         return 0;
 181 }
 182
 183 /*
 184  * get next MP3 frame header.
 185  *
 186  * On success, the header frame length is returned and the given header
 187  * structure that is filled in.  A return value of zero means that we did not
 188  * retrieve a valid frame header, and a negative return value indicates an
 189  * error.
 190  */
 191 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 192         struct mp3header *header)
 193 {
 194         int fl, ret;
 195
 196         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 197                 *fpos = numbytes - 1;
 198                 header->sync = 0;
 199                 return 0;
 200         }
 201         header->layer = (map[*fpos + 1] >> 1) & 3;
 202         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 203         if (map[*fpos + 1] & 0x10)
 204                 header->version = (map[*fpos + 1] >> 3) & 1;
 205         else
 206                 header->version = 2;
 207         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 208                 ret = 0;
 209                 header->sync = 0;
 210                 goto out;
 211         }
 212         header->crc = map[*fpos + 1] & 1;
 213         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 214         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 215         header->padding = (map[*fpos + 2] >>1) & 0x1;
 216         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 217         fl = frame_length(header);
 218         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 219 out:
 220         *fpos += FRAME_HEADER_SIZE;
 221         return ret;
 222 }
 223
 224 /*
 225  * find the next mp3 header
 226  *
 227  * Return the length of the next frame header or zero if the end of the file is
 228  * reached.
 229  */
 230 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos)
 231 {
 232         int k, l = 0, first_len;
 233         struct mp3header h, h2;
 234         long valid_start = 0;
 235
 236         for (; *fpos < numbytes; (*fpos)++) {
 237                 if (map[*fpos] != 0xff)
 238                         continue;
 239                 valid_start = *fpos;
 240                 first_len = get_header(map, numbytes, fpos, &h);
 241                 if (first_len <= 0)
 242                         continue;
 243                 *fpos += first_len - FRAME_HEADER_SIZE;
 244                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 245                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 246                                 break;
 247                         if (!compare_headers(&h, &h2))
 248                                 break;
 249                         *fpos += l - FRAME_HEADER_SIZE;
 250                 }
 251                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 252                         *fpos = valid_start;
 253                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 254                         return first_len;
 255                 }
 256         }
 257         return 0;
 258 }
 259
 260 static void mp3_get_id3(unsigned char *map, size_t numbytes, off_t *fpos)
 261 {
 262         mp3.id3_isvalid = 0;
 263         mp3.id3.title[0] = '\0';
 264         mp3.id3.artist[0] = '\0';
 265         mp3.id3.album[0] = '\0';
 266         mp3.id3.comment[0] = '\0';
 267         mp3.id3.year[0] = '\0';
 268         if (numbytes < 128)
 269                 return;
 270         *fpos = numbytes - 128;
 271         if (strncmp("TAG", (char *) map + *fpos, 3)) {
 272                 PARA_INFO_LOG("%s", "no id3 tag\n");
 273                 return;
 274         }
 275         *fpos = numbytes - 125;
 276         memcpy(mp3.id3.title, map + *fpos, 30);
 277         *fpos += 30;
 278         mp3.id3.title[30] = '\0';
 279         memcpy(mp3.id3.artist, map + *fpos, 30);
 280         *fpos += 30;
 281         mp3.id3.artist[30] = '\0';
 282         memcpy(mp3.id3.album, map + *fpos, 30);
 283         *fpos += 30;
 284         mp3.id3.album[30] = '\0';
 285         memcpy(mp3.id3.year, map + *fpos, 4);
 286         *fpos += 4;
 287         mp3.id3.year[4] = '\0';
 288         memcpy(mp3.id3.comment, map + *fpos, 30);
 289         mp3.id3.comment[30] = '\0';
 290         mp3.id3_isvalid = 1;
 291         unpad(mp3.id3.title);
 292         unpad(mp3.id3.artist);
 293         unpad(mp3.id3.album);
 294         unpad(mp3.id3.year);
 295         unpad(mp3.id3.comment);
 296 }
 297
 298 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos)
 299 {
 300         int frame_len;
 301
 302         frame_len = get_header(map, numbytes, fpos, &mp3.header);
 303         if (frame_len < 0)
 304                 return frame_len;
 305         if (!frame_len) {
 306                 frame_len = mp3_seek_next_header(map, numbytes, fpos);
 307                 if (frame_len <= 0)
 308                         return frame_len;
 309         } else
 310                 *fpos -= FRAME_HEADER_SIZE;
 311         if (frame_len <= 1)
 312                 return -E_FRAME_LENGTH;
 313         return frame_len;
 314 }
 315
 316 static int mp3_read_info(unsigned char *map, size_t numbytes,
 317                 struct audio_format_info *afi)
 318 {
 319         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 320         int ret, len = 0, old_br = -1;
 321         struct timeval total_time = {0, 0};
 322         unsigned chunk_table_size = 1000; /* gets increased on demand */
 323         off_t fpos = 0;
 324
 325         afi->chunks_total = 0;
 326         afi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 327         mp3_get_id3(map, numbytes, &fpos);
 328         fpos = 0;
 329         mp3.vbr = 0;
 330         while (1) {
 331                 unsigned long freq, br, fl;
 332                 struct timeval tmp, cct; /* current chunk time */
 333                 fpos += len;
 334                 len = find_valid_start(map, numbytes, &fpos);
 335                 if (len <= 0)
 336                         break;
 337                 ret = header_frequency(&mp3.header);
 338                 if (ret < 0)
 339                         continue;
 340                 freq = ret;
 341                 ret = header_bitrate(&mp3.header);
 342                 if (ret < 0)
 343                         continue;
 344                 br = ret;
 345                 ret = frame_length(&mp3.header);
 346                 if (ret < 0)
 347                         continue;
 348                 fl = ret;
 349                 tmp.tv_sec = fl;
 350                 tmp.tv_usec = 0;
 351                 tv_divide(br * 125, &tmp, &cct);
 352                 tv_add(&cct, &total_time, &tmp);
 353                 total_time = tmp;
 354                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 355                 if (afi->chunks_total >= chunk_table_size) {
 356                         chunk_table_size *= 2;
 357                         afi->chunk_table = para_realloc(afi->chunk_table,
 358                                 chunk_table_size * sizeof(size_t));
 359                 }
 360                 afi->chunk_table[afi->chunks_total] = fpos;
 361 //              if (afi->chunks_total < 10 || !(afi->chunks_total % 1000))
 362 //                      PARA_INFO_LOG("chunk #%lu: %zd\n", afi->chunks_total,
 363 //                              afi->chunk_table[afi->chunks_total]);
 364                 afi->chunks_total++;
 365                 if (afi->chunks_total == 1) {
 366                         freq_avg = freq;
 367                         br_avg = br;
 368                         old_br = br;
 369                         fl_avg = fl;
 370                         continue;
 371                 }
 372                 freq_avg += ((long)freq - freq_avg) / ((long)afi->chunks_total + 1);
 373                 fl_avg += ((long)fl - fl_avg) / ((long)afi->chunks_total + 1);
 374                 br_avg += ((long)br - br_avg) / ((long)afi->chunks_total + 1);
 375                 if (old_br != br)
 376                         mp3.vbr = 1;
 377                 old_br = br;
 378         }
 379         ret = -E_MP3_INFO;
 380         if (!afi->chunks_total || !freq_avg || !br_avg)
 381                 goto err_out;
 382         afi->chunk_table[afi->chunks_total] = numbytes - 1;
 383         afi->bitrate = br_avg;
 384         afi->frequency = freq_avg;
 385         afi->channels = header_channels(&mp3.header);
 386         afi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 387         tv_divide(afi->chunks_total, &total_time, &afi->chunk_tv);
 388         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afi->chunks_total,
 389                 tv2ms(&afi->chunk_tv));
 390         tv_scale(3, &afi->chunk_tv, &afi->eof_tv);
 391         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afi->eof_tv));
 392         return 1;
 393 err_out:
 394         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 395         free(afi->chunk_table);
 396         return ret;
 397 }
 398
 399 /*
 400  * Read mp3 information from audio file
 401  */
 402 static int mp3_get_file_info(char *map, size_t numbytes,
 403                 struct audio_format_info *afi)
 404 {
 405         int ret;
 406
 407         ret = mp3_read_info((unsigned char *)map, numbytes, afi);
 408         if (ret < 0)
 409                 return ret;
 410         write_info_str(afi);
 411         if (afi->seconds_total < 2 || !afi->chunks_total)
 412                 return -E_MP3_INFO;
 413         return 1;
 414 }
 415
 416 static const char* mp3_suffixes[] = {"mp3", NULL};
 417
 418 /**
 419  * the init function of the mp3 audio format handler
 420  *
 421  * \param afh pointer to the struct to initialize
 422  */
 423 void mp3_init(struct audio_format_handler *afh)
 424 {
 425         afh->get_file_info = mp3_get_file_info;
 426         afh->suffixes = mp3_suffixes;
 427 }