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 "afh.h"
  21 #include "server.h"
  22 #include "error.h"
  23 #include "string.h"
  24
  25 /** \cond some defines and structs which are only used in this file */
  26
  27 /*
  28  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  29  * to see before we decide we are looking at a real MP3 file
  30  */
  31 #define MIN_CONSEC_GOOD_FRAMES 4
  32 #define FRAME_HEADER_SIZE 4
  33 #define MIN_FRAME_SIZE 21
  34
  35 struct mp3header {
  36         unsigned long sync;
  37         unsigned int version;
  38         unsigned int layer;
  39         unsigned int crc;
  40         unsigned int bitrate;
  41         unsigned int freq;
  42         unsigned int padding;
  43         unsigned int mode;
  44         unsigned int copyright;
  45         unsigned int original;
  46         unsigned int emphasis;
  47 };
  48
  49 struct id3tag {
  50         char title[31];
  51         char artist[31];
  52         char album[31];
  53         char year[5];
  54         char comment[31];
  55 };
  56
  57 struct mp3info {
  58         struct mp3header header;
  59         int id3_isvalid;
  60         struct id3tag id3;
  61         int vbr;
  62 };
  63
  64 /** \endcond */
  65 static const int frequencies[3][4] = {
  66         {22050,24000,16000,50000}, /* MPEG 2.0 */
  67         {44100,48000,32000,50000}, /* MPEG 1.0 */
  68         {11025,12000,8000,50000} /* MPEG 2.5 */
  69 };
  70
  71 static const int mp3info_bitrate[2][3][14] = {
  72 { /* MPEG 2.0 */
  73         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  74         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  75         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  76 },
  77
  78 { /* MPEG 1.0 */
  79         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  80         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  81         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  82 }
  83 };
  84
  85 static const int frame_size_index[] = {24000, 72000, 72000};
  86 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
  87
  88 static struct mp3info mp3;
  89
  90 static int header_frequency(struct mp3header *h)
  91 {
  92         if (h->version > 2 || h->freq > 3)
  93                 return -E_HEADER_FREQ;
  94         return frequencies[h->version][h->freq];
  95 }
  96
  97 static const char *header_mode(struct mp3header *h)
  98 {
  99         if (h->mode > 4)
 100                 h->mode = 4; /* invalid */
 101         return mode_text[h->mode];
 102 }
 103
 104 static int header_channels(struct mp3header *h)
 105 {
 106         if (h->mode > 3)
 107                 return 0;
 108         if (h->mode < 3)
 109                 return 2;
 110         return 1;
 111 }
 112
 113 static int header_bitrate(struct mp3header *h)
 114 {
 115         if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
 116                 return -E_HEADER_BITRATE;
 117         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 118 }
 119
 120 static int frame_length(struct mp3header *header)
 121 {
 122         int hb, hf = header_frequency(header);
 123
 124         if (hf < 0)
 125                 return hf;
 126         hb = header_bitrate(header);
 127         if (hb < 0)
 128                 return hb;
 129         if (header->sync != 0xFFE || header->layer > 3)
 130                 return -E_FRAME;
 131         return frame_size_index[3 - header->layer] *
 132                 ((header->version & 1) + 1) * hb / hf
 133                 + header->padding;
 134 }
 135
 136 static void write_info_str(struct audio_format_info *afi)
 137 {
 138         int v = mp3.id3_isvalid;
 139
 140         snprintf(afi->info_string, MMD_INFO_SIZE,
 141                 "audio_file_info1:%lu x %lums, %u kbit/s (%cbr) %i KHz %s\n"
 142                 "audio_file_info2:%s, by %s\n"
 143                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 144                 afi->chunks_total,
 145                 tv2ms(&afi->chunk_tv),
 146                 afi->bitrate,
 147                 mp3.vbr? 'v' : 'c',
 148                 afi->frequency / 1000,
 149                 header_mode(&mp3.header),
 150                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 151                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 152                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 153                 v && *mp3.id3.year? mp3.id3.year : "????",
 154                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 155         );
 156 }
 157
 158 /*
 159  * Remove trailing whitespace from the end of a string
 160  */
 161 static char *unpad(char *string)
 162 {
 163         char *pos = string + strlen(string) - 1;
 164         while (isspace(pos[0]))
 165                 (pos--)[0] = 0;
 166         return string;
 167 }
 168
 169 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 170 {
 171         if ((*(uint*)h1) == (*(uint*)h2))
 172                 return 1;
 173         if ((h1->version == h2->version) &&
 174                         (h1->layer == h2->layer) &&
 175                         (h1->crc == h2->crc) &&
 176                         (h1->freq == h2->freq) &&
 177                         (h1->mode == h2->mode) &&
 178                         (h1->copyright == h2->copyright) &&
 179                         (h1->original == h2->original) &&
 180                         (h1->emphasis == h2->emphasis))
 181                 return 1;
 182         return 0;
 183 }
 184
 185 /*
 186  * get next MP3 frame header.
 187  *
 188  * On success, the header frame length is returned and the given header
 189  * structure that is filled in.  A return value of zero means that we did not
 190  * retrieve a valid frame header, and a negative return value indicates an
 191  * error.
 192  */
 193 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
 194         struct mp3header *header)
 195 {
 196         int fl, ret;
 197
 198         if (*fpos + FRAME_HEADER_SIZE > numbytes) {
 199                 *fpos = numbytes - 1;
 200                 header->sync = 0;
 201                 return 0;
 202         }
 203         header->layer = (map[*fpos + 1] >> 1) & 3;
 204         header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
 205         if (map[*fpos + 1] & 0x10)
 206                 header->version = (map[*fpos + 1] >> 3) & 1;
 207         else
 208                 header->version = 2;
 209         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 210                 ret = 0;
 211                 header->sync = 0;
 212                 goto out;
 213         }
 214         header->crc = map[*fpos + 1] & 1;
 215         header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
 216         header->freq = (map[*fpos + 2] >> 2) & 0x3;
 217         header->padding = (map[*fpos + 2] >>1) & 0x1;
 218         header->mode = (map[*fpos + 3] >> 6) & 0x3;
 219         fl = frame_length(header);
 220         ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 221 out:
 222         *fpos += FRAME_HEADER_SIZE;
 223         return ret;
 224 }
 225
 226 /*
 227  * find the next mp3 header
 228  *
 229  * Return the length of the next frame header or zero if the end of the file is
 230  * reached.
 231  */
 232 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos)
 233 {
 234         int k, l = 0, first_len;
 235         struct mp3header h, h2;
 236         long valid_start = 0;
 237
 238         for (; *fpos < numbytes; (*fpos)++) {
 239                 if (map[*fpos] != 0xff)
 240                         continue;
 241                 valid_start = *fpos;
 242                 first_len = get_header(map, numbytes, fpos, &h);
 243                 if (first_len <= 0)
 244                         continue;
 245                 *fpos += first_len - FRAME_HEADER_SIZE;
 246                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 247                         if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
 248                                 break;
 249                         if (!compare_headers(&h, &h2))
 250                                 break;
 251                         *fpos += l - FRAME_HEADER_SIZE;
 252                 }
 253                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 254                         *fpos = valid_start;
 255                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 256                         return first_len;
 257                 }
 258         }
 259         return 0;
 260 }
 261
 262 static void mp3_get_id3(unsigned char *map, size_t numbytes, off_t *fpos)
 263 {
 264         mp3.id3_isvalid = 0;
 265         mp3.id3.title[0] = '\0';
 266         mp3.id3.artist[0] = '\0';
 267         mp3.id3.album[0] = '\0';
 268         mp3.id3.comment[0] = '\0';
 269         mp3.id3.year[0] = '\0';
 270         if (numbytes < 128)
 271                 return;
 272         *fpos = numbytes - 128;
 273         if (strncmp("TAG", (char *) map + *fpos, 3)) {
 274                 PARA_DEBUG_LOG("%s", "no id3 tag\n");
 275                 return;
 276         }
 277         *fpos = numbytes - 125;
 278         memcpy(mp3.id3.title, map + *fpos, 30);
 279         *fpos += 30;
 280         mp3.id3.title[30] = '\0';
 281         memcpy(mp3.id3.artist, map + *fpos, 30);
 282         *fpos += 30;
 283         mp3.id3.artist[30] = '\0';
 284         memcpy(mp3.id3.album, map + *fpos, 30);
 285         *fpos += 30;
 286         mp3.id3.album[30] = '\0';
 287         memcpy(mp3.id3.year, map + *fpos, 4);
 288         *fpos += 4;
 289         mp3.id3.year[4] = '\0';
 290         memcpy(mp3.id3.comment, map + *fpos, 30);
 291         mp3.id3.comment[30] = '\0';
 292         mp3.id3_isvalid = 1;
 293         unpad(mp3.id3.title);
 294         unpad(mp3.id3.artist);
 295         unpad(mp3.id3.album);
 296         unpad(mp3.id3.year);
 297         unpad(mp3.id3.comment);
 298 }
 299
 300 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos)
 301 {
 302         int frame_len;
 303
 304         frame_len = get_header(map, numbytes, fpos, &mp3.header);
 305         if (frame_len < 0)
 306                 return frame_len;
 307         if (!frame_len) {
 308                 frame_len = mp3_seek_next_header(map, numbytes, fpos);
 309                 if (frame_len <= 0)
 310                         return frame_len;
 311         } else
 312                 *fpos -= FRAME_HEADER_SIZE;
 313         if (frame_len <= 1)
 314                 return -E_FRAME_LENGTH;
 315         return frame_len;
 316 }
 317
 318 static int mp3_read_info(unsigned char *map, size_t numbytes,
 319                 struct audio_format_info *afi)
 320 {
 321         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 322         int ret, len = 0, old_br = -1;
 323         struct timeval total_time = {0, 0};
 324         unsigned chunk_table_size = 1000; /* gets increased on demand */
 325         off_t fpos = 0;
 326
 327         afi->chunks_total = 0;
 328         afi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 329         mp3_get_id3(map, numbytes, &fpos);
 330         fpos = 0;
 331         mp3.vbr = 0;
 332         while (1) {
 333                 unsigned long freq, br, fl;
 334                 struct timeval tmp, cct; /* current chunk time */
 335                 fpos += len;
 336                 len = find_valid_start(map, numbytes, &fpos);
 337                 if (len <= 0)
 338                         break;
 339                 ret = header_frequency(&mp3.header);
 340                 if (ret < 0)
 341                         continue;
 342                 freq = ret;
 343                 ret = header_bitrate(&mp3.header);
 344                 if (ret < 0)
 345                         continue;
 346                 br = ret;
 347                 ret = frame_length(&mp3.header);
 348                 if (ret < 0)
 349                         continue;
 350                 fl = ret;
 351                 tmp.tv_sec = fl;
 352                 tmp.tv_usec = 0;
 353                 tv_divide(br * 125, &tmp, &cct);
 354                 tv_add(&cct, &total_time, &tmp);
 355                 total_time = tmp;
 356                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 357                 if (afi->chunks_total >= chunk_table_size) {
 358                         chunk_table_size *= 2;
 359                         afi->chunk_table = para_realloc(afi->chunk_table,
 360                                 chunk_table_size * sizeof(size_t));
 361                 }
 362                 afi->chunk_table[afi->chunks_total] = fpos;
 363 //              if (afi->chunks_total < 10 || !(afi->chunks_total % 1000))
 364 //                      PARA_INFO_LOG("chunk #%lu: %zd\n", afi->chunks_total,
 365 //                              afi->chunk_table[afi->chunks_total]);
 366                 afi->chunks_total++;
 367                 if (afi->chunks_total == 1) {
 368                         freq_avg = freq;
 369                         br_avg = br;
 370                         old_br = br;
 371                         fl_avg = fl;
 372                         continue;
 373                 }
 374                 freq_avg += ((long)freq - freq_avg) / ((long)afi->chunks_total + 1);
 375                 fl_avg += ((long)fl - fl_avg) / ((long)afi->chunks_total + 1);
 376                 br_avg += ((long)br - br_avg) / ((long)afi->chunks_total + 1);
 377                 if (old_br != br)
 378                         mp3.vbr = 1;
 379                 old_br = br;
 380         }
 381         ret = -E_MP3_INFO;
 382         if (!afi->chunks_total || !freq_avg || !br_avg)
 383                 goto err_out;
 384         afi->chunk_table[afi->chunks_total] = numbytes - 1;
 385         afi->bitrate = br_avg;
 386         afi->frequency = freq_avg;
 387         afi->channels = header_channels(&mp3.header);
 388         afi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
 389         tv_divide(afi->chunks_total, &total_time, &afi->chunk_tv);
 390         PARA_DEBUG_LOG("%lu chunks, each %lums\n", afi->chunks_total,
 391                 tv2ms(&afi->chunk_tv));
 392         tv_scale(3, &afi->chunk_tv, &afi->eof_tv);
 393         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afi->eof_tv));
 394         return 1;
 395 err_out:
 396         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 397         free(afi->chunk_table);
 398         return ret;
 399 }
 400
 401 /*
 402  * Read mp3 information from audio file
 403  */
 404 int mp3_get_file_info(char *map, size_t numbytes,
 405                 struct audio_format_info *afi)
 406 {
 407         int ret;
 408
 409         ret = mp3_read_info((unsigned char *)map, numbytes, afi);
 410         if (ret < 0)
 411                 return ret;
 412         write_info_str(afi);
 413         if (afi->seconds_total < 2 || !afi->chunks_total)
 414                 return -E_MP3_INFO;
 415         return 1;
 416 }
 417
 418 static const char* mp3_suffixes[] = {"mp3", NULL};
 419
 420 /**
 421  * the init function of the mp3 audio format handler
 422  *
 423  * \param afh pointer to the struct to initialize
 424  */
 425 void mp3_init(struct audio_format_handler *afh)
 426 {
 427         afh->get_file_info = mp3_get_file_info;
 428         afh->suffixes = mp3_suffixes;
 429 }