mp3.c

   1 /*
   2  * Copyright (C) 2003-2006 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file mp3.c para_server's mp3 audio format handler */
  20
  21 /*
  22  * This file is based in part on mp3tech.c and mp3tech.h, Copyright (C)
  23  * 2000-2001 Cedric Tefft <cedric@earthling.net>, which in turn is based
  24  * in part on
  25  *
  26  *      * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
  27  *      * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and
  28  *                       Johannes Overmann <overmann@iname.com>
  29  */
  30
  31 #include "server.cmdline.h"
  32 #include "server.h"
  33 #include "afs.h"
  34 #include "error.h"
  35 #include "fd.h"
  36
  37 /** \cond some defines and structs which are only used in this file */
  38
  39 /*
  40  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  41  * to see before we decide we are looking at a real MP3 file
  42  */
  43 #define MIN_CONSEC_GOOD_FRAMES 3
  44
  45 #define FRAME_HEADER_SIZE 4
  46 #define MIN_FRAME_SIZE 21
  47
  48 struct mp3header {
  49         unsigned long sync;
  50         unsigned int version;
  51         unsigned int layer;
  52         unsigned int crc;
  53         unsigned int bitrate;
  54         unsigned int freq;
  55         unsigned int padding;
  56         unsigned int mode;
  57         unsigned int copyright;
  58         unsigned int original;
  59         unsigned int emphasis;
  60 };
  61
  62 struct id3tag {
  63         char title[31];
  64         char artist[31];
  65         char album[31];
  66         char year[5];
  67         char comment[31];
  68 };
  69
  70 struct mp3info {
  71         char *filename;
  72         FILE *file;
  73         struct mp3header header;
  74         int id3_isvalid;
  75         struct id3tag id3;
  76         int vbr;
  77         long unsigned br_average;
  78         long unsigned seconds;
  79         int frames;
  80         int freq;
  81 };
  82
  83 /** \endcond */
  84 static int frequencies[3][4] = {
  85         {22050,24000,16000,50000}, /* MPEG 2.0 */
  86         {44100,48000,32000,50000}, /* MPEG 1.0 */
  87         {11025,12000,8000,50000} /* MPEG 2.5 */
  88 };
  89
  90 static int mp3info_bitrate[2][3][14] = {
  91 { /* MPEG 2.0 */
  92         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  93         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  94         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  95 },
  96
  97 { /* MPEG 1.0 */
  98         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  99         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
 100         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
 101 }
 102 };
 103
 104 static int frame_size_index[] = {24000, 72000, 72000};
 105 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
 106
 107 static struct mp3info mp3;
 108 static char mp3buf[8192];
 109 static int chunk_size;
 110 static struct audio_format_handler *af;
 111
 112 static int header_frequency(struct mp3header *h)
 113 {
 114         if (h->version > 2 || h->freq > 3)
 115                 return -E_HEADER_FREQ;
 116         return frequencies[h->version][h->freq];
 117 }
 118
 119 static const char *header_mode(struct mp3header *h)
 120 {
 121         if (h->mode > 4)
 122                 h->mode = 4; /* invalid */
 123         return mode_text[h->mode];
 124 }
 125 static int header_bitrate(struct mp3header *h)
 126 {
 127         if (h->layer > 3 || h->bitrate > 14)
 128                 return -E_HEADER_BITRATE;
 129         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 130 }
 131
 132 static int frame_length(struct mp3header *header)
 133 {
 134         int hb, hf = header_frequency(header);
 135
 136         if (hf < 0)
 137                 return hf;
 138         hb = header_bitrate(header);
 139         if (hb < 0)
 140                 return hb;
 141         if (header->sync != 0xFFE || header->layer > 3)
 142                 return -E_FRAME;
 143         return frame_size_index[3 - header->layer] *
 144                 ((header->version & 1) + 1) * hb / hf
 145                 + header->padding;
 146 }
 147
 148 static void write_info_str(char *info_str)
 149 {
 150         int v = mp3.id3_isvalid;
 151
 152         snprintf(info_str, MMD_INFO_SIZE,
 153                 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
 154                 "audio_file_info2:%s, by %s\n"
 155                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 156                 mp3.frames,
 157                 tv2ms(&af->chunk_tv),
 158                 mp3.br_average,
 159                 mp3.vbr? 'v' : 'c',
 160                 mp3.freq / 1000,
 161                 header_mode(&mp3.header),
 162                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 163                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 164                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 165                 v && *mp3.id3.year? mp3.id3.year : "????",
 166                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 167         );
 168 }
 169
 170 /*
 171  * Remove trailing whitespace from the end of a string
 172  */
 173 static char *unpad(char *string)
 174 {
 175         char *pos = string + strlen(string) - 1;
 176         while (isspace(pos[0]))
 177                 (pos--)[0] = 0;
 178         return string;
 179 }
 180
 181 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 182 {
 183         if ((*(uint*)h1) == (*(uint*)h2))
 184                 return 1;
 185         if ((h1->version == h2->version) &&
 186                         (h1->layer == h2->layer) &&
 187                         (h1->crc == h2->crc) &&
 188                         (h1->freq == h2->freq) &&
 189                         (h1->mode == h2->mode) &&
 190                         (h1->copyright == h2->copyright) &&
 191                         (h1->original == h2->original) &&
 192                         (h1->emphasis == h2->emphasis))
 193                 return 1;
 194         else
 195                 return 0;
 196 }
 197
 198 /**
 199  * get next MP3 frame header.
 200  *
 201  * \param stream to read the header from
 202  * \param header structure that gets filled in by get_header()
 203  *
 204  * \return On success, the header frame length is returned.  A return value of
 205  * zero means that we did not retrieve a valid frame header, and a negative
 206  * return value indicates an error.
 207  */
 208 static int get_header(FILE *file, struct mp3header *header)
 209 {
 210         unsigned char buffer[FRAME_HEADER_SIZE];
 211         int fl, ret;
 212
 213         if (!file || !header)
 214                 return -E_MP3_NO_FILE;
 215         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 216         if (ret < FRAME_HEADER_SIZE) {
 217                 header->sync = 0;
 218                 return ret < 0? ret : 0;
 219         }
 220         header->layer = (buffer[1] >> 1) & 3;
 221         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 222         if (buffer[1] & 0x10)
 223                 header->version = (buffer[1] >> 3) & 1;
 224         else
 225                 header->version = 2;
 226         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 227                 header->sync = 0;
 228 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 229                 return 0;
 230         }
 231         header->crc = buffer[1] & 1;
 232         header->bitrate = (buffer[2] >> 4) & 0x0F;
 233 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 234 //              header->bitrate);
 235         header->freq = (buffer[2] >> 2) & 0x3;
 236         header->padding = (buffer[2] >>1) & 0x1;
 237         header->mode = (buffer[3] >> 6) & 0x3;
 238         fl = frame_length(header);
 239         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 240 }
 241
 242 /**
 243  * find the next mp3 header
 244  *
 245  * \return On success, the length of the next frame header. If the end of the
 246  * file was reached, the function returns zero. On errors, a negative value is
 247  * returned.
 248  *
 249  */
 250 static int mp3_seek_next_header(void)
 251 {
 252         int k, l = 0, c, first_len;
 253         struct mp3header h, h2;
 254         long valid_start = 0;
 255
 256         while (1) {
 257                 while ((c = fgetc(mp3.file)) != 255 && (c != EOF))
 258                         ; /* nothing */
 259                 if (c != 255)
 260                         return 0;
 261                 ungetc(c, mp3.file);
 262                 valid_start = ftell(mp3.file);
 263                 first_len = get_header(mp3.file, &h);
 264                 if (first_len <= 0)
 265                         continue;
 266                 if (fseek(mp3.file, first_len - FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 267                         return -E_FSEEK;
 268                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 269                         if ((l = get_header(mp3.file, &h2)) <= 0)
 270                                 break;
 271                         if (!compare_headers(&h, &h2))
 272                                 break;
 273                         fseek(mp3.file, l - FRAME_HEADER_SIZE, SEEK_CUR);
 274                 }
 275                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 276                         fseek(mp3.file, valid_start, SEEK_SET);
 277                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 278                         return first_len;
 279                 }
 280         }
 281 }
 282
 283 static int mp3_get_id3(void)
 284 {
 285         char fbuf[4];
 286
 287         mp3.id3_isvalid = 0;
 288         mp3.id3.title[0] = '\0';
 289         mp3.id3.artist[0] = '\0';
 290         mp3.id3.album[0] = '\0';
 291         mp3.id3.comment[0] = '\0';
 292         mp3.id3.year[0] = '\0';
 293         if (fseek(mp3.file, -128, SEEK_END))
 294                 return -E_FSEEK;
 295         if (para_fread(fbuf, 1, 3, mp3.file) < 0)
 296                 return -E_FREAD;
 297         fbuf[3] = '\0';
 298         if (strcmp("TAG", fbuf)) {
 299                 PARA_INFO_LOG("%s", "no id3 tag\n");
 300                 return 0;
 301         }
 302         if (fseek(mp3.file, -125, SEEK_END) < 0)
 303                 return -E_FSEEK;
 304         if (para_fread(mp3.id3.title, 1, 30, mp3.file) != 30)
 305                 return -E_FREAD;
 306         mp3.id3.title[30] = '\0';
 307         if (para_fread(mp3.id3.artist, 1, 30, mp3.file) != 30)
 308                 return -E_FREAD;
 309         mp3.id3.artist[30] = '\0';
 310         if (para_fread(mp3.id3.album, 1, 30, mp3.file) != 30)
 311                 return -E_FREAD;
 312         mp3.id3.album[30] = '\0';
 313         if (para_fread(mp3.id3.year, 1, 4, mp3.file) != 4)
 314                 return -E_FREAD;
 315         mp3.id3.year[4] = '\0';
 316         if (para_fread(mp3.id3.comment, 1, 30, mp3.file) != 30)
 317                 return -E_FREAD;
 318         mp3.id3.comment[30] = '\0';
 319         mp3.id3_isvalid = 1;
 320         unpad(mp3.id3.title);
 321         unpad(mp3.id3.artist);
 322         unpad(mp3.id3.album);
 323         unpad(mp3.id3.year);
 324         unpad(mp3.id3.comment);
 325         return 1;
 326 }
 327
 328 static int find_valid_start(void)
 329 {
 330         int frame_len;
 331
 332         if (!mp3.file)
 333                 return -E_MP3_NO_FILE;
 334         frame_len = get_header(mp3.file, &mp3.header);
 335         if (frame_len < 0)
 336                 return frame_len;
 337         if (!frame_len) {
 338                 frame_len = mp3_seek_next_header();
 339                 if (frame_len <= 0)
 340                         return frame_len;
 341         } else
 342                 if (fseek(mp3.file, -FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 343                         return -E_FSEEK;
 344         if (frame_len <= 1) /* FRAME_HEADER_SIZE? */
 345                 return -E_FRAME_LENGTH;
 346         return frame_len;
 347 }
 348
 349 static int mp3_read_info(void)
 350 {
 351         long fl_avg = 0, freq_avg = 0, br_avg = 0, fcount = 0;
 352         int ret, len = 0, old_br = -1;
 353         struct timeval total_time = {0, 0};
 354
 355         ret = mp3_get_id3();
 356         if (ret < 0)
 357                 return ret;
 358         rewind(mp3.file);
 359         mp3.vbr = 0;
 360         mp3.freq = 0;
 361         while (1) {
 362                 int freq, br, fl;
 363                 struct timeval tmp, cct; /* current chunk time */
 364                 if (len > 0)
 365                         if (fseek(mp3.file, len, SEEK_CUR) < 0)
 366                                 return -E_FSEEK;
 367                 len = find_valid_start();
 368                 if (len <= 0)
 369                         break;
 370                 freq = header_frequency(&mp3.header);
 371                 br = header_bitrate(&mp3.header);
 372                 fl = frame_length(&mp3.header);
 373                 if (freq < 0 || br < 0 || fl < 0)
 374                         continue;
 375                 tmp.tv_sec = fl;
 376                 tmp.tv_usec = 0;
 377                 tv_divide(br * 125, &tmp, &cct);
 378                 tv_add(&cct, &total_time, &tmp);
 379                 total_time = tmp;
 380 //              PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 381                 fcount++;
 382                 if (fcount == 1) {
 383                         freq_avg = freq;
 384                         br_avg = br;
 385                         old_br = br;
 386                         fl_avg = fl;
 387                         continue;
 388                 }
 389                 freq_avg += (freq - freq_avg) / (fcount + 1);
 390                 fl_avg += (fl - fl_avg) / (fcount + 1);
 391                 br_avg += (br - br_avg) / (fcount + 1);
 392                 if (old_br != br)
 393                         mp3.vbr = 1;
 394                 old_br = br;
 395         }
 396         if (!fcount || !freq_avg || !br_avg)
 397                 return -E_MP3_INFO;
 398         mp3.br_average = br_avg;
 399         mp3.freq = freq_avg;
 400         mp3.frames = fcount;
 401         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 402         tv_divide(fcount, &total_time, &af->chunk_tv);
 403         rewind(mp3.file);
 404         PARA_DEBUG_LOG("chunk_time: %lums\n", tv2ms(&af->chunk_tv));
 405         tv_scale(30, &af->chunk_tv, &af->eof_tv);
 406         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&af->eof_tv));
 407         return 1;
 408 }
 409
 410 /*
 411  * Read mp3 information from audio file
 412  */
 413 static int mp3_get_file_info(FILE *audio_file, char *info_str,
 414         long unsigned *frames, int *seconds)
 415 {
 416         int ret;
 417
 418         if (!audio_file)
 419                 return -E_MP3_NO_FILE;
 420         mp3.file = audio_file;
 421         ret = mp3_read_info();
 422         if (ret < 0) {
 423                 mp3.file = NULL;
 424                 return ret;
 425         }
 426         write_info_str(info_str);
 427         *frames = mp3.frames;
 428         *seconds = mp3.seconds;
 429         if (*seconds < 2 || !*frames)
 430                 return -E_MP3_INFO;
 431         return 1;
 432 }
 433
 434 static int mp3_reposition_stream(long unsigned new_frame)
 435 {
 436         int count = 0, len;
 437
 438         PARA_DEBUG_LOG("jmp to frame %lu/%i\n", new_frame, mp3.frames);
 439         rewind(mp3.file);
 440         while (count < new_frame && (len = find_valid_start()) > 0) {
 441 //              PARA_DEBUG_LOG("%s: jmp to frame %d\n", __func__, count);
 442                 if (fseek(mp3.file, len, SEEK_CUR) < 0)
 443                         return -E_FSEEK;
 444                 count++;
 445         }
 446         if (count != new_frame) {
 447                 rewind(mp3.file);
 448                 return -E_MP3_REPOS;
 449         }
 450         return 1;
 451 }
 452
 453 static int mp3_read_next_chunk(void)
 454 {
 455         int len = find_valid_start();
 456
 457         if (len <= 0) {
 458                 if (len < 0)
 459                         PARA_ERROR_LOG("invalid frame len (%d)\n", len);
 460                 return len;
 461         }
 462         chunk_size = para_fread(mp3buf, len, 1, mp3.file);
 463         if (len != chunk_size)
 464                 PARA_DEBUG_LOG("short read (%d/%d)\n", chunk_size, len);
 465         return chunk_size;
 466 }
 467
 468 static char *mp3_read_chunk(__a_unused long unsigned chunk_num, ssize_t *len)
 469 {
 470         *len = mp3_read_next_chunk();
 471         if (*len <= 0)
 472                 return NULL;
 473         return mp3buf;
 474 }
 475
 476 static void mp3_close_audio_file(void)
 477 {
 478         if (!mp3.file)
 479                 return;
 480         fclose(mp3.file);
 481         mp3.file = NULL;
 482 }
 483
 484 static const char* mp3_suffixes[] = {"mp3", NULL};
 485 void mp3_init(struct audio_format_handler *p)
 486 {
 487         af = p;
 488         af->get_file_info = mp3_get_file_info;
 489         af->reposition_stream = mp3_reposition_stream;
 490         af->read_chunk = mp3_read_chunk;
 491         af->close_audio_file = mp3_close_audio_file;
 492         af->get_header_info = NULL;
 493         /* eof_tv gets overwritten in mp3_get_file_info() */
 494         af->eof_tv.tv_sec = 0;
 495         af->eof_tv.tv_usec = 100 * 1000;
 496         af->suffixes = mp3_suffixes;
 497 }