mp3_afh.c

   1 /*
   2  * Copyright (C) 2003-2007 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_afh.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 "vss.h"
  34 #include "afh.h"
  35 #include "error.h"
  36 #include "fd.h"
  37 #include "string.h"
  38
  39 /** \cond some defines and structs which are only used in this file */
  40
  41 /*
  42  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  43  * to see before we decide we are looking at a real MP3 file
  44  */
  45 #define MIN_CONSEC_GOOD_FRAMES 4
  46
  47 #define FRAME_HEADER_SIZE 4
  48 #define MIN_FRAME_SIZE 21
  49 #define DEFAULT_INBUF_SIZE 8192
  50
  51 struct mp3header {
  52         unsigned long sync;
  53         unsigned int version;
  54         unsigned int layer;
  55         unsigned int crc;
  56         unsigned int bitrate;
  57         unsigned int freq;
  58         unsigned int padding;
  59         unsigned int mode;
  60         unsigned int copyright;
  61         unsigned int original;
  62         unsigned int emphasis;
  63 };
  64
  65 struct id3tag {
  66         char title[31];
  67         char artist[31];
  68         char album[31];
  69         char year[5];
  70         char comment[31];
  71 };
  72
  73 struct mp3info {
  74         char *filename;
  75         struct mp3header header;
  76         int id3_isvalid;
  77         struct id3tag id3;
  78         int vbr;
  79         long unsigned br_average;
  80         long unsigned seconds;
  81         int freq;
  82 };
  83
  84 /** \endcond */
  85 static int frequencies[3][4] = {
  86         {22050,24000,16000,50000}, /* MPEG 2.0 */
  87         {44100,48000,32000,50000}, /* MPEG 1.0 */
  88         {11025,12000,8000,50000} /* MPEG 2.5 */
  89 };
  90
  91 static int mp3info_bitrate[2][3][14] = {
  92 { /* MPEG 2.0 */
  93         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  94         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  95         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  96 },
  97
  98 { /* MPEG 1.0 */
  99         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
 100         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
 101         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
 102 }
 103 };
 104
 105 static int frame_size_index[] = {24000, 72000, 72000};
 106 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
 107
 108 static FILE *infile;
 109 static struct mp3info mp3;
 110 static char *inbuf;
 111 static size_t inbuf_size;
 112 static struct audio_format_handler *af;
 113 static ssize_t *chunk_table, num_chunks;
 114
 115 static int header_frequency(struct mp3header *h)
 116 {
 117         if (h->version > 2 || h->freq > 3)
 118                 return -E_HEADER_FREQ;
 119         return frequencies[h->version][h->freq];
 120 }
 121
 122 static const char *header_mode(struct mp3header *h)
 123 {
 124         if (h->mode > 4)
 125                 h->mode = 4; /* invalid */
 126         return mode_text[h->mode];
 127 }
 128 static int header_bitrate(struct mp3header *h)
 129 {
 130         if (h->layer > 3 || h->bitrate > 14)
 131                 return -E_HEADER_BITRATE;
 132         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 133 }
 134
 135 static int frame_length(struct mp3header *header)
 136 {
 137         int hb, hf = header_frequency(header);
 138
 139         if (hf < 0)
 140                 return hf;
 141         hb = header_bitrate(header);
 142         if (hb < 0)
 143                 return hb;
 144         if (header->sync != 0xFFE || header->layer > 3)
 145                 return -E_FRAME;
 146         return frame_size_index[3 - header->layer] *
 147                 ((header->version & 1) + 1) * hb / hf
 148                 + header->padding;
 149 }
 150
 151 static void write_info_str(char *info_str)
 152 {
 153         int v = mp3.id3_isvalid;
 154
 155         snprintf(info_str, MMD_INFO_SIZE,
 156                 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
 157                 "audio_file_info2:%s, by %s\n"
 158                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 159                 num_chunks,
 160                 tv2ms(&af->chunk_tv),
 161                 mp3.br_average,
 162                 mp3.vbr? 'v' : 'c',
 163                 mp3.freq / 1000,
 164                 header_mode(&mp3.header),
 165                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 166                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 167                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 168                 v && *mp3.id3.year? mp3.id3.year : "????",
 169                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 170         );
 171 }
 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 (isspace(pos[0]))
 180                 (pos--)[0] = 0;
 181         return string;
 182 }
 183
 184 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 185 {
 186         if ((*(uint*)h1) == (*(uint*)h2))
 187                 return 1;
 188         if ((h1->version == h2->version) &&
 189                         (h1->layer == h2->layer) &&
 190                         (h1->crc == h2->crc) &&
 191                         (h1->freq == h2->freq) &&
 192                         (h1->mode == h2->mode) &&
 193                         (h1->copyright == h2->copyright) &&
 194                         (h1->original == h2->original) &&
 195                         (h1->emphasis == h2->emphasis))
 196                 return 1;
 197         else
 198                 return 0;
 199 }
 200
 201 /**
 202  * get next MP3 frame header.
 203  *
 204  * \param stream to read the header from
 205  * \param header structure that gets filled in by get_header()
 206  *
 207  * \return On success, the header frame length is returned.  A return value of
 208  * zero means that we did not retrieve a valid frame header, and a negative
 209  * return value indicates an error.
 210  */
 211 static int get_header(FILE *file, struct mp3header *header)
 212 {
 213         unsigned char buffer[FRAME_HEADER_SIZE];
 214         int fl, ret;
 215
 216         if (!file || !header)
 217                 return -E_MP3_NO_FILE;
 218         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 219         if (ret < FRAME_HEADER_SIZE) {
 220                 header->sync = 0;
 221                 return ret < 0? ret : 0;
 222         }
 223         header->layer = (buffer[1] >> 1) & 3;
 224         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 225         if (buffer[1] & 0x10)
 226                 header->version = (buffer[1] >> 3) & 1;
 227         else
 228                 header->version = 2;
 229         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 230                 header->sync = 0;
 231 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 232                 return 0;
 233         }
 234         header->crc = buffer[1] & 1;
 235         header->bitrate = (buffer[2] >> 4) & 0x0F;
 236 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 237 //              header->bitrate);
 238         header->freq = (buffer[2] >> 2) & 0x3;
 239         header->padding = (buffer[2] >>1) & 0x1;
 240         header->mode = (buffer[3] >> 6) & 0x3;
 241         fl = frame_length(header);
 242         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 243 }
 244
 245 /**
 246  * find the next mp3 header
 247  *
 248  * \return On success, the length of the next frame header. If the end of the
 249  * file was reached, the function returns zero. On errors, a negative value is
 250  * returned.
 251  *
 252  */
 253 static int mp3_seek_next_header(void)
 254 {
 255         int k, l = 0, c, first_len;
 256         struct mp3header h, h2;
 257         long valid_start = 0;
 258
 259         while (1) {
 260                 while ((c = fgetc(infile)) != 255 && (c != EOF))
 261                         ; /* nothing */
 262                 if (c != 255)
 263                         return 0;
 264                 ungetc(c, infile);
 265                 valid_start = ftell(infile);
 266                 first_len = get_header(infile, &h);
 267                 if (first_len <= 0)
 268                         continue;
 269                 if (fseek(infile, first_len - FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 270                         return -E_FSEEK;
 271                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 272                         if ((l = get_header(infile, &h2)) <= 0)
 273                                 break;
 274                         if (!compare_headers(&h, &h2))
 275                                 break;
 276                         fseek(infile, l - FRAME_HEADER_SIZE, SEEK_CUR);
 277                 }
 278                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 279                         fseek(infile, valid_start, SEEK_SET);
 280                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 281                         return first_len;
 282                 }
 283         }
 284 }
 285
 286 static int mp3_get_id3(void)
 287 {
 288         char fbuf[4];
 289
 290         mp3.id3_isvalid = 0;
 291         mp3.id3.title[0] = '\0';
 292         mp3.id3.artist[0] = '\0';
 293         mp3.id3.album[0] = '\0';
 294         mp3.id3.comment[0] = '\0';
 295         mp3.id3.year[0] = '\0';
 296         if (fseek(infile, -128, SEEK_END))
 297                 return -E_FSEEK;
 298         if (para_fread(fbuf, 1, 3, infile) < 0)
 299                 return -E_FREAD;
 300         fbuf[3] = '\0';
 301         if (strcmp("TAG", fbuf)) {
 302                 PARA_INFO_LOG("%s", "no id3 tag\n");
 303                 return 0;
 304         }
 305         if (fseek(infile, -125, SEEK_END) < 0)
 306                 return -E_FSEEK;
 307         if (para_fread(mp3.id3.title, 1, 30, infile) != 30)
 308                 return -E_FREAD;
 309         mp3.id3.title[30] = '\0';
 310         if (para_fread(mp3.id3.artist, 1, 30, infile) != 30)
 311                 return -E_FREAD;
 312         mp3.id3.artist[30] = '\0';
 313         if (para_fread(mp3.id3.album, 1, 30, infile) != 30)
 314                 return -E_FREAD;
 315         mp3.id3.album[30] = '\0';
 316         if (para_fread(mp3.id3.year, 1, 4, infile) != 4)
 317                 return -E_FREAD;
 318         mp3.id3.year[4] = '\0';
 319         if (para_fread(mp3.id3.comment, 1, 30, infile) != 30)
 320                 return -E_FREAD;
 321         mp3.id3.comment[30] = '\0';
 322         mp3.id3_isvalid = 1;
 323         unpad(mp3.id3.title);
 324         unpad(mp3.id3.artist);
 325         unpad(mp3.id3.album);
 326         unpad(mp3.id3.year);
 327         unpad(mp3.id3.comment);
 328         return 1;
 329 }
 330
 331 static int find_valid_start(void)
 332 {
 333         int frame_len;
 334
 335         if (!infile)
 336                 return -E_MP3_NO_FILE;
 337         frame_len = get_header(infile, &mp3.header);
 338         if (frame_len < 0)
 339                 return frame_len;
 340         if (!frame_len) {
 341                 frame_len = mp3_seek_next_header();
 342                 if (frame_len <= 0)
 343                         return frame_len;
 344         } else
 345                 if (fseek(infile, -FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 346                         return -E_FSEEK;
 347         if (frame_len <= 1)
 348                 return -E_FRAME_LENGTH;
 349         return frame_len;
 350 }
 351
 352 static int mp3_read_info(void)
 353 {
 354         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 355         int ret, len = 0, old_br = -1;
 356         struct timeval total_time = {0, 0};
 357         unsigned chunk_table_size = 1000; /* gets increased on demand */
 358
 359         num_chunks = 0;
 360         inbuf = para_malloc(DEFAULT_INBUF_SIZE);
 361         inbuf_size = DEFAULT_INBUF_SIZE;
 362         chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 363         ret = mp3_get_id3();
 364         if (ret < 0)
 365                 goto err_out;
 366         rewind(infile);
 367         mp3.vbr = 0;
 368         mp3.freq = 0;
 369         while (1) {
 370                 int freq, br, fl;
 371                 struct timeval tmp, cct; /* current chunk time */
 372                 if (len > 0) {
 373                         ret = -E_FSEEK;
 374                         if (fseek(infile, len, SEEK_CUR) < 0)
 375                                 goto err_out;
 376                 }
 377                 len = find_valid_start();
 378                 if (len <= 0)
 379                         break;
 380                 freq = header_frequency(&mp3.header);
 381                 br = header_bitrate(&mp3.header);
 382                 fl = frame_length(&mp3.header);
 383                 if (freq < 0 || br < 0 || fl < 0)
 384                         continue;
 385                 tmp.tv_sec = fl;
 386                 tmp.tv_usec = 0;
 387                 tv_divide(br * 125, &tmp, &cct);
 388                 tv_add(&cct, &total_time, &tmp);
 389                 total_time = tmp;
 390                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 391                 if (num_chunks >= chunk_table_size) {
 392                         chunk_table_size *= 2;
 393                         chunk_table = para_realloc(chunk_table,
 394                                 chunk_table_size * sizeof(size_t));
 395                 }
 396                 chunk_table[num_chunks] = ftell(infile);
 397                 if (num_chunks < 10 || !(num_chunks % 1000))
 398                         PARA_INFO_LOG("chunk #%d: %zd\n", num_chunks,
 399                                 chunk_table[num_chunks]);
 400                 num_chunks++;
 401                 if (num_chunks == 1) {
 402 //                      entry = ftell(infile);
 403 //                      PARA_INFO_LOG("entry: %zd\n", entry);
 404                         freq_avg = freq;
 405                         br_avg = br;
 406                         old_br = br;
 407                         fl_avg = fl;
 408                         continue;
 409                 }
 410                 freq_avg += (freq - freq_avg) / (num_chunks + 1);
 411                 fl_avg += (fl - fl_avg) / (num_chunks + 1);
 412                 br_avg += (br - br_avg) / (num_chunks + 1);
 413                 if (old_br != br)
 414                         mp3.vbr = 1;
 415                 old_br = br;
 416         }
 417         ret = -E_MP3_INFO;
 418         if (!num_chunks || !freq_avg || !br_avg)
 419                 goto err_out;
 420         ret = -E_FSEEK;
 421         if (fseek(infile, 0, SEEK_END) < 0)
 422                 goto err_out;
 423         chunk_table[num_chunks] = ftell(infile);
 424         mp3.br_average = br_avg;
 425         mp3.freq = freq_avg;
 426         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 427         tv_divide(num_chunks, &total_time, &af->chunk_tv);
 428         rewind(infile);
 429         PARA_DEBUG_LOG("%zu chunks, each %lums\n", num_chunks, tv2ms(&af->chunk_tv));
 430         tv_scale(3, &af->chunk_tv, &af->eof_tv);
 431         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&af->eof_tv));
 432         return 1;
 433 err_out:
 434         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 435         free(chunk_table);
 436         free(inbuf);
 437         return ret;
 438 }
 439
 440 /*
 441  * Read mp3 information from audio file
 442  */
 443 static int mp3_get_file_info(FILE *audio_file, char *info_str,
 444         long unsigned *frames, int *seconds, size_t **vss_chunk_table)
 445 {
 446         int ret;
 447
 448         if (!audio_file)
 449                 return -E_MP3_NO_FILE;
 450         infile = audio_file;
 451         ret = mp3_read_info();
 452         if (ret < 0) {
 453                 infile = NULL;
 454                 return ret;
 455         }
 456         write_info_str(info_str);
 457         *frames = num_chunks;
 458         *seconds = mp3.seconds;
 459         *vss_chunk_table = chunk_table;
 460         if (*seconds < 2 || !*frames)
 461                 return -E_MP3_INFO;
 462         return 1;
 463 }
 464
 465 static char *mp3_read_chunk(long unsigned current_chunk, ssize_t *len)
 466 {
 467         int ret;
 468         size_t pos;
 469
 470         *len = 0;
 471         if (current_chunk >= num_chunks)
 472                 return NULL;
 473         *len = chunk_table[current_chunk + 1] - chunk_table[current_chunk];
 474         if (!*len) /* nothing to send for this run */
 475                 return inbuf;
 476         pos = chunk_table[current_chunk];
 477         if (inbuf_size < *len) {
 478                 PARA_INFO_LOG("increasing inbuf for chunk #%lu/%zu to %zd bytes\n",
 479                         current_chunk, num_chunks, *len);
 480                 inbuf = para_realloc(inbuf, *len);
 481                 inbuf_size = *len;
 482         }
 483 //      PARA_DEBUG_LOG("reading chunk #%lu@%zd (%zd bytes)\n", current_chunk,
 484 //              pos, *len);
 485         ret = fseek(infile, pos, SEEK_SET);
 486         if (ret < 0)
 487                 return NULL;
 488         ret = para_fread(inbuf, *len, 1, infile);
 489         if (ret != *len)
 490                 return NULL;
 491 //      PARA_DEBUG_LOG("ret: %d, inbuf[0]: %lx - %lx\n", ret, (long unsigned) inbuf[0],
 492 //              (long unsigned) inbuf[4]);
 493         return (char *)inbuf;
 494 }
 495
 496 static void mp3_close_audio_file(void)
 497 {
 498         if (!infile)
 499                 return;
 500         fclose(infile);
 501         infile = NULL;
 502         free(chunk_table);
 503         free(inbuf);
 504 }
 505
 506 static const char* mp3_suffixes[] = {"mp3", NULL};
 507
 508 /**
 509  * the init function of the mp3 audio format handler
 510  *
 511  * \param p pointer to the struct to initialize
 512  */
 513 void mp3_init(struct audio_format_handler *p)
 514 {
 515         af = p;
 516         af->get_file_info = mp3_get_file_info;
 517         af->read_chunk = mp3_read_chunk;
 518         af->close_audio_file = mp3_close_audio_file;
 519         af->get_header_info = NULL;
 520         /* eof_tv gets overwritten in mp3_get_file_info() */
 521         af->eof_tv.tv_sec = 0;
 522         af->eof_tv.tv_usec = 100 * 1000;
 523         af->suffixes = mp3_suffixes;
 524 }