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
  50 struct mp3header {
  51         unsigned long sync;
  52         unsigned int version;
  53         unsigned int layer;
  54         unsigned int crc;
  55         unsigned int bitrate;
  56         unsigned int freq;
  57         unsigned int padding;
  58         unsigned int mode;
  59         unsigned int copyright;
  60         unsigned int original;
  61         unsigned int emphasis;
  62 };
  63
  64 struct id3tag {
  65         char title[31];
  66         char artist[31];
  67         char album[31];
  68         char year[5];
  69         char comment[31];
  70 };
  71
  72 struct mp3info {
  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 freq;
  80 };
  81
  82 /** \endcond */
  83 static const int frequencies[3][4] = {
  84         {22050,24000,16000,50000}, /* MPEG 2.0 */
  85         {44100,48000,32000,50000}, /* MPEG 1.0 */
  86         {11025,12000,8000,50000} /* MPEG 2.5 */
  87 };
  88
  89 static const int mp3info_bitrate[2][3][14] = {
  90 { /* MPEG 2.0 */
  91         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  92         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  93         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  94 },
  95
  96 { /* MPEG 1.0 */
  97         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  98         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  99         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
 100 }
 101 };
 102
 103 static const int frame_size_index[] = {24000, 72000, 72000};
 104 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
 105
 106 static FILE *infile;
 107 static struct mp3info mp3;
 108 static struct audio_format_handler *af;
 109 static ssize_t *chunk_table, num_chunks;
 110
 111 static int header_frequency(struct mp3header *h)
 112 {
 113         if (h->version > 2 || h->freq > 3)
 114                 return -E_HEADER_FREQ;
 115         return frequencies[h->version][h->freq];
 116 }
 117
 118 static const char *header_mode(struct mp3header *h)
 119 {
 120         if (h->mode > 4)
 121                 h->mode = 4; /* invalid */
 122         return mode_text[h->mode];
 123 }
 124 static int header_bitrate(struct mp3header *h)
 125 {
 126         if (h->layer > 3 || h->bitrate > 14)
 127                 return -E_HEADER_BITRATE;
 128         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 129 }
 130
 131 static int frame_length(struct mp3header *header)
 132 {
 133         int hb, hf = header_frequency(header);
 134
 135         if (hf < 0)
 136                 return hf;
 137         hb = header_bitrate(header);
 138         if (hb < 0)
 139                 return hb;
 140         if (header->sync != 0xFFE || header->layer > 3)
 141                 return -E_FRAME;
 142         return frame_size_index[3 - header->layer] *
 143                 ((header->version & 1) + 1) * hb / hf
 144                 + header->padding;
 145 }
 146
 147 static void write_info_str(char *info_str)
 148 {
 149         int v = mp3.id3_isvalid;
 150
 151         snprintf(info_str, MMD_INFO_SIZE,
 152                 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
 153                 "audio_file_info2:%s, by %s\n"
 154                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 155                 num_chunks,
 156                 tv2ms(&af->chunk_tv),
 157                 mp3.br_average,
 158                 mp3.vbr? 'v' : 'c',
 159                 mp3.freq / 1000,
 160                 header_mode(&mp3.header),
 161                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 162                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 163                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 164                 v && *mp3.id3.year? mp3.id3.year : "????",
 165                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 166         );
 167 }
 168
 169 /*
 170  * Remove trailing whitespace from the end of a string
 171  */
 172 static char *unpad(char *string)
 173 {
 174         char *pos = string + strlen(string) - 1;
 175         while (isspace(pos[0]))
 176                 (pos--)[0] = 0;
 177         return string;
 178 }
 179
 180 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 181 {
 182         if ((*(uint*)h1) == (*(uint*)h2))
 183                 return 1;
 184         if ((h1->version == h2->version) &&
 185                         (h1->layer == h2->layer) &&
 186                         (h1->crc == h2->crc) &&
 187                         (h1->freq == h2->freq) &&
 188                         (h1->mode == h2->mode) &&
 189                         (h1->copyright == h2->copyright) &&
 190                         (h1->original == h2->original) &&
 191                         (h1->emphasis == h2->emphasis))
 192                 return 1;
 193         return 0;
 194 }
 195
 196 /**
 197  * get next MP3 frame header.
 198  *
 199  * \param stream to read the header from
 200  * \param header structure that gets filled in by get_header()
 201  *
 202  * \return On success, the header frame length is returned.  A return value of
 203  * zero means that we did not retrieve a valid frame header, and a negative
 204  * return value indicates an error.
 205  */
 206 static int get_header(FILE *file, struct mp3header *header)
 207 {
 208         unsigned char buffer[FRAME_HEADER_SIZE];
 209         int fl, ret;
 210
 211         if (!file || !header)
 212                 return -E_MP3_NO_FILE;
 213         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 214         if (ret < FRAME_HEADER_SIZE) {
 215                 header->sync = 0;
 216                 return ret < 0? ret : 0;
 217         }
 218         header->layer = (buffer[1] >> 1) & 3;
 219         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 220         if (buffer[1] & 0x10)
 221                 header->version = (buffer[1] >> 3) & 1;
 222         else
 223                 header->version = 2;
 224         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 225                 header->sync = 0;
 226 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 227                 return 0;
 228         }
 229         header->crc = buffer[1] & 1;
 230         header->bitrate = (buffer[2] >> 4) & 0x0F;
 231 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 232 //              header->bitrate);
 233         header->freq = (buffer[2] >> 2) & 0x3;
 234         header->padding = (buffer[2] >>1) & 0x1;
 235         header->mode = (buffer[3] >> 6) & 0x3;
 236         fl = frame_length(header);
 237         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 238 }
 239
 240 /**
 241  * find the next mp3 header
 242  *
 243  * \return On success, the length of the next frame header. If the end of the
 244  * file was reached, the function returns zero. On errors, a negative value is
 245  * returned.
 246  *
 247  */
 248 static int mp3_seek_next_header(void)
 249 {
 250         int k, l = 0, c, first_len, ret;
 251         struct mp3header h, h2;
 252         long valid_start = 0;
 253
 254         while (1) {
 255                 while ((c = fgetc(infile)) != 255 && (c != EOF))
 256                         ; /* nothing */
 257                 if (c != 255)
 258                         return 0;
 259                 ungetc(c, infile);
 260                 valid_start = ftell(infile);
 261                 first_len = get_header(infile, &h);
 262                 if (first_len <= 0)
 263                         continue;
 264                 ret = para_fseek(infile, first_len - FRAME_HEADER_SIZE, SEEK_CUR);
 265                 if (ret < 0)
 266                         return ret;
 267                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 268                         if ((l = get_header(infile, &h2)) <= 0)
 269                                 break;
 270                         if (!compare_headers(&h, &h2))
 271                                 break;
 272                         ret = para_fseek(infile, l - FRAME_HEADER_SIZE, SEEK_CUR);
 273                         if (ret < 0)
 274                                 return ret;
 275                 }
 276                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 277                         ret = para_fseek(infile, valid_start, SEEK_SET);
 278                         if (ret < 0)
 279                                 return ret;
 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         int ret;
 290
 291         mp3.id3_isvalid = 0;
 292         mp3.id3.title[0] = '\0';
 293         mp3.id3.artist[0] = '\0';
 294         mp3.id3.album[0] = '\0';
 295         mp3.id3.comment[0] = '\0';
 296         mp3.id3.year[0] = '\0';
 297         ret = para_fseek(infile, -128, SEEK_END);
 298         if (ret < 0 )
 299                 return ret;
 300         if (para_fread(fbuf, 1, 3, infile) < 0)
 301                 return -E_FREAD;
 302         fbuf[3] = '\0';
 303         if (strcmp("TAG", fbuf)) {
 304                 PARA_INFO_LOG("%s", "no id3 tag\n");
 305                 return 0;
 306         }
 307         ret = para_fseek(infile, -125, SEEK_END);
 308         if (ret < 0)
 309                 return ret;
 310         if (para_fread(mp3.id3.title, 1, 30, infile) != 30)
 311                 return -E_FREAD;
 312         mp3.id3.title[30] = '\0';
 313         if (para_fread(mp3.id3.artist, 1, 30, infile) != 30)
 314                 return -E_FREAD;
 315         mp3.id3.artist[30] = '\0';
 316         if (para_fread(mp3.id3.album, 1, 30, infile) != 30)
 317                 return -E_FREAD;
 318         mp3.id3.album[30] = '\0';
 319         if (para_fread(mp3.id3.year, 1, 4, infile) != 4)
 320                 return -E_FREAD;
 321         mp3.id3.year[4] = '\0';
 322         if (para_fread(mp3.id3.comment, 1, 30, infile) != 30)
 323                 return -E_FREAD;
 324         mp3.id3.comment[30] = '\0';
 325         mp3.id3_isvalid = 1;
 326         unpad(mp3.id3.title);
 327         unpad(mp3.id3.artist);
 328         unpad(mp3.id3.album);
 329         unpad(mp3.id3.year);
 330         unpad(mp3.id3.comment);
 331         return 1;
 332 }
 333
 334 static int find_valid_start(void)
 335 {
 336         int ret, frame_len;
 337
 338         if (!infile)
 339                 return -E_MP3_NO_FILE;
 340         frame_len = get_header(infile, &mp3.header);
 341         if (frame_len < 0)
 342                 return frame_len;
 343         if (!frame_len) {
 344                 frame_len = mp3_seek_next_header();
 345                 if (frame_len <= 0)
 346                         return frame_len;
 347         } else {
 348                 ret = para_fseek(infile, -FRAME_HEADER_SIZE, SEEK_CUR);
 349                 if (ret < 0)
 350                         return ret;
 351         }
 352         if (frame_len <= 1)
 353                 return -E_FRAME_LENGTH;
 354         return frame_len;
 355 }
 356
 357 static int mp3_read_info(void)
 358 {
 359         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 360         int ret, len = 0, old_br = -1;
 361         struct timeval total_time = {0, 0};
 362         unsigned chunk_table_size = 1000; /* gets increased on demand */
 363
 364         num_chunks = 0;
 365         chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 366         ret = mp3_get_id3();
 367         if (ret < 0)
 368                 goto err_out;
 369         rewind(infile);
 370         mp3.vbr = 0;
 371         mp3.freq = 0;
 372         while (1) {
 373                 int freq, br, fl;
 374                 struct timeval tmp, cct; /* current chunk time */
 375                 if (len > 0) {
 376                         ret = para_fseek(infile, len, SEEK_CUR);
 377                         if (ret < 0)
 378                                 goto err_out;
 379                 }
 380                 len = find_valid_start();
 381                 if (len <= 0)
 382                         break;
 383                 freq = header_frequency(&mp3.header);
 384                 br = header_bitrate(&mp3.header);
 385                 fl = frame_length(&mp3.header);
 386                 if (freq < 0 || br < 0 || fl < 0)
 387                         continue;
 388                 tmp.tv_sec = fl;
 389                 tmp.tv_usec = 0;
 390                 tv_divide(br * 125, &tmp, &cct);
 391                 tv_add(&cct, &total_time, &tmp);
 392                 total_time = tmp;
 393                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 394                 if (num_chunks >= chunk_table_size) {
 395                         chunk_table_size *= 2;
 396                         chunk_table = para_realloc(chunk_table,
 397                                 chunk_table_size * sizeof(size_t));
 398                 }
 399                 chunk_table[num_chunks] = ftell(infile);
 400                 if (num_chunks < 10 || !(num_chunks % 1000))
 401                         PARA_INFO_LOG("chunk #%d: %zd\n", num_chunks,
 402                                 chunk_table[num_chunks]);
 403                 num_chunks++;
 404                 if (num_chunks == 1) {
 405 //                      entry = ftell(infile);
 406 //                      PARA_INFO_LOG("entry: %zd\n", entry);
 407                         freq_avg = freq;
 408                         br_avg = br;
 409                         old_br = br;
 410                         fl_avg = fl;
 411                         continue;
 412                 }
 413                 freq_avg += (freq - freq_avg) / (num_chunks + 1);
 414                 fl_avg += (fl - fl_avg) / (num_chunks + 1);
 415                 br_avg += (br - br_avg) / (num_chunks + 1);
 416                 if (old_br != br)
 417                         mp3.vbr = 1;
 418                 old_br = br;
 419         }
 420         ret = -E_MP3_INFO;
 421         if (!num_chunks || !freq_avg || !br_avg)
 422                 goto err_out;
 423         ret= para_fseek(infile, 0, SEEK_END);
 424         if (ret < 0)
 425                 goto err_out;
 426         chunk_table[num_chunks] = ftell(infile);
 427         mp3.br_average = br_avg;
 428         mp3.freq = freq_avg;
 429         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 430         tv_divide(num_chunks, &total_time, &af->chunk_tv);
 431         rewind(infile);
 432         PARA_DEBUG_LOG("%zu chunks, each %lums\n", num_chunks, tv2ms(&af->chunk_tv));
 433         tv_scale(3, &af->chunk_tv, &af->eof_tv);
 434         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&af->eof_tv));
 435         return 1;
 436 err_out:
 437         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 438         free(chunk_table);
 439         return ret;
 440 }
 441
 442 /*
 443  * Read mp3 information from audio file
 444  */
 445 static int mp3_get_file_info(FILE *audio_file, char *info_str,
 446         long unsigned *frames, int *seconds, size_t **vss_chunk_table)
 447 {
 448         int ret;
 449
 450         if (!audio_file)
 451                 return -E_MP3_NO_FILE;
 452         infile = audio_file;
 453         ret = mp3_read_info();
 454         if (ret < 0) {
 455                 infile = NULL;
 456                 return ret;
 457         }
 458         write_info_str(info_str);
 459         *frames = num_chunks;
 460         *seconds = mp3.seconds;
 461         *vss_chunk_table = chunk_table;
 462         if (*seconds < 2 || !*frames)
 463                 return -E_MP3_INFO;
 464         return 1;
 465 }
 466
 467 static void mp3_close_audio_file(void)
 468 {
 469         if (!infile)
 470                 return;
 471         fclose(infile);
 472         infile = NULL;
 473         free(chunk_table);
 474 }
 475
 476 static const char* mp3_suffixes[] = {"mp3", NULL};
 477
 478 /**
 479  * the init function of the mp3 audio format handler
 480  *
 481  * \param p pointer to the struct to initialize
 482  */
 483 void mp3_init(struct audio_format_handler *p)
 484 {
 485         af = p;
 486         af->get_file_info = mp3_get_file_info;
 487         af->close_audio_file = mp3_close_audio_file;
 488         af->get_header_info = NULL;
 489         /* eof_tv gets overwritten in mp3_get_file_info() */
 490         af->eof_tv.tv_sec = 0;
 491         af->eof_tv.tv_usec = 100 * 1000;
 492         af->suffixes = mp3_suffixes;
 493 }