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 "error.h"
  35 #include "fd.h"
  36 #include "string.h"
  37
  38 /** \cond some defines and structs which are only used in this file */
  39
  40 /*
  41  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  42  * to see before we decide we are looking at a real MP3 file
  43  */
  44 #define MIN_CONSEC_GOOD_FRAMES 4
  45
  46 #define FRAME_HEADER_SIZE 4
  47 #define MIN_FRAME_SIZE 21
  48
  49 struct mp3header {
  50         unsigned long sync;
  51         unsigned int version;
  52         unsigned int layer;
  53         unsigned int crc;
  54         unsigned int bitrate;
  55         unsigned int freq;
  56         unsigned int padding;
  57         unsigned int mode;
  58         unsigned int copyright;
  59         unsigned int original;
  60         unsigned int emphasis;
  61 };
  62
  63 struct id3tag {
  64         char title[31];
  65         char artist[31];
  66         char album[31];
  67         char year[5];
  68         char comment[31];
  69 };
  70
  71 struct mp3info {
  72         struct mp3header header;
  73         int id3_isvalid;
  74         struct id3tag id3;
  75         int vbr;
  76         long unsigned br_average;
  77         long unsigned seconds;
  78         int freq;
  79 };
  80
  81 /** \endcond */
  82 static const int frequencies[3][4] = {
  83         {22050,24000,16000,50000}, /* MPEG 2.0 */
  84         {44100,48000,32000,50000}, /* MPEG 1.0 */
  85         {11025,12000,8000,50000} /* MPEG 2.5 */
  86 };
  87
  88 static const int mp3info_bitrate[2][3][14] = {
  89 { /* MPEG 2.0 */
  90         {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
  91         {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
  92         {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
  93 },
  94
  95 { /* MPEG 1.0 */
  96         {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
  97         {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
  98         {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
  99 }
 100 };
 101
 102 static const int frame_size_index[] = {24000, 72000, 72000};
 103 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
 104
 105 static FILE *infile;
 106 static struct mp3info mp3;
 107 static struct audio_format_handler *af;
 108 static ssize_t num_chunks;
 109
 110 static int header_frequency(struct mp3header *h)
 111 {
 112         if (h->version > 2 || h->freq > 3)
 113                 return -E_HEADER_FREQ;
 114         return frequencies[h->version][h->freq];
 115 }
 116
 117 static const char *header_mode(struct mp3header *h)
 118 {
 119         if (h->mode > 4)
 120                 h->mode = 4; /* invalid */
 121         return mode_text[h->mode];
 122 }
 123 static int header_bitrate(struct mp3header *h)
 124 {
 125         if (h->layer > 3 || h->bitrate > 14)
 126                 return -E_HEADER_BITRATE;
 127         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 128 }
 129
 130 static int frame_length(struct mp3header *header)
 131 {
 132         int hb, hf = header_frequency(header);
 133
 134         if (hf < 0)
 135                 return hf;
 136         hb = header_bitrate(header);
 137         if (hb < 0)
 138                 return hb;
 139         if (header->sync != 0xFFE || header->layer > 3)
 140                 return -E_FRAME;
 141         return frame_size_index[3 - header->layer] *
 142                 ((header->version & 1) + 1) * hb / hf
 143                 + header->padding;
 144 }
 145
 146 static void write_info_str(struct audio_format_info *afi)
 147 {
 148         int v = mp3.id3_isvalid;
 149
 150         snprintf(afi->info_string, MMD_INFO_SIZE,
 151                 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
 152                 "audio_file_info2:%s, by %s\n"
 153                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 154                 num_chunks,
 155                 tv2ms(&afi->chunk_tv),
 156                 mp3.br_average,
 157                 mp3.vbr? 'v' : 'c',
 158                 mp3.freq / 1000,
 159                 header_mode(&mp3.header),
 160                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 161                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 162                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 163                 v && *mp3.id3.year? mp3.id3.year : "????",
 164                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 165         );
 166 }
 167
 168 /*
 169  * Remove trailing whitespace from the end of a string
 170  */
 171 static char *unpad(char *string)
 172 {
 173         char *pos = string + strlen(string) - 1;
 174         while (isspace(pos[0]))
 175                 (pos--)[0] = 0;
 176         return string;
 177 }
 178
 179 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 180 {
 181         if ((*(uint*)h1) == (*(uint*)h2))
 182                 return 1;
 183         if ((h1->version == h2->version) &&
 184                         (h1->layer == h2->layer) &&
 185                         (h1->crc == h2->crc) &&
 186                         (h1->freq == h2->freq) &&
 187                         (h1->mode == h2->mode) &&
 188                         (h1->copyright == h2->copyright) &&
 189                         (h1->original == h2->original) &&
 190                         (h1->emphasis == h2->emphasis))
 191                 return 1;
 192         return 0;
 193 }
 194
 195 /**
 196  * get next MP3 frame header.
 197  *
 198  * \param stream to read the header from
 199  * \param header structure that gets filled in by get_header()
 200  *
 201  * \return On success, the header frame length is returned.  A return value of
 202  * zero means that we did not retrieve a valid frame header, and a negative
 203  * return value indicates an error.
 204  */
 205 static int get_header(FILE *file, struct mp3header *header)
 206 {
 207         unsigned char buffer[FRAME_HEADER_SIZE];
 208         int fl, ret;
 209
 210         if (!file || !header)
 211                 return -E_MP3_NO_FILE;
 212         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 213         if (ret < FRAME_HEADER_SIZE) {
 214                 header->sync = 0;
 215                 return ret < 0? ret : 0;
 216         }
 217         header->layer = (buffer[1] >> 1) & 3;
 218         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 219         if (buffer[1] & 0x10)
 220                 header->version = (buffer[1] >> 3) & 1;
 221         else
 222                 header->version = 2;
 223         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 224                 header->sync = 0;
 225 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 226                 return 0;
 227         }
 228         header->crc = buffer[1] & 1;
 229         header->bitrate = (buffer[2] >> 4) & 0x0F;
 230 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 231 //              header->bitrate);
 232         header->freq = (buffer[2] >> 2) & 0x3;
 233         header->padding = (buffer[2] >>1) & 0x1;
 234         header->mode = (buffer[3] >> 6) & 0x3;
 235         fl = frame_length(header);
 236         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 237 }
 238
 239 /**
 240  * find the next mp3 header
 241  *
 242  * \return On success, the length of the next frame header. If the end of the
 243  * file was reached, the function returns zero. On errors, a negative value is
 244  * returned.
 245  *
 246  */
 247 static int mp3_seek_next_header(void)
 248 {
 249         int k, l = 0, c, first_len, ret;
 250         struct mp3header h, h2;
 251         long valid_start = 0;
 252
 253         while (1) {
 254                 while ((c = fgetc(infile)) != 255 && (c != EOF))
 255                         ; /* nothing */
 256                 if (c != 255)
 257                         return 0;
 258                 ungetc(c, infile);
 259                 valid_start = ftell(infile);
 260                 first_len = get_header(infile, &h);
 261                 if (first_len <= 0)
 262                         continue;
 263                 ret = para_fseek(infile, first_len - FRAME_HEADER_SIZE, SEEK_CUR);
 264                 if (ret < 0)
 265                         return ret;
 266                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 267                         if ((l = get_header(infile, &h2)) <= 0)
 268                                 break;
 269                         if (!compare_headers(&h, &h2))
 270                                 break;
 271                         ret = para_fseek(infile, l - FRAME_HEADER_SIZE, SEEK_CUR);
 272                         if (ret < 0)
 273                                 return ret;
 274                 }
 275                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 276                         ret = para_fseek(infile, valid_start, SEEK_SET);
 277                         if (ret < 0)
 278                                 return ret;
 279                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 280                         return first_len;
 281                 }
 282         }
 283 }
 284
 285 static int mp3_get_id3(void)
 286 {
 287         char fbuf[4];
 288         int ret;
 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         ret = para_fseek(infile, -128, SEEK_END);
 297         if (ret < 0 )
 298                 return ret;
 299         if (para_fread(fbuf, 1, 3, infile) < 0)
 300                 return -E_FREAD;
 301         fbuf[3] = '\0';
 302         if (strcmp("TAG", fbuf)) {
 303                 PARA_INFO_LOG("%s", "no id3 tag\n");
 304                 return 0;
 305         }
 306         ret = para_fseek(infile, -125, SEEK_END);
 307         if (ret < 0)
 308                 return ret;
 309         if (para_fread(mp3.id3.title, 1, 30, infile) != 30)
 310                 return -E_FREAD;
 311         mp3.id3.title[30] = '\0';
 312         if (para_fread(mp3.id3.artist, 1, 30, infile) != 30)
 313                 return -E_FREAD;
 314         mp3.id3.artist[30] = '\0';
 315         if (para_fread(mp3.id3.album, 1, 30, infile) != 30)
 316                 return -E_FREAD;
 317         mp3.id3.album[30] = '\0';
 318         if (para_fread(mp3.id3.year, 1, 4, infile) != 4)
 319                 return -E_FREAD;
 320         mp3.id3.year[4] = '\0';
 321         if (para_fread(mp3.id3.comment, 1, 30, infile) != 30)
 322                 return -E_FREAD;
 323         mp3.id3.comment[30] = '\0';
 324         mp3.id3_isvalid = 1;
 325         unpad(mp3.id3.title);
 326         unpad(mp3.id3.artist);
 327         unpad(mp3.id3.album);
 328         unpad(mp3.id3.year);
 329         unpad(mp3.id3.comment);
 330         return 1;
 331 }
 332
 333 static int find_valid_start(void)
 334 {
 335         int ret, frame_len;
 336
 337         if (!infile)
 338                 return -E_MP3_NO_FILE;
 339         frame_len = get_header(infile, &mp3.header);
 340         if (frame_len < 0)
 341                 return frame_len;
 342         if (!frame_len) {
 343                 frame_len = mp3_seek_next_header();
 344                 if (frame_len <= 0)
 345                         return frame_len;
 346         } else {
 347                 ret = para_fseek(infile, -FRAME_HEADER_SIZE, SEEK_CUR);
 348                 if (ret < 0)
 349                         return ret;
 350         }
 351         if (frame_len <= 1)
 352                 return -E_FRAME_LENGTH;
 353         return frame_len;
 354 }
 355
 356 static int mp3_read_info(struct audio_format_info *afi)
 357 {
 358         long fl_avg = 0, freq_avg = 0, br_avg = 0;
 359         int ret, len = 0, old_br = -1;
 360         struct timeval total_time = {0, 0};
 361         unsigned chunk_table_size = 1000; /* gets increased on demand */
 362
 363         num_chunks = 0;
 364         afi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
 365         ret = mp3_get_id3();
 366         if (ret < 0)
 367                 goto err_out;
 368         rewind(infile);
 369         mp3.vbr = 0;
 370         mp3.freq = 0;
 371         while (1) {
 372                 int freq, br, fl;
 373                 struct timeval tmp, cct; /* current chunk time */
 374                 if (len > 0) {
 375                         ret = para_fseek(infile, len, SEEK_CUR);
 376                         if (ret < 0)
 377                                 goto err_out;
 378                 }
 379                 len = find_valid_start();
 380                 if (len <= 0)
 381                         break;
 382                 freq = header_frequency(&mp3.header);
 383                 br = header_bitrate(&mp3.header);
 384                 fl = frame_length(&mp3.header);
 385                 if (freq < 0 || br < 0 || fl < 0)
 386                         continue;
 387                 tmp.tv_sec = fl;
 388                 tmp.tv_usec = 0;
 389                 tv_divide(br * 125, &tmp, &cct);
 390                 tv_add(&cct, &total_time, &tmp);
 391                 total_time = tmp;
 392                 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 393                 if (num_chunks >= chunk_table_size) {
 394                         chunk_table_size *= 2;
 395                         afi->chunk_table = para_realloc(afi->chunk_table,
 396                                 chunk_table_size * sizeof(size_t));
 397                 }
 398                 afi->chunk_table[num_chunks] = ftell(infile);
 399                 if (num_chunks < 10 || !(num_chunks % 1000))
 400                         PARA_INFO_LOG("chunk #%d: %zd\n", num_chunks,
 401                                 afi->chunk_table[num_chunks]);
 402                 num_chunks++;
 403                 if (num_chunks == 1) {
 404 //                      entry = ftell(infile);
 405 //                      PARA_INFO_LOG("entry: %zd\n", entry);
 406                         freq_avg = freq;
 407                         br_avg = br;
 408                         old_br = br;
 409                         fl_avg = fl;
 410                         continue;
 411                 }
 412                 freq_avg += (freq - freq_avg) / (num_chunks + 1);
 413                 fl_avg += (fl - fl_avg) / (num_chunks + 1);
 414                 br_avg += (br - br_avg) / (num_chunks + 1);
 415                 if (old_br != br)
 416                         mp3.vbr = 1;
 417                 old_br = br;
 418         }
 419         ret = -E_MP3_INFO;
 420         if (!num_chunks || !freq_avg || !br_avg)
 421                 goto err_out;
 422         ret= para_fseek(infile, 0, SEEK_END);
 423         if (ret < 0)
 424                 goto err_out;
 425         afi->chunk_table[num_chunks] = ftell(infile);
 426         mp3.br_average = br_avg;
 427         mp3.freq = freq_avg;
 428         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 429         tv_divide(num_chunks, &total_time, &afi->chunk_tv);
 430         rewind(infile);
 431         PARA_DEBUG_LOG("%zu chunks, each %lums\n", num_chunks, tv2ms(&afi->chunk_tv));
 432         tv_scale(3, &afi->chunk_tv, &afi->eof_tv);
 433         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afi->eof_tv));
 434         return 1;
 435 err_out:
 436         PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 437         free(afi->chunk_table);
 438         return ret;
 439 }
 440
 441 /*
 442  * Read mp3 information from audio file
 443  */
 444 static int mp3_get_file_info(FILE *audio_file, struct audio_format_info *afi)
 445 {
 446         int ret;
 447
 448         if (!audio_file)
 449                 return -E_MP3_NO_FILE;
 450         infile = audio_file;
 451         ret = mp3_read_info(afi);
 452         if (ret < 0) {
 453                 infile = NULL;
 454                 return ret;
 455         }
 456         write_info_str(afi);
 457         afi->chunks_total = num_chunks;
 458         afi->seconds_total = mp3.seconds;
 459         if (afi->seconds_total < 2 || !afi->chunks_total)
 460                 return -E_MP3_INFO;
 461         return 1;
 462 }
 463
 464 static void mp3_close_audio_file(void)
 465 {
 466         if (!infile)
 467                 return;
 468         fclose(infile);
 469         infile = NULL;
 470 }
 471
 472 static const char* mp3_suffixes[] = {"mp3", NULL};
 473
 474 /**
 475  * the init function of the mp3 audio format handler
 476  *
 477  * \param p pointer to the struct to initialize
 478  */
 479 void mp3_init(struct audio_format_handler *p)
 480 {
 481         af = p;
 482         af->get_file_info = mp3_get_file_info;
 483         af->close_audio_file = mp3_close_audio_file;
 484         af->suffixes = mp3_suffixes;
 485 }