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