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
  36 /** \cond some defines and structs which are only used in this file */
  37
  38 /*
  39  * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
  40  * to see before we decide we are looking at a real MP3 file
  41  */
  42 #define MIN_CONSEC_GOOD_FRAMES 3
  43
  44 #define FRAME_HEADER_SIZE 4
  45 #define MIN_FRAME_SIZE 21
  46
  47 struct mp3header {
  48         unsigned long sync;
  49         unsigned int version;
  50         unsigned int layer;
  51         unsigned int crc;
  52         unsigned int bitrate;
  53         unsigned int freq;
  54         unsigned int padding;
  55         unsigned int mode;
  56         unsigned int copyright;
  57         unsigned int original;
  58         unsigned int emphasis;
  59 };
  60
  61 struct id3tag {
  62         char title[31];
  63         char artist[31];
  64         char album[31];
  65         char year[5];
  66         char comment[31];
  67 };
  68
  69 struct mp3info {
  70         char *filename;
  71         FILE *file;
  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 frames;
  79         int freq;
  80 };
  81
  82 /** \endcond */
  83 static 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 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 int frame_size_index[] = {24000, 72000, 72000};
 104 static char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
 105
 106 static struct mp3info mp3;
 107 static char mp3buf[8192];
 108 static int chunk_size;
 109 static struct audio_format *af;
 110
 111 static __must_check int para_fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
 112 {
 113         size_t res = fread(ptr, size, nmemb, stream);
 114         if (res == nmemb)
 115                 return size * nmemb;
 116         if (feof(stream))
 117                 return 0;
 118         return -E_FREAD;
 119 }
 120
 121 static int header_frequency(struct mp3header *h)
 122 {
 123         if (h->version > 2 || h->freq > 3)
 124                 return -E_HEADER_FREQ;
 125         return frequencies[h->version][h->freq];
 126 }
 127
 128 static char *header_mode(struct mp3header *h)
 129 {
 130         if (h->mode > 4)
 131                 h->mode = 4; /* invalid */
 132         return mode_text[h->mode];
 133 }
 134 static int header_bitrate(struct mp3header *h)
 135 {
 136         if (h->layer > 3 || h->bitrate > 14)
 137                 return -E_HEADER_BITRATE;
 138         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 139 }
 140
 141 static int frame_length(struct mp3header *header)
 142 {
 143         int hb, hf = header_frequency(header);
 144
 145         if (hf < 0)
 146                 return hf;
 147         hb = header_bitrate(header);
 148         if (hb < 0)
 149                 return hb;
 150         if (header->sync != 0xFFE || header->layer > 3)
 151                 return -E_FRAME;
 152         return frame_size_index[3 - header->layer] *
 153                 ((header->version & 1) + 1) * hb / hf
 154                 + header->padding;
 155 }
 156
 157 static void write_info_str(char *info_str)
 158 {
 159         int v = mp3.id3_isvalid;
 160
 161         snprintf(info_str, MMD_INFO_SIZE,
 162                 "audio_file_info1:%d x %lu, %lu kbit/s (%cbr) %i KHz %s\n"
 163                 "audio_file_info2:%s, by %s\n"
 164                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 165                 mp3.frames,
 166                 af->chunk_tv.tv_usec,
 167                 mp3.br_average,
 168                 mp3.vbr? 'v' : 'c',
 169                 mp3.freq / 1000,
 170                 header_mode(&mp3.header),
 171                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 172                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 173                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 174                 v && *mp3.id3.year? mp3.id3.year : "????",
 175                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 176         );
 177 }
 178
 179 /*
 180  * Remove trailing whitespace from the end of a string
 181  */
 182 static char *unpad(char *string)
 183 {
 184         char *pos = string + strlen(string) - 1;
 185         while (isspace(pos[0]))
 186                 (pos--)[0] = 0;
 187         return string;
 188 }
 189
 190 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 191 {
 192         if ((*(uint*)h1) == (*(uint*)h2))
 193                 return 1;
 194         if ((h1->version == h2->version) &&
 195                         (h1->layer == h2->layer) &&
 196                         (h1->crc == h2->crc) &&
 197                         (h1->freq == h2->freq) &&
 198                         (h1->mode == h2->mode) &&
 199                         (h1->copyright == h2->copyright) &&
 200                         (h1->original == h2->original) &&
 201                         (h1->emphasis == h2->emphasis))
 202                 return 1;
 203         else
 204                 return 0;
 205 }
 206
 207 /**
 208  * get next MP3 frame header.
 209  *
 210  * \param stream to read the header from
 211  * \param header structure that gets filled in by get_header()
 212  *
 213  * \return On success, the header frame length is returned.  A return value of
 214  * zero means that we did not retrieve a valid frame header, and a negative
 215  * return value indicates an error.
 216  */
 217 static int get_header(FILE *file, struct mp3header *header)
 218 {
 219         unsigned char buffer[FRAME_HEADER_SIZE];
 220         int fl, ret;
 221
 222         if (!file || !header)
 223                 return -E_MP3_NO_FILE;
 224         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 225         if (ret < FRAME_HEADER_SIZE) {
 226                 header->sync = 0;
 227                 return ret < 0? ret : 0;
 228         }
 229         header->layer = (buffer[1] >> 1) & 3;
 230         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 231         if (buffer[1] & 0x10)
 232                 header->version = (buffer[1] >> 3) & 1;
 233         else
 234                 header->version = 2;
 235         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 236                 header->sync = 0;
 237 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 238                 return 0;
 239         }
 240         header->crc = buffer[1] & 1;
 241         header->bitrate = (buffer[2] >> 4) & 0x0F;
 242 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 243 //              header->bitrate);
 244         header->freq = (buffer[2] >> 2) & 0x3;
 245         header->padding = (buffer[2] >>1) & 0x1;
 246         header->mode = (buffer[3] >> 6) & 0x3;
 247         fl = frame_length(header);
 248         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 249 }
 250
 251 /**
 252  * find the next mp3 header
 253  *
 254  * \return On success, the length of the next frame header. If the end of the
 255  * file was reached, the function returns zero. On errors, a negative value is
 256  * returned.
 257  *
 258  */
 259 static int mp3_seek_next_header(void)
 260 {
 261         int k, l = 0, c, first_len;
 262         struct mp3header h, h2;
 263         long valid_start = 0;
 264
 265         while (1) {
 266                 while ((c = fgetc(mp3.file)) != 255 && (c != EOF))
 267                         ; /* nothing */
 268                 if (c != 255)
 269                         return 0;
 270                 ungetc(c, mp3.file);
 271                 valid_start = ftell(mp3.file);
 272                 first_len = get_header(mp3.file, &h);
 273                 if (first_len <= 0)
 274                         continue;
 275                 if (fseek(mp3.file, first_len - FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 276                         return -E_FSEEK;
 277                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 278                         if ((l = get_header(mp3.file, &h2)) <= 0)
 279                                 break;
 280                         if (!compare_headers(&h, &h2))
 281                                 break;
 282                         fseek(mp3.file, l - FRAME_HEADER_SIZE, SEEK_CUR);
 283                 }
 284                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 285                         fseek(mp3.file, valid_start, SEEK_SET);
 286                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 287                         return first_len;
 288                 }
 289         }
 290 }
 291
 292 static int mp3_get_id3(void)
 293 {
 294         char fbuf[4];
 295
 296         mp3.id3_isvalid = 0;
 297         mp3.id3.title[0] = '\0';
 298         mp3.id3.artist[0] = '\0';
 299         mp3.id3.album[0] = '\0';
 300         mp3.id3.comment[0] = '\0';
 301         mp3.id3.year[0] = '\0';
 302         if (fseek(mp3.file, -128, SEEK_END))
 303                 return -E_FSEEK;
 304         if (para_fread(fbuf, 1, 3, mp3.file) < 0)
 305                 return -E_FREAD;
 306         fbuf[3] = '\0';
 307         if (strcmp("TAG", fbuf)) {
 308                 PARA_INFO_LOG("%s", "no id3 tag\n");
 309                 return 0;
 310         }
 311         if (fseek(mp3.file, -125, SEEK_END) < 0)
 312                 return -E_FSEEK;
 313         if (para_fread(mp3.id3.title, 1, 30, mp3.file) != 30)
 314                 return -E_FREAD;
 315         mp3.id3.title[30] = '\0';
 316         if (para_fread(mp3.id3.artist, 1, 30, mp3.file) != 30)
 317                 return -E_FREAD;
 318         mp3.id3.artist[30] = '\0';
 319         if (para_fread(mp3.id3.album, 1, 30, mp3.file) != 30)
 320                 return -E_FREAD;
 321         mp3.id3.album[30] = '\0';
 322         if (para_fread(mp3.id3.year, 1, 4, mp3.file) != 4)
 323                 return -E_FREAD;
 324         mp3.id3.year[4] = '\0';
 325         if (para_fread(mp3.id3.comment, 1, 30, mp3.file) != 30)
 326                 return -E_FREAD;
 327         mp3.id3.comment[30] = '\0';
 328         mp3.id3_isvalid = 1;
 329         unpad(mp3.id3.title);
 330         unpad(mp3.id3.artist);
 331         unpad(mp3.id3.album);
 332         unpad(mp3.id3.year);
 333         unpad(mp3.id3.comment);
 334         return 1;
 335 }
 336
 337 static int find_valid_start(void)
 338 {
 339         int frame_len;
 340
 341         if (!mp3.file)
 342                 return -E_MP3_NO_FILE;
 343         frame_len = get_header(mp3.file, &mp3.header);
 344         if (frame_len < 0)
 345                 return frame_len;
 346         if (!frame_len) {
 347                 frame_len = mp3_seek_next_header();
 348                 if (frame_len <= 0)
 349                         return frame_len;
 350         } else
 351                 if (fseek(mp3.file, -FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 352                         return -E_FSEEK;
 353         if (frame_len <= 1) /* FRAME_HEADER_SIZE? */
 354                 return -E_FRAME_LENGTH;
 355         return frame_len;
 356 }
 357
 358 static int mp3_read_info(void)
 359 {
 360         long fl_avg = 0, freq_avg = 0, br_avg = 0, fcount = 0;
 361         int ret, len = 0, old_br = -1;
 362         struct timeval total_time = {0, 0};
 363
 364         ret = mp3_get_id3();
 365         if (ret < 0)
 366                 return ret;
 367         rewind(mp3.file);
 368         mp3.vbr = 0;
 369         mp3.freq = 0;
 370         while (1) {
 371                 int freq, br, fl;
 372                 struct timeval tmp, cct; /* current chunk time */
 373                 if (len > 0)
 374                         if (fseek(mp3.file, len, SEEK_CUR) < 0)
 375                                 return -E_FSEEK;
 376                 len = find_valid_start();
 377                 if (len <= 0)
 378                         break;
 379                 freq = header_frequency(&mp3.header);
 380                 br = header_bitrate(&mp3.header);
 381                 fl = frame_length(&mp3.header);
 382                 if (freq < 0 || br < 0 || fl < 0)
 383                         continue;
 384                 tmp.tv_sec = fl;
 385                 tmp.tv_usec = 0;
 386                 tv_divide(br * 125, &tmp, &cct);
 387                 tv_add(&cct, &total_time, &tmp);
 388                 total_time = tmp;
 389 //              PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 390                 fcount++;
 391                 if (fcount == 1) {
 392                         freq_avg = freq;
 393                         br_avg = br;
 394                         old_br = br;
 395                         fl_avg = fl;
 396                         continue;
 397                 }
 398                 freq_avg += (freq - freq_avg) / (fcount + 1);
 399                 fl_avg += (fl - fl_avg) / (fcount + 1);
 400                 br_avg += (br - br_avg) / (fcount + 1);
 401                 if (old_br != br)
 402                         mp3.vbr = 1;
 403                 old_br = br;
 404         }
 405         if (!fcount || !freq_avg || !br_avg)
 406                 return -E_MP3_INFO;
 407         mp3.br_average = br_avg;
 408         mp3.freq = freq_avg;
 409         mp3.frames = fcount;
 410         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 411         tv_divide(fcount, &total_time, &af->chunk_tv);
 412         rewind(mp3.file);
 413         PARA_DEBUG_LOG("chunk_time: %lu\n", af->chunk_tv.tv_usec);
 414         tv_scale(10, &af->chunk_tv, &af->eof_tv);
 415         return 1;
 416 }
 417
 418 /*
 419  * Read mp3 information from audio file
 420  */
 421 static int mp3_get_file_info(FILE *audio_file, char *info_str,
 422         long unsigned *frames, int *seconds)
 423 {
 424         int ret;
 425
 426         if (!audio_file)
 427                 return -E_MP3_NO_FILE;
 428         mp3.file = audio_file;
 429         ret = mp3_read_info();
 430         if (ret < 0) {
 431                 mp3.file = NULL;
 432                 return ret;
 433         }
 434         write_info_str(info_str);
 435         *frames = mp3.frames;
 436         *seconds = mp3.seconds;
 437         if (*seconds < 2 || !*frames)
 438                 return -E_MP3_INFO;
 439         return 1;
 440 }
 441
 442 static int mp3_reposition_stream(long unsigned new_frame)
 443 {
 444         int count = 0, len;
 445
 446         PARA_DEBUG_LOG("jmp to frame %lu/%i\n", new_frame, mp3.frames);
 447         rewind(mp3.file);
 448         while (count < new_frame && (len = find_valid_start()) > 0) {
 449 //              PARA_DEBUG_LOG("%s: jmp to frame %d\n", __func__, count);
 450                 if (fseek(mp3.file, len, SEEK_CUR) < 0)
 451                         return -E_FSEEK;
 452                 count++;
 453         }
 454         if (count != new_frame) {
 455                 rewind(mp3.file);
 456                 return -E_MP3_REPOS;
 457         }
 458         return 1;
 459 }
 460
 461 static int mp3_read_next_chunk(void)
 462 {
 463         int len = find_valid_start();
 464
 465         if (len <= 0) {
 466                 if (len < 0)
 467                         PARA_ERROR_LOG("invalid frame len (%d)\n", len);
 468                 return len;
 469         }
 470         chunk_size = para_fread(mp3buf, len, 1, mp3.file);
 471         if (len != chunk_size)
 472                 PARA_DEBUG_LOG("short read (%d/%d)\n", chunk_size, len);
 473         return chunk_size;
 474 }
 475
 476 static char *mp3_read_chunk(__unused long unsigned chunk_num, ssize_t *len)
 477 {
 478         *len = mp3_read_next_chunk();
 479         if (*len <= 0)
 480                 return NULL;
 481         return mp3buf;
 482 }
 483
 484 static void mp3_close_audio_file(void)
 485 {
 486         if (!mp3.file)
 487                 return;
 488         fclose(mp3.file);
 489         mp3.file = NULL;
 490 }
 491
 492 void mp3_init(void *p)
 493 {
 494         af = p;
 495         af->get_file_info = mp3_get_file_info;
 496         af->reposition_stream = mp3_reposition_stream;
 497         af->read_chunk = mp3_read_chunk;
 498         af->close_audio_file = mp3_close_audio_file;
 499         af->get_header_info = NULL;
 500         /* eof_tv gets overwritten in mp3_get_file_info() */
 501         af->eof_tv.tv_sec = 0;
 502         af->eof_tv.tv_usec = 100 * 1000;
 503 }