mp3_afh.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_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 "afs.h"
  34 #include "afh.h"
  35 #include "error.h"
  36 #include "fd.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 3
  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         char *filename;
  73         FILE *file;
  74         struct mp3header header;
  75         int id3_isvalid;
  76         struct id3tag id3;
  77         int vbr;
  78         long unsigned br_average;
  79         long unsigned seconds;
  80         int frames;
  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 struct mp3info mp3;
 109 static char mp3buf[8192];
 110 static int chunk_size;
 111 static struct audio_format_handler *af;
 112
 113 static int header_frequency(struct mp3header *h)
 114 {
 115         if (h->version > 2 || h->freq > 3)
 116                 return -E_HEADER_FREQ;
 117         return frequencies[h->version][h->freq];
 118 }
 119
 120 static const char *header_mode(struct mp3header *h)
 121 {
 122         if (h->mode > 4)
 123                 h->mode = 4; /* invalid */
 124         return mode_text[h->mode];
 125 }
 126 static int header_bitrate(struct mp3header *h)
 127 {
 128         if (h->layer > 3 || h->bitrate > 14)
 129                 return -E_HEADER_BITRATE;
 130         return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
 131 }
 132
 133 static int frame_length(struct mp3header *header)
 134 {
 135         int hb, hf = header_frequency(header);
 136
 137         if (hf < 0)
 138                 return hf;
 139         hb = header_bitrate(header);
 140         if (hb < 0)
 141                 return hb;
 142         if (header->sync != 0xFFE || header->layer > 3)
 143                 return -E_FRAME;
 144         return frame_size_index[3 - header->layer] *
 145                 ((header->version & 1) + 1) * hb / hf
 146                 + header->padding;
 147 }
 148
 149 static void write_info_str(char *info_str)
 150 {
 151         int v = mp3.id3_isvalid;
 152
 153         snprintf(info_str, MMD_INFO_SIZE,
 154                 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
 155                 "audio_file_info2:%s, by %s\n"
 156                 "audio_file_info3:A: %s, Y: %s, C: %s\n",
 157                 mp3.frames,
 158                 tv2ms(&af->chunk_tv),
 159                 mp3.br_average,
 160                 mp3.vbr? 'v' : 'c',
 161                 mp3.freq / 1000,
 162                 header_mode(&mp3.header),
 163                 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
 164                 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
 165                 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
 166                 v && *mp3.id3.year? mp3.id3.year : "????",
 167                 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
 168         );
 169 }
 170
 171 /*
 172  * Remove trailing whitespace from the end of a string
 173  */
 174 static char *unpad(char *string)
 175 {
 176         char *pos = string + strlen(string) - 1;
 177         while (isspace(pos[0]))
 178                 (pos--)[0] = 0;
 179         return string;
 180 }
 181
 182 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
 183 {
 184         if ((*(uint*)h1) == (*(uint*)h2))
 185                 return 1;
 186         if ((h1->version == h2->version) &&
 187                         (h1->layer == h2->layer) &&
 188                         (h1->crc == h2->crc) &&
 189                         (h1->freq == h2->freq) &&
 190                         (h1->mode == h2->mode) &&
 191                         (h1->copyright == h2->copyright) &&
 192                         (h1->original == h2->original) &&
 193                         (h1->emphasis == h2->emphasis))
 194                 return 1;
 195         else
 196                 return 0;
 197 }
 198
 199 /**
 200  * get next MP3 frame header.
 201  *
 202  * \param stream to read the header from
 203  * \param header structure that gets filled in by get_header()
 204  *
 205  * \return On success, the header frame length is returned.  A return value of
 206  * zero means that we did not retrieve a valid frame header, and a negative
 207  * return value indicates an error.
 208  */
 209 static int get_header(FILE *file, struct mp3header *header)
 210 {
 211         unsigned char buffer[FRAME_HEADER_SIZE];
 212         int fl, ret;
 213
 214         if (!file || !header)
 215                 return -E_MP3_NO_FILE;
 216         ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
 217         if (ret < FRAME_HEADER_SIZE) {
 218                 header->sync = 0;
 219                 return ret < 0? ret : 0;
 220         }
 221         header->layer = (buffer[1] >> 1) & 3;
 222         header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
 223         if (buffer[1] & 0x10)
 224                 header->version = (buffer[1] >> 3) & 1;
 225         else
 226                 header->version = 2;
 227         if ((header->sync != 0xFFE) || (header->layer != 1)) {
 228                 header->sync = 0;
 229 //              PARA_DEBUG_LOG("%s: header not found\n", __func__);
 230                 return 0;
 231         }
 232         header->crc = buffer[1] & 1;
 233         header->bitrate = (buffer[2] >> 4) & 0x0F;
 234 //      PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
 235 //              header->bitrate);
 236         header->freq = (buffer[2] >> 2) & 0x3;
 237         header->padding = (buffer[2] >>1) & 0x1;
 238         header->mode = (buffer[3] >> 6) & 0x3;
 239         fl = frame_length(header);
 240         return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
 241 }
 242
 243 /**
 244  * find the next mp3 header
 245  *
 246  * \return On success, the length of the next frame header. If the end of the
 247  * file was reached, the function returns zero. On errors, a negative value is
 248  * returned.
 249  *
 250  */
 251 static int mp3_seek_next_header(void)
 252 {
 253         int k, l = 0, c, first_len;
 254         struct mp3header h, h2;
 255         long valid_start = 0;
 256
 257         while (1) {
 258                 while ((c = fgetc(mp3.file)) != 255 && (c != EOF))
 259                         ; /* nothing */
 260                 if (c != 255)
 261                         return 0;
 262                 ungetc(c, mp3.file);
 263                 valid_start = ftell(mp3.file);
 264                 first_len = get_header(mp3.file, &h);
 265                 if (first_len <= 0)
 266                         continue;
 267                 if (fseek(mp3.file, first_len - FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 268                         return -E_FSEEK;
 269                 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
 270                         if ((l = get_header(mp3.file, &h2)) <= 0)
 271                                 break;
 272                         if (!compare_headers(&h, &h2))
 273                                 break;
 274                         fseek(mp3.file, l - FRAME_HEADER_SIZE, SEEK_CUR);
 275                 }
 276                 if (k == MIN_CONSEC_GOOD_FRAMES) {
 277                         fseek(mp3.file, valid_start, SEEK_SET);
 278                         memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
 279                         return first_len;
 280                 }
 281         }
 282 }
 283
 284 static int mp3_get_id3(void)
 285 {
 286         char fbuf[4];
 287
 288         mp3.id3_isvalid = 0;
 289         mp3.id3.title[0] = '\0';
 290         mp3.id3.artist[0] = '\0';
 291         mp3.id3.album[0] = '\0';
 292         mp3.id3.comment[0] = '\0';
 293         mp3.id3.year[0] = '\0';
 294         if (fseek(mp3.file, -128, SEEK_END))
 295                 return -E_FSEEK;
 296         if (para_fread(fbuf, 1, 3, mp3.file) < 0)
 297                 return -E_FREAD;
 298         fbuf[3] = '\0';
 299         if (strcmp("TAG", fbuf)) {
 300                 PARA_INFO_LOG("%s", "no id3 tag\n");
 301                 return 0;
 302         }
 303         if (fseek(mp3.file, -125, SEEK_END) < 0)
 304                 return -E_FSEEK;
 305         if (para_fread(mp3.id3.title, 1, 30, mp3.file) != 30)
 306                 return -E_FREAD;
 307         mp3.id3.title[30] = '\0';
 308         if (para_fread(mp3.id3.artist, 1, 30, mp3.file) != 30)
 309                 return -E_FREAD;
 310         mp3.id3.artist[30] = '\0';
 311         if (para_fread(mp3.id3.album, 1, 30, mp3.file) != 30)
 312                 return -E_FREAD;
 313         mp3.id3.album[30] = '\0';
 314         if (para_fread(mp3.id3.year, 1, 4, mp3.file) != 4)
 315                 return -E_FREAD;
 316         mp3.id3.year[4] = '\0';
 317         if (para_fread(mp3.id3.comment, 1, 30, mp3.file) != 30)
 318                 return -E_FREAD;
 319         mp3.id3.comment[30] = '\0';
 320         mp3.id3_isvalid = 1;
 321         unpad(mp3.id3.title);
 322         unpad(mp3.id3.artist);
 323         unpad(mp3.id3.album);
 324         unpad(mp3.id3.year);
 325         unpad(mp3.id3.comment);
 326         return 1;
 327 }
 328
 329 static int find_valid_start(void)
 330 {
 331         int frame_len;
 332
 333         if (!mp3.file)
 334                 return -E_MP3_NO_FILE;
 335         frame_len = get_header(mp3.file, &mp3.header);
 336         if (frame_len < 0)
 337                 return frame_len;
 338         if (!frame_len) {
 339                 frame_len = mp3_seek_next_header();
 340                 if (frame_len <= 0)
 341                         return frame_len;
 342         } else
 343                 if (fseek(mp3.file, -FRAME_HEADER_SIZE, SEEK_CUR) < 0)
 344                         return -E_FSEEK;
 345         if (frame_len <= 1) /* FRAME_HEADER_SIZE? */
 346                 return -E_FRAME_LENGTH;
 347         return frame_len;
 348 }
 349
 350 static int mp3_read_info(void)
 351 {
 352         long fl_avg = 0, freq_avg = 0, br_avg = 0, fcount = 0;
 353         int ret, len = 0, old_br = -1;
 354         struct timeval total_time = {0, 0};
 355
 356         ret = mp3_get_id3();
 357         if (ret < 0)
 358                 return ret;
 359         rewind(mp3.file);
 360         mp3.vbr = 0;
 361         mp3.freq = 0;
 362         while (1) {
 363                 int freq, br, fl;
 364                 struct timeval tmp, cct; /* current chunk time */
 365                 if (len > 0)
 366                         if (fseek(mp3.file, len, SEEK_CUR) < 0)
 367                                 return -E_FSEEK;
 368                 len = find_valid_start();
 369                 if (len <= 0)
 370                         break;
 371                 freq = header_frequency(&mp3.header);
 372                 br = header_bitrate(&mp3.header);
 373                 fl = frame_length(&mp3.header);
 374                 if (freq < 0 || br < 0 || fl < 0)
 375                         continue;
 376                 tmp.tv_sec = fl;
 377                 tmp.tv_usec = 0;
 378                 tv_divide(br * 125, &tmp, &cct);
 379                 tv_add(&cct, &total_time, &tmp);
 380                 total_time = tmp;
 381 //              PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
 382                 fcount++;
 383                 if (fcount == 1) {
 384                         freq_avg = freq;
 385                         br_avg = br;
 386                         old_br = br;
 387                         fl_avg = fl;
 388                         continue;
 389                 }
 390                 freq_avg += (freq - freq_avg) / (fcount + 1);
 391                 fl_avg += (fl - fl_avg) / (fcount + 1);
 392                 br_avg += (br - br_avg) / (fcount + 1);
 393                 if (old_br != br)
 394                         mp3.vbr = 1;
 395                 old_br = br;
 396         }
 397         if (!fcount || !freq_avg || !br_avg)
 398                 return -E_MP3_INFO;
 399         mp3.br_average = br_avg;
 400         mp3.freq = freq_avg;
 401         mp3.frames = fcount;
 402         mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
 403         tv_divide(fcount, &total_time, &af->chunk_tv);
 404         rewind(mp3.file);
 405         PARA_DEBUG_LOG("chunk_time: %lums\n", tv2ms(&af->chunk_tv));
 406         tv_scale(3, &af->chunk_tv, &af->eof_tv);
 407         PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&af->eof_tv));
 408         return 1;
 409 }
 410
 411 /*
 412  * Read mp3 information from audio file
 413  */
 414 static int mp3_get_file_info(FILE *audio_file, char *info_str,
 415         long unsigned *frames, int *seconds)
 416 {
 417         int ret;
 418
 419         if (!audio_file)
 420                 return -E_MP3_NO_FILE;
 421         mp3.file = audio_file;
 422         ret = mp3_read_info();
 423         if (ret < 0) {
 424                 mp3.file = NULL;
 425                 return ret;
 426         }
 427         write_info_str(info_str);
 428         *frames = mp3.frames;
 429         *seconds = mp3.seconds;
 430         if (*seconds < 2 || !*frames)
 431                 return -E_MP3_INFO;
 432         return 1;
 433 }
 434
 435 static int mp3_reposition_stream(long unsigned new_frame)
 436 {
 437         int count = 0, len;
 438
 439         PARA_DEBUG_LOG("jmp to frame %lu/%i\n", new_frame, mp3.frames);
 440         rewind(mp3.file);
 441         while (count < new_frame && (len = find_valid_start()) > 0) {
 442 //              PARA_DEBUG_LOG("%s: jmp to frame %d\n", __func__, count);
 443                 if (fseek(mp3.file, len, SEEK_CUR) < 0)
 444                         return -E_FSEEK;
 445                 count++;
 446         }
 447         if (count != new_frame) {
 448                 rewind(mp3.file);
 449                 return -E_MP3_REPOS;
 450         }
 451         return 1;
 452 }
 453
 454 static int mp3_read_next_chunk(void)
 455 {
 456         int len = find_valid_start();
 457
 458         if (len <= 0) {
 459                 if (len < 0)
 460                         PARA_ERROR_LOG("invalid frame len (%d)\n", len);
 461                 return len;
 462         }
 463         chunk_size = para_fread(mp3buf, len, 1, mp3.file);
 464         if (len != chunk_size)
 465                 PARA_DEBUG_LOG("short read (%d/%d)\n", chunk_size, len);
 466         return chunk_size;
 467 }
 468
 469 static char *mp3_read_chunk(__a_unused long unsigned chunk_num, ssize_t *len)
 470 {
 471         *len = mp3_read_next_chunk();
 472         if (*len <= 0)
 473                 return NULL;
 474         return mp3buf;
 475 }
 476
 477 static void mp3_close_audio_file(void)
 478 {
 479         if (!mp3.file)
 480                 return;
 481         fclose(mp3.file);
 482         mp3.file = NULL;
 483 }
 484
 485 static const char* mp3_suffixes[] = {"mp3", NULL};
 486 void mp3_init(struct audio_format_handler *p)
 487 {
 488         af = p;
 489         af->get_file_info = mp3_get_file_info;
 490         af->reposition_stream = mp3_reposition_stream;
 491         af->read_chunk = mp3_read_chunk;
 492         af->close_audio_file = mp3_close_audio_file;
 493         af->get_header_info = NULL;
 494         /* eof_tv gets overwritten in mp3_get_file_info() */
 495         af->eof_tv.tv_sec = 0;
 496         af->eof_tv.tv_usec = 100 * 1000;
 497         af->suffixes = mp3_suffixes;
 498 }