libmpdemux/demux_audio.c

   1
   2 #include "config.h"
   3 #include "mp_msg.h"
   4 #include "help_mp.h"
   5
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include "stream/stream.h"
   9 #include "demuxer.h"
  10 #include "stheader.h"
  11 #include "genres.h"
  12 #include "mp3_hdr.h"
  13 #include "libavutil/intreadwrite.h"
  14
  15 #include <string.h>
  16 #ifdef MP_DEBUG
  17 #include <assert.h>
  18 #endif
  19
  20 #define MP3 1
  21 #define WAV 2
  22 #define fLaC 3
  23
  24
  25 #define HDR_SIZE 4
  26
  27 typedef struct da_priv {
  28   int frmt;
  29   float last_pts;
  30 } da_priv_t;
  31
  32 //! rather arbitrary value for maximum length of wav-format headers
  33 #define MAX_WAVHDR_LEN (1 * 1024 * 1024)
  34
  35 //! how many valid frames in a row we need before accepting as valid MP3
  36 #define MIN_MP3_HDRS 12
  37
  38 //! Used to describe a potential (chain of) MP3 headers we found
  39 typedef struct mp3_hdr {
  40   off_t frame_pos; // start of first frame in this "chain" of headers
  41   off_t next_frame_pos; // here we expect the next header with same parameters
  42   int mp3_chans;
  43   int mp3_freq;
  44   int mpa_spf;
  45   int mpa_layer;
  46   int mpa_br;
  47   int cons_hdrs; // if this reaches MIN_MP3_HDRS we accept as MP3 file
  48   struct mp3_hdr *next;
  49 } mp3_hdr_t;
  50
  51 extern void print_wave_header(WAVEFORMATEX *h, int verbose_level);
  52
  53 int hr_mp3_seek = 0;
  54
  55 /**
  56  * \brief free a list of MP3 header descriptions
  57  * \param list pointer to the head-of-list pointer
  58  */
  59 static void free_mp3_hdrs(mp3_hdr_t **list) {
  60   mp3_hdr_t *tmp;
  61   while (*list) {
  62     tmp = (*list)->next;
  63     free(*list);
  64     *list = tmp;
  65   }
  66 }
  67
  68 /**
  69  * \brief add another potential MP3 header to our list
  70  * If it fits into an existing chain this one is expanded otherwise
  71  * a new one is created.
  72  * All entries that expected a MP3 header before the current position
  73  * are discarded.
  74  * The list is expected to be and will be kept sorted by next_frame_pos
  75  * and when those are equal by frame_pos.
  76  * \param list pointer to the head-of-list pointer
  77  * \param st_pos stream position where the described header starts
  78  * \param mp3_chans number of channels as specified by the header (*)
  79  * \param mp3_freq sampling frequency as specified by the header (*)
  80  * \param mpa_spf frame size as specified by the header
  81  * \param mpa_layer layer type ("version") as specified by the header (*)
  82  * \param mpa_br bitrate as specified by the header
  83  * \param mp3_flen length of the frame as specified by the header
  84  * \return If non-null the current file is accepted as MP3 and the
  85  * mp3_hdr struct describing the valid chain is returned. Must be
  86  * freed independent of the list.
  87  *
  88  * parameters marked by (*) must be the same for all headers in the same chain
  89  */
  90 static mp3_hdr_t *add_mp3_hdr(mp3_hdr_t **list, off_t st_pos,
  91                                int mp3_chans, int mp3_freq, int mpa_spf,
  92                                int mpa_layer, int mpa_br, int mp3_flen) {
  93   mp3_hdr_t *tmp;
  94   int in_list = 0;
  95   while (*list && (*list)->next_frame_pos <= st_pos) {
  96     if (((*list)->next_frame_pos < st_pos) || ((*list)->mp3_chans != mp3_chans)
  97          || ((*list)->mp3_freq != mp3_freq) || ((*list)->mpa_layer != mpa_layer) ) {
  98       // wasn't valid!
  99       tmp = (*list)->next;
 100       free(*list);
 101       *list = tmp;
 102     } else {
 103       (*list)->cons_hdrs++;
 104       (*list)->next_frame_pos = st_pos + mp3_flen;
 105       (*list)->mpa_spf = mpa_spf;
 106       (*list)->mpa_br = mpa_br;
 107       if ((*list)->cons_hdrs >= MIN_MP3_HDRS) {
 108         // copy the valid entry, so that the list can be easily freed
 109         tmp = malloc(sizeof(mp3_hdr_t));
 110         memcpy(tmp, *list, sizeof(mp3_hdr_t));
 111         tmp->next = NULL;
 112         return tmp;
 113       }
 114       in_list = 1;
 115       list = &((*list)->next);
 116     }
 117   }
 118   if (!in_list) { // does not belong into an existing chain, insert
 119     // find right position to insert to keep sorting
 120     while (*list && (*list)->next_frame_pos <= st_pos + mp3_flen)
 121       list = &((*list)->next);
 122     tmp = malloc(sizeof(mp3_hdr_t));
 123     tmp->frame_pos = st_pos;
 124     tmp->next_frame_pos = st_pos + mp3_flen;
 125     tmp->mp3_chans = mp3_chans;
 126     tmp->mp3_freq = mp3_freq;
 127     tmp->mpa_spf = mpa_spf;
 128     tmp->mpa_layer = mpa_layer;
 129     tmp->mpa_br = mpa_br;
 130     tmp->cons_hdrs = 1;
 131     tmp->next = *list;
 132     *list = tmp;
 133   }
 134   return NULL;
 135 }
 136
 137 #define FLAC_SIGNATURE_SIZE 4
 138 #define FLAC_STREAMINFO_SIZE 34
 139 #define FLAC_SEEKPOINT_SIZE 18
 140
 141 enum {
 142   FLAC_STREAMINFO = 0,
 143   FLAC_PADDING,
 144   FLAC_APPLICATION,
 145   FLAC_SEEKTABLE,
 146   FLAC_VORBIS_COMMENT,
 147   FLAC_CUESHEET
 148 } flac_preamble_t;
 149
 150 static void
 151 get_flac_metadata (demuxer_t* demuxer)
 152 {
 153   uint8_t preamble[4];
 154   unsigned int blk_len;
 155   stream_t *s = NULL;
 156
 157   if (!demuxer)
 158     return;
 159
 160   s = demuxer->stream;
 161   if (!s)
 162     return;
 163
 164   /* file is qualified; skip over the signature bytes in the stream */
 165   stream_seek (s, 4);
 166
 167   /* loop through the metadata blocks; use a do-while construct since there
 168    * will always be 1 metadata block */
 169   do {
 170     int r;
 171
 172     r = stream_read (s, (char *) preamble, FLAC_SIGNATURE_SIZE);
 173     if (r != FLAC_SIGNATURE_SIZE)
 174       return;
 175
 176     blk_len = (preamble[1] << 16) | (preamble[2] << 8) | (preamble[3] << 0);
 177
 178     switch (preamble[0] & 0x7F)
 179     {
 180     case FLAC_STREAMINFO:
 181     {
 182       if (blk_len != FLAC_STREAMINFO_SIZE)
 183         return;
 184
 185       stream_skip (s, FLAC_STREAMINFO_SIZE);
 186       break;
 187     }
 188
 189     case FLAC_PADDING:
 190       stream_skip (s, blk_len);
 191       break;
 192
 193     case FLAC_APPLICATION:
 194       stream_skip (s, blk_len);
 195       break;
 196
 197     case FLAC_SEEKTABLE:
 198     {
 199       int seekpoint_count, i;
 200
 201       seekpoint_count = blk_len / FLAC_SEEKPOINT_SIZE;
 202       for (i = 0; i < seekpoint_count; i++)
 203         if (stream_skip (s, FLAC_SEEKPOINT_SIZE) != 1)
 204           return;
 205       break;
 206     }
 207
 208     case FLAC_VORBIS_COMMENT:
 209     {
 210       /* For a description of the format please have a look at */
 211       /* http://www.xiph.org/vorbis/doc/v-comment.html */
 212
 213       uint32_t length, comment_list_len;
 214       char comments[blk_len];
 215       uint8_t *ptr = comments;
 216       char *comment;
 217       int cn;
 218       char c;
 219
 220       if (stream_read (s, comments, blk_len) == blk_len)
 221       {
 222         length = AV_RL32(ptr);
 223         ptr += 4 + length;
 224
 225         comment_list_len = AV_RL32(ptr);
 226         ptr += 4;
 227
 228         cn = 0;
 229         for (; cn < comment_list_len; cn++)
 230         {
 231           length = AV_RL32(ptr);
 232           ptr += 4;
 233
 234           comment = ptr;
 235           c = comment[length];
 236           comment[length] = 0;
 237
 238           if (!strncasecmp ("TITLE=", comment, 6) && (length - 6 > 0))
 239             demux_info_add (demuxer, "Title", comment + 6);
 240           else if (!strncasecmp ("ARTIST=", comment, 7) && (length - 7 > 0))
 241             demux_info_add (demuxer, "Artist", comment + 7);
 242           else if (!strncasecmp ("ALBUM=", comment, 6) && (length - 6 > 0))
 243             demux_info_add (demuxer, "Album", comment + 6);
 244           else if (!strncasecmp ("DATE=", comment, 5) && (length - 5 > 0))
 245             demux_info_add (demuxer, "Year", comment + 5);
 246           else if (!strncasecmp ("GENRE=", comment, 6) && (length - 6 > 0))
 247             demux_info_add (demuxer, "Genre", comment + 6);
 248           else if (!strncasecmp ("Comment=", comment, 8) && (length - 8 > 0))
 249             demux_info_add (demuxer, "Comment", comment + 8);
 250           else if (!strncasecmp ("TRACKNUMBER=", comment, 12)
 251                    && (length - 12 > 0))
 252           {
 253             char buf[31];
 254             buf[30] = '\0';
 255             sprintf (buf, "%d", atoi (comment + 12));
 256             demux_info_add(demuxer, "Track", buf);
 257           }
 258           comment[length] = c;
 259
 260           ptr += length;
 261         }
 262       }
 263       break;
 264     }
 265
 266     case FLAC_CUESHEET:
 267       stream_skip (s, blk_len);
 268       break;
 269
 270     default:
 271       /* 6-127 are presently reserved */
 272       stream_skip (s, blk_len);
 273       break;
 274     }
 275   } while ((preamble[0] & 0x80) == 0);
 276 }
 277
 278 static int demux_audio_open(demuxer_t* demuxer) {
 279   stream_t *s;
 280   sh_audio_t* sh_audio;
 281   uint8_t hdr[HDR_SIZE];
 282   int frmt = 0, n = 0, step;
 283   off_t st_pos = 0, next_frame_pos = 0;
 284   // mp3_hdrs list is sorted first by next_frame_pos and then by frame_pos
 285   mp3_hdr_t *mp3_hdrs = NULL, *mp3_found = NULL;
 286   da_priv_t* priv;
 287 #ifdef MP_DEBUG
 288   assert(demuxer != NULL);
 289   assert(demuxer->stream != NULL);
 290 #endif
 291
 292   s = demuxer->stream;
 293
 294   stream_read(s, hdr, HDR_SIZE);
 295   while(n < 30000 && !s->eof) {
 296     int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
 297     st_pos = stream_tell(s) - HDR_SIZE;
 298     step = 1;
 299
 300     if( hdr[0] == 'R' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == 'F' ) {
 301       stream_skip(s,4);
 302       if(s->eof)
 303         break;
 304       stream_read(s,hdr,4);
 305       if(s->eof)
 306         break;
 307       if(hdr[0] != 'W' || hdr[1] != 'A' || hdr[2] != 'V'  || hdr[3] != 'E' )
 308         stream_skip(s,-8);
 309       else
 310       // We found wav header. Now we can have 'fmt ' or a mp3 header
 311       // empty the buffer
 312         step = 4;
 313     } else if( hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3' && (hdr[3] >= 2)) {
 314       int len;
 315       stream_skip(s,2);
 316       stream_read(s,hdr,4);
 317       len = (hdr[0]<<21) | (hdr[1]<<14) | (hdr[2]<<7) | hdr[3];
 318       stream_skip(s,len);
 319       step = 4;
 320     } else if( hdr[0] == 'f' && hdr[1] == 'm' && hdr[2] == 't' && hdr[3] == ' ' ) {
 321       frmt = WAV;
 322       break;
 323     } else if((mp3_flen = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
 324                                 &mpa_spf, &mpa_layer, &mpa_br)) > 0) {
 325       mp3_found = add_mp3_hdr(&mp3_hdrs, st_pos, mp3_chans, mp3_freq,
 326                               mpa_spf, mpa_layer, mpa_br, mp3_flen);
 327       if (mp3_found) {
 328         frmt = MP3;
 329         break;
 330       }
 331     } else if( hdr[0] == 'f' && hdr[1] == 'L' && hdr[2] == 'a' && hdr[3] == 'C' ) {
 332       frmt = fLaC;
 333       break;
 334     }
 335     // Add here some other audio format detection
 336     if(step < HDR_SIZE)
 337       memmove(hdr,&hdr[step],HDR_SIZE-step);
 338     stream_read(s, &hdr[HDR_SIZE - step], step);
 339     n++;
 340   }
 341
 342   free_mp3_hdrs(&mp3_hdrs);
 343
 344   if(!frmt)
 345     return 0;
 346
 347   sh_audio = new_sh_audio(demuxer,0);
 348
 349   switch(frmt) {
 350   case MP3:
 351     sh_audio->format = (mp3_found->mpa_layer < 3 ? 0x50 : 0x55);
 352     demuxer->movi_start = mp3_found->frame_pos;
 353     next_frame_pos = mp3_found->next_frame_pos;
 354     sh_audio->audio.dwSampleSize= 0;
 355     sh_audio->audio.dwScale = mp3_found->mpa_spf;
 356     sh_audio->audio.dwRate = mp3_found->mp3_freq;
 357     sh_audio->wf = malloc(sizeof(WAVEFORMATEX));
 358     sh_audio->wf->wFormatTag = sh_audio->format;
 359     sh_audio->wf->nChannels = mp3_found->mp3_chans;
 360     sh_audio->wf->nSamplesPerSec = mp3_found->mp3_freq;
 361     sh_audio->wf->nAvgBytesPerSec = mp3_found->mpa_br * (1000 / 8);
 362     sh_audio->wf->nBlockAlign = mp3_found->mpa_spf;
 363     sh_audio->wf->wBitsPerSample = 16;
 364     sh_audio->wf->cbSize = 0;
 365     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 366     free(mp3_found);
 367     mp3_found = NULL;
 368     if(s->end_pos) {
 369       char tag[4];
 370       stream_seek(s,s->end_pos-128);
 371       stream_read(s,tag,3);
 372       tag[3] = '\0';
 373       if(strcmp(tag,"TAG"))
 374         demuxer->movi_end = s->end_pos;
 375       else {
 376         char buf[31];
 377         uint8_t g;
 378         demuxer->movi_end = stream_tell(s)-3;
 379         stream_read(s,buf,30);
 380         buf[30] = '\0';
 381         demux_info_add(demuxer,"Title",buf);
 382         stream_read(s,buf,30);
 383         buf[30] = '\0';
 384         demux_info_add(demuxer,"Artist",buf);
 385         stream_read(s,buf,30);
 386         buf[30] = '\0';
 387         demux_info_add(demuxer,"Album",buf);
 388         stream_read(s,buf,4);
 389         buf[4] = '\0';
 390         demux_info_add(demuxer,"Year",buf);
 391         stream_read(s,buf,30);
 392         buf[30] = '\0';
 393         demux_info_add(demuxer,"Comment",buf);
 394         if(buf[28] == 0 && buf[29] != 0) {
 395           uint8_t trk = (uint8_t)buf[29];
 396           sprintf(buf,"%d",trk);
 397           demux_info_add(demuxer,"Track",buf);
 398         }
 399         g = stream_read_char(s);
 400         demux_info_add(demuxer,"Genre",genres[g]);
 401       }
 402     }
 403     break;
 404   case WAV: {
 405     unsigned int chunk_type;
 406     unsigned int chunk_size;
 407     WAVEFORMATEX* w;
 408     int l;
 409     l = stream_read_dword_le(s);
 410     if(l < 16) {
 411       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too short (%d)!!!\n",l);
 412       l = 16;
 413     }
 414     if(l > MAX_WAVHDR_LEN) {
 415       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too long (%d)!!!\n",l);
 416       l = 16;
 417     }
 418     sh_audio->wf = w = malloc(l > sizeof(WAVEFORMATEX) ? l : sizeof(WAVEFORMATEX));
 419     w->wFormatTag = sh_audio->format = stream_read_word_le(s);
 420     w->nChannels = sh_audio->channels = stream_read_word_le(s);
 421     w->nSamplesPerSec = sh_audio->samplerate = stream_read_dword_le(s);
 422     w->nAvgBytesPerSec = stream_read_dword_le(s);
 423     w->nBlockAlign = stream_read_word_le(s);
 424     w->wBitsPerSample = stream_read_word_le(s);
 425     sh_audio->samplesize = (w->wBitsPerSample + 7) / 8;
 426     w->cbSize = 0;
 427     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 428     l -= 16;
 429     if (l > 0) {
 430     w->cbSize = stream_read_word_le(s);
 431     l -= 2;
 432      if (w->cbSize > 0) {
 433       if (l < w->cbSize) {
 434         mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] truncated extradata (%d < %d)\n",
 435         l,w->cbSize);
 436         stream_read(s,(char*)((char*)(w)+sizeof(WAVEFORMATEX)),l);
 437         l = 0;
 438       } else {
 439         stream_read(s,(char*)((char*)(w)+sizeof(WAVEFORMATEX)),w->cbSize);
 440         l -= w->cbSize;
 441       }
 442      }
 443     }
 444
 445     if( mp_msg_test(MSGT_DEMUX,MSGL_V) ) print_wave_header(w, MSGL_V);
 446     if(l)
 447       stream_skip(s,l);
 448     do
 449     {
 450       chunk_type = stream_read_fourcc(demuxer->stream);
 451       chunk_size = stream_read_dword_le(demuxer->stream);
 452       if (chunk_type != mmioFOURCC('d', 'a', 't', 'a'))
 453         stream_skip(demuxer->stream, chunk_size);
 454     } while (!s->eof && chunk_type != mmioFOURCC('d', 'a', 't', 'a'));
 455     demuxer->movi_start = stream_tell(s);
 456     demuxer->movi_end = chunk_size ? demuxer->movi_start + chunk_size : s->end_pos;
 457 //    printf("wav: %X .. %X\n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 458     // Check if it contains dts audio
 459     if((w->wFormatTag == 0x01) && (w->nChannels == 2) && (w->nSamplesPerSec == 44100)) {
 460         unsigned char buf[16384]; // vlc uses 16384*4 (4 dts frames)
 461         unsigned int i;
 462         stream_read(s, buf, sizeof(buf));
 463         for (i = 0; i < sizeof(buf) - 5; i += 2) {
 464             // DTS, 14 bit, LE
 465             if((buf[i] == 0xff) && (buf[i+1] == 0x1f) && (buf[i+2] == 0x00) &&
 466                (buf[i+3] == 0xe8) && ((buf[i+4] & 0xfe) == 0xf0) && (buf[i+5] == 0x07)) {
 467                 sh_audio->format = 0x2001;
 468                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, LE\n");
 469                 break;
 470             }
 471             // DTS, 14 bit, BE
 472             if((buf[i] == 0x1f) && (buf[i+1] == 0xff) && (buf[i+2] == 0xe8) &&
 473                (buf[i+3] == 0x00) && (buf[i+4] == 0x07) && ((buf[i+5] & 0xfe) == 0xf0)) {
 474                 sh_audio->format = 0x2001;
 475                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, BE\n");
 476                 break;
 477             }
 478             // DTS, 16 bit, BE
 479             if((buf[i] == 0x7f) && (buf[i+1] == 0xfe) && (buf[i+2] == 0x80) &&
 480                (buf[i+3] == 0x01)) {
 481                 sh_audio->format = 0x2001;
 482                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, BE\n");
 483                 break;
 484             }
 485             // DTS, 16 bit, LE
 486             if((buf[i] == 0xfe) && (buf[i+1] == 0x7f) && (buf[i+2] == 0x01) &&
 487                (buf[i+3] == 0x80)) {
 488                 sh_audio->format = 0x2001;
 489                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, LE\n");
 490                 break;
 491             }
 492         }
 493         if (sh_audio->format == 0x2001)
 494             mp_msg(MSGT_DEMUX,MSGL_DBG2,"[demux_audio] DTS sync offset = %u\n", i);
 495
 496     }
 497     stream_seek(s,demuxer->movi_start);
 498   } break;
 499   case fLaC:
 500             sh_audio->format = mmioFOURCC('f', 'L', 'a', 'C');
 501             demuxer->movi_start = stream_tell(s) - 4;
 502             demuxer->movi_end = s->end_pos;
 503             if (demuxer->movi_end > demuxer->movi_start) {
 504               // try to find out approx. bitrate
 505               int64_t size = demuxer->movi_end - demuxer->movi_start;
 506               int64_t num_samples = 0;
 507               int32_t srate = 0;
 508               stream_skip(s, 14);
 509               stream_read(s, (char *)&srate, 3);
 510               srate = be2me_32(srate) >> 12;
 511               stream_read(s, (char *)&num_samples, 5);
 512               num_samples = (be2me_64(num_samples) >> 24) & 0xfffffffffULL;
 513               if (num_samples && srate)
 514                 sh_audio->i_bps = size * srate / num_samples;
 515             }
 516             if (sh_audio->i_bps < 1) // guess value to prevent crash
 517               sh_audio->i_bps = 64 * 1024;
 518             get_flac_metadata (demuxer);
 519             break;
 520   }
 521
 522   priv = malloc(sizeof(da_priv_t));
 523   priv->frmt = frmt;
 524   priv->last_pts = -1;
 525   demuxer->priv = priv;
 526   demuxer->audio->id = 0;
 527   demuxer->audio->sh = sh_audio;
 528   sh_audio->ds = demuxer->audio;
 529   sh_audio->samplerate = sh_audio->audio.dwRate;
 530
 531   if(stream_tell(s) != demuxer->movi_start)
 532   {
 533     mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking from 0x%X to start pos 0x%X\n",
 534             (int)stream_tell(s), (int)demuxer->movi_start);
 535     stream_seek(s,demuxer->movi_start);
 536     if (stream_tell(s) != demuxer->movi_start) {
 537       mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking failed, now at 0x%X!\n",
 538               (int)stream_tell(s));
 539       if (next_frame_pos) {
 540         mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking to 0x%X instead\n",
 541                 (int)next_frame_pos);
 542         stream_seek(s, next_frame_pos);
 543       }
 544     }
 545   }
 546
 547   mp_msg(MSGT_DEMUX,MSGL_V,"demux_audio: audio data 0x%X - 0x%X  \n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 548
 549   return DEMUXER_TYPE_AUDIO;
 550 }
 551
 552
 553 static int demux_audio_fill_buffer(demuxer_t *demuxer, demux_stream_t *ds) {
 554   int l;
 555   demux_packet_t* dp;
 556   sh_audio_t* sh_audio;
 557   demuxer_t* demux;
 558   da_priv_t* priv;
 559   stream_t* s;
 560 #ifdef MP_DEBUG
 561   assert(ds != NULL);
 562   assert(ds->sh != NULL);
 563   assert(ds->demuxer != NULL);
 564 #endif
 565   sh_audio = ds->sh;
 566   demux = ds->demuxer;
 567   priv = demux->priv;
 568   s = demux->stream;
 569
 570   if(s->eof)
 571     return 0;
 572
 573   switch(priv->frmt) {
 574   case MP3 :
 575     while(1) {
 576       uint8_t hdr[4];
 577       stream_read(s,hdr,4);
 578       if (s->eof)
 579         return 0;
 580       l = mp_decode_mp3_header(hdr);
 581       if(l < 0) {
 582         if (demux->movi_end && stream_tell(s) >= demux->movi_end)
 583           return 0; // might be ID3 tag, i.e. EOF
 584         stream_skip(s,-3);
 585       } else {
 586         dp = new_demux_packet(l);
 587         memcpy(dp->buffer,hdr,4);
 588         if (stream_read(s,dp->buffer + 4,l-4) != l-4)
 589         {
 590           free_demux_packet(dp);
 591           return 0;
 592         }
 593         priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + sh_audio->audio.dwScale/(float)sh_audio->samplerate;
 594         break;
 595       }
 596     } break;
 597   case WAV : {
 598     unsigned align = sh_audio->wf->nBlockAlign;
 599     l = sh_audio->wf->nAvgBytesPerSec;
 600     if (demux->movi_end && l > demux->movi_end - stream_tell(s)) {
 601       // do not read beyond end, there might be junk after data chunk
 602       l = demux->movi_end - stream_tell(s);
 603       if (l <= 0) return 0;
 604     }
 605     if (align)
 606       l = (l + align - 1) / align * align;
 607     dp = new_demux_packet(l);
 608     l = stream_read(s,dp->buffer,l);
 609     priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + l/(float)sh_audio->i_bps;
 610     break;
 611   }
 612   case fLaC: {
 613     l = 65535;
 614     dp = new_demux_packet(l);
 615     l = stream_read(s,dp->buffer,l);
 616     priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + l/(float)sh_audio->i_bps;
 617     break;
 618   }
 619   default:
 620     mp_msg(MSGT_DEMUXER,MSGL_WARN,MSGTR_MPDEMUX_AUDIO_UnknownFormat,priv->frmt);
 621     return 0;
 622   }
 623
 624   resize_demux_packet(dp, l);
 625   dp->pts = priv->last_pts;
 626   ds_add_packet(ds, dp);
 627   return 1;
 628 }
 629
 630 static void high_res_mp3_seek(demuxer_t *demuxer,float time) {
 631   uint8_t hdr[4];
 632   int len,nf;
 633   da_priv_t* priv = demuxer->priv;
 634   sh_audio_t* sh = (sh_audio_t*)demuxer->audio->sh;
 635
 636   nf = time*sh->samplerate/sh->audio.dwScale;
 637   while(nf > 0) {
 638     stream_read(demuxer->stream,hdr,4);
 639     len = mp_decode_mp3_header(hdr);
 640     if(len < 0) {
 641       stream_skip(demuxer->stream,-3);
 642       continue;
 643     }
 644     stream_skip(demuxer->stream,len-4);
 645     priv->last_pts += sh->audio.dwScale/(float)sh->samplerate;
 646     nf--;
 647   }
 648 }
 649
 650 static void demux_audio_seek(demuxer_t *demuxer,float rel_seek_secs,float audio_delay,int flags){
 651   sh_audio_t* sh_audio;
 652   stream_t* s;
 653   int base,pos;
 654   float len;
 655   da_priv_t* priv;
 656
 657   if(!(sh_audio = demuxer->audio->sh))
 658     return;
 659   s = demuxer->stream;
 660   priv = demuxer->priv;
 661
 662   if(priv->frmt == MP3 && hr_mp3_seek && !(flags & 2)) {
 663     len = (flags & 1) ? rel_seek_secs - priv->last_pts : rel_seek_secs;
 664     if(len < 0) {
 665       stream_seek(s,demuxer->movi_start);
 666       len = priv->last_pts + len;
 667       priv->last_pts = 0;
 668     }
 669     if(len > 0)
 670       high_res_mp3_seek(demuxer,len);
 671     return;
 672   }
 673
 674   base = flags&1 ? demuxer->movi_start : stream_tell(s);
 675   if(flags&2)
 676     pos = base + ((demuxer->movi_end - demuxer->movi_start)*rel_seek_secs);
 677   else
 678     pos = base + (rel_seek_secs*sh_audio->i_bps);
 679
 680   if(demuxer->movi_end && pos >= demuxer->movi_end) {
 681      pos = demuxer->movi_end;
 682   } else if(pos < demuxer->movi_start)
 683     pos = demuxer->movi_start;
 684
 685   priv->last_pts = (pos-demuxer->movi_start)/(float)sh_audio->i_bps;
 686
 687   switch(priv->frmt) {
 688   case WAV:
 689     pos -= (pos - demuxer->movi_start) %
 690             (sh_audio->wf->nBlockAlign ? sh_audio->wf->nBlockAlign :
 691              (sh_audio->channels * sh_audio->samplesize));
 692     // We need to decrease the pts by one step to make it the "last one"
 693     priv->last_pts -= sh_audio->wf->nAvgBytesPerSec/(float)sh_audio->i_bps;
 694     break;
 695   }
 696
 697   stream_seek(s,pos);
 698 }
 699
 700 static void demux_close_audio(demuxer_t* demuxer) {
 701   da_priv_t* priv = demuxer->priv;
 702
 703   if(!priv)
 704     return;
 705   free(priv);
 706 }
 707
 708 static int demux_audio_control(demuxer_t *demuxer,int cmd, void *arg){
 709     sh_audio_t *sh_audio=demuxer->audio->sh;
 710     int audio_length = demuxer->movi_end / sh_audio->i_bps;
 711     da_priv_t* priv = demuxer->priv;
 712
 713     switch(cmd) {
 714         case DEMUXER_CTRL_GET_TIME_LENGTH:
 715             if (audio_length<=0) return DEMUXER_CTRL_DONTKNOW;
 716             *((double *)arg)=(double)audio_length;
 717             return DEMUXER_CTRL_GUESS;
 718
 719         case DEMUXER_CTRL_GET_PERCENT_POS:
 720             if (audio_length<=0)
 721                 return DEMUXER_CTRL_DONTKNOW;
 722             *((int *)arg)=(int)( (priv->last_pts*100)  / audio_length);
 723             return DEMUXER_CTRL_OK;
 724
 725         default:
 726             return DEMUXER_CTRL_NOTIMPL;
 727     }
 728 }
 729
 730
 731 demuxer_desc_t demuxer_desc_audio = {
 732   "Audio demuxer",
 733   "audio",
 734   "Audio file",
 735   "?",
 736   "Audio only files",
 737   DEMUXER_TYPE_AUDIO,
 738   0, // unsafe autodetect
 739   demux_audio_open,
 740   demux_audio_fill_buffer,
 741   NULL,
 742   demux_close_audio,
 743   demux_audio_seek,
 744   demux_audio_control
 745 };