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