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 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 #if 0 /* this code is a mess, clean it up before reenabling */
 135 #define FLAC_SIGNATURE_SIZE 4
 136 #define FLAC_STREAMINFO_SIZE 34
 137 #define FLAC_SEEKPOINT_SIZE 18
 138
 139 enum {
 140   FLAC_STREAMINFO = 0,
 141   FLAC_PADDING,
 142   FLAC_APPLICATION,
 143   FLAC_SEEKTABLE,
 144   FLAC_VORBIS_COMMENT,
 145   FLAC_CUESHEET
 146 } flac_preamble_t;
 147
 148 static void
 149 get_flac_metadata (demuxer_t* demuxer)
 150 {
 151   uint8_t preamble[4];
 152   unsigned int blk_len;
 153   stream_t *s = demuxer->stream;
 154
 155   /* file is qualified; skip over the signature bytes in the stream */
 156   stream_seek (s, 4);
 157
 158   /* loop through the metadata blocks; use a do-while construct since there
 159    * will always be 1 metadata block */
 160   do {
 161     int r;
 162
 163     r = stream_read (s, (char *) preamble, FLAC_SIGNATURE_SIZE);
 164     if (r != FLAC_SIGNATURE_SIZE)
 165       return;
 166
 167     blk_len = AV_RB24(preamble + 1);
 168
 169     switch (preamble[0] & 0x7F)
 170     {
 171     case FLAC_VORBIS_COMMENT:
 172     {
 173       /* For a description of the format please have a look at */
 174       /* http://www.xiph.org/vorbis/doc/v-comment.html */
 175
 176       uint32_t length, comment_list_len;
 177       char comments[blk_len];
 178       uint8_t *ptr = comments;
 179       char *comment;
 180       int cn;
 181       char c;
 182
 183       if (stream_read (s, comments, blk_len) == blk_len)
 184       {
 185         length = AV_RL32(ptr);
 186         ptr += 4 + length;
 187
 188         comment_list_len = AV_RL32(ptr);
 189         ptr += 4;
 190
 191         cn = 0;
 192         for (; cn < comment_list_len; cn++)
 193         {
 194           length = AV_RL32(ptr);
 195           ptr += 4;
 196
 197           comment = ptr;
 198           if (&comment[length] < comments || &comment[length] >= &comments[blk_len])
 199             return;
 200           c = comment[length];
 201           comment[length] = 0;
 202
 203           if (!strncasecmp ("TITLE=", comment, 6) && (length - 6 > 0))
 204             demux_info_add (demuxer, "Title", comment + 6);
 205           else if (!strncasecmp ("ARTIST=", comment, 7) && (length - 7 > 0))
 206             demux_info_add (demuxer, "Artist", comment + 7);
 207           else if (!strncasecmp ("ALBUM=", comment, 6) && (length - 6 > 0))
 208             demux_info_add (demuxer, "Album", comment + 6);
 209           else if (!strncasecmp ("DATE=", comment, 5) && (length - 5 > 0))
 210             demux_info_add (demuxer, "Year", comment + 5);
 211           else if (!strncasecmp ("GENRE=", comment, 6) && (length - 6 > 0))
 212             demux_info_add (demuxer, "Genre", comment + 6);
 213           else if (!strncasecmp ("Comment=", comment, 8) && (length - 8 > 0))
 214             demux_info_add (demuxer, "Comment", comment + 8);
 215           else if (!strncasecmp ("TRACKNUMBER=", comment, 12)
 216                    && (length - 12 > 0))
 217           {
 218             char buf[31];
 219             buf[30] = '\0';
 220             sprintf (buf, "%d", atoi (comment + 12));
 221             demux_info_add(demuxer, "Track", buf);
 222           }
 223           comment[length] = c;
 224
 225           ptr += length;
 226         }
 227       }
 228       break;
 229     }
 230
 231     case FLAC_STREAMINFO:
 232     case FLAC_PADDING:
 233     case FLAC_APPLICATION:
 234     case FLAC_SEEKTABLE:
 235     case FLAC_CUESHEET:
 236     default:
 237       /* 6-127 are presently reserved */
 238       stream_skip (s, blk_len);
 239       break;
 240     }
 241   } while ((preamble[0] & 0x80) == 0);
 242 }
 243 #endif
 244
 245 static int demux_audio_open(demuxer_t* demuxer) {
 246   stream_t *s;
 247   sh_audio_t* sh_audio;
 248   uint8_t hdr[HDR_SIZE];
 249   int frmt = 0, n = 0, step;
 250   off_t st_pos = 0, next_frame_pos = 0;
 251   // mp3_hdrs list is sorted first by next_frame_pos and then by frame_pos
 252   mp3_hdr_t *mp3_hdrs = NULL, *mp3_found = NULL;
 253   da_priv_t* priv;
 254
 255   s = demuxer->stream;
 256
 257   stream_read(s, hdr, HDR_SIZE);
 258   while(n < 30000 && !s->eof) {
 259     int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
 260     st_pos = stream_tell(s) - HDR_SIZE;
 261     step = 1;
 262
 263     if( hdr[0] == 'R' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == 'F' ) {
 264       stream_skip(s,4);
 265       if(s->eof)
 266         break;
 267       stream_read(s,hdr,4);
 268       if(s->eof)
 269         break;
 270       if(hdr[0] != 'W' || hdr[1] != 'A' || hdr[2] != 'V'  || hdr[3] != 'E' )
 271         stream_skip(s,-8);
 272       else
 273       // We found wav header. Now we can have 'fmt ' or a mp3 header
 274       // empty the buffer
 275         step = 4;
 276     } else if( hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3' && (hdr[3] >= 2)) {
 277       int len;
 278       stream_skip(s,2);
 279       stream_read(s,hdr,4);
 280       len = (hdr[0]<<21) | (hdr[1]<<14) | (hdr[2]<<7) | hdr[3];
 281       stream_skip(s,len);
 282       step = 4;
 283     } else if( hdr[0] == 'f' && hdr[1] == 'm' && hdr[2] == 't' && hdr[3] == ' ' ) {
 284       frmt = WAV;
 285       break;
 286     } else if((mp3_flen = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
 287                                 &mpa_spf, &mpa_layer, &mpa_br)) > 0) {
 288       mp3_found = add_mp3_hdr(&mp3_hdrs, st_pos, mp3_chans, mp3_freq,
 289                               mpa_spf, mpa_layer, mpa_br, mp3_flen);
 290       if (mp3_found) {
 291         frmt = MP3;
 292         break;
 293       }
 294     } else if( hdr[0] == 'f' && hdr[1] == 'L' && hdr[2] == 'a' && hdr[3] == 'C' ) {
 295       frmt = fLaC;
 296       if (!mp3_hdrs || mp3_hdrs->cons_hdrs < 3)
 297         break;
 298     }
 299     // Add here some other audio format detection
 300     if(step < HDR_SIZE)
 301       memmove(hdr,&hdr[step],HDR_SIZE-step);
 302     stream_read(s, &hdr[HDR_SIZE - step], step);
 303     n++;
 304   }
 305
 306   free_mp3_hdrs(&mp3_hdrs);
 307
 308   if(!frmt)
 309     return 0;
 310
 311   sh_audio = new_sh_audio(demuxer,0);
 312
 313   switch(frmt) {
 314   case MP3:
 315     sh_audio->format = (mp3_found->mpa_layer < 3 ? 0x50 : 0x55);
 316     demuxer->movi_start = mp3_found->frame_pos;
 317     next_frame_pos = mp3_found->next_frame_pos;
 318     sh_audio->audio.dwSampleSize= 0;
 319     sh_audio->audio.dwScale = mp3_found->mpa_spf;
 320     sh_audio->audio.dwRate = mp3_found->mp3_freq;
 321     sh_audio->wf = malloc(sizeof(WAVEFORMATEX));
 322     sh_audio->wf->wFormatTag = sh_audio->format;
 323     sh_audio->wf->nChannels = mp3_found->mp3_chans;
 324     sh_audio->wf->nSamplesPerSec = mp3_found->mp3_freq;
 325     sh_audio->wf->nAvgBytesPerSec = mp3_found->mpa_br * (1000 / 8);
 326     sh_audio->wf->nBlockAlign = mp3_found->mpa_spf;
 327     sh_audio->wf->wBitsPerSample = 16;
 328     sh_audio->wf->cbSize = 0;
 329     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 330     free(mp3_found);
 331     mp3_found = NULL;
 332     if(s->end_pos && (s->flags & STREAM_SEEK) == STREAM_SEEK) {
 333       char tag[4];
 334       stream_seek(s,s->end_pos-128);
 335       stream_read(s,tag,3);
 336       tag[3] = '\0';
 337       if(strcmp(tag,"TAG"))
 338         demuxer->movi_end = s->end_pos;
 339       else {
 340         char buf[31];
 341         uint8_t g;
 342         demuxer->movi_end = stream_tell(s)-3;
 343         stream_read(s,buf,30);
 344         buf[30] = '\0';
 345         demux_info_add(demuxer,"Title",buf);
 346         stream_read(s,buf,30);
 347         buf[30] = '\0';
 348         demux_info_add(demuxer,"Artist",buf);
 349         stream_read(s,buf,30);
 350         buf[30] = '\0';
 351         demux_info_add(demuxer,"Album",buf);
 352         stream_read(s,buf,4);
 353         buf[4] = '\0';
 354         demux_info_add(demuxer,"Year",buf);
 355         stream_read(s,buf,30);
 356         buf[30] = '\0';
 357         demux_info_add(demuxer,"Comment",buf);
 358         if(buf[28] == 0 && buf[29] != 0) {
 359           uint8_t trk = (uint8_t)buf[29];
 360           sprintf(buf,"%d",trk);
 361           demux_info_add(demuxer,"Track",buf);
 362         }
 363         g = stream_read_char(s);
 364         demux_info_add(demuxer,"Genre",genres[g]);
 365       }
 366     }
 367     break;
 368   case WAV: {
 369     unsigned int chunk_type;
 370     unsigned int chunk_size;
 371     WAVEFORMATEX* w;
 372     int l;
 373     l = stream_read_dword_le(s);
 374     if(l < 16) {
 375       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too short (%d)!!!\n",l);
 376       l = 16;
 377     }
 378     if(l > MAX_WAVHDR_LEN) {
 379       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too long (%d)!!!\n",l);
 380       l = 16;
 381     }
 382     sh_audio->wf = w = malloc(l > sizeof(WAVEFORMATEX) ? l : sizeof(WAVEFORMATEX));
 383     w->wFormatTag = sh_audio->format = stream_read_word_le(s);
 384     w->nChannels = sh_audio->channels = stream_read_word_le(s);
 385     w->nSamplesPerSec = sh_audio->samplerate = stream_read_dword_le(s);
 386     w->nAvgBytesPerSec = stream_read_dword_le(s);
 387     w->nBlockAlign = stream_read_word_le(s);
 388     w->wBitsPerSample = stream_read_word_le(s);
 389     sh_audio->samplesize = (w->wBitsPerSample + 7) / 8;
 390     w->cbSize = 0;
 391     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 392     l -= 16;
 393     if (l >= 2) {
 394       w->cbSize = stream_read_word_le(s);
 395       l -= 2;
 396       if (l < w->cbSize) {
 397         mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] truncated extradata (%d < %d)\n",
 398                l,w->cbSize);
 399         w->cbSize = l;
 400       }
 401       stream_read(s,(char*)((char*)(w)+sizeof(WAVEFORMATEX)),w->cbSize);
 402       l -= w->cbSize;
 403     }
 404
 405     if( mp_msg_test(MSGT_DEMUX,MSGL_V) ) print_wave_header(w, MSGL_V);
 406     if(l)
 407       stream_skip(s,l);
 408     do
 409     {
 410       chunk_type = stream_read_fourcc(demuxer->stream);
 411       chunk_size = stream_read_dword_le(demuxer->stream);
 412       if (chunk_type != mmioFOURCC('d', 'a', 't', 'a'))
 413         stream_skip(demuxer->stream, chunk_size);
 414     } while (!s->eof && chunk_type != mmioFOURCC('d', 'a', 't', 'a'));
 415     demuxer->movi_start = stream_tell(s);
 416     demuxer->movi_end = chunk_size ? demuxer->movi_start + chunk_size : s->end_pos;
 417 //    printf("wav: %X .. %X\n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 418     // Check if it contains dts audio
 419     if((w->wFormatTag == 0x01) && (w->nChannels == 2) && (w->nSamplesPerSec == 44100)) {
 420         unsigned char buf[16384]; // vlc uses 16384*4 (4 dts frames)
 421         unsigned int i;
 422         memset(buf, 0, sizeof(buf));
 423         stream_read(s, buf, sizeof(buf));
 424         for (i = 0; i < sizeof(buf) - 5; i += 2) {
 425             // DTS, 14 bit, LE
 426             if((buf[i] == 0xff) && (buf[i+1] == 0x1f) && (buf[i+2] == 0x00) &&
 427                (buf[i+3] == 0xe8) && ((buf[i+4] & 0xfe) == 0xf0) && (buf[i+5] == 0x07)) {
 428                 sh_audio->format = 0x2001;
 429                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, LE\n");
 430                 break;
 431             }
 432             // DTS, 14 bit, BE
 433             if((buf[i] == 0x1f) && (buf[i+1] == 0xff) && (buf[i+2] == 0xe8) &&
 434                (buf[i+3] == 0x00) && (buf[i+4] == 0x07) && ((buf[i+5] & 0xfe) == 0xf0)) {
 435                 sh_audio->format = 0x2001;
 436                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, BE\n");
 437                 break;
 438             }
 439             // DTS, 16 bit, BE
 440             if((buf[i] == 0x7f) && (buf[i+1] == 0xfe) && (buf[i+2] == 0x80) &&
 441                (buf[i+3] == 0x01)) {
 442                 sh_audio->format = 0x2001;
 443                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, BE\n");
 444                 break;
 445             }
 446             // DTS, 16 bit, LE
 447             if((buf[i] == 0xfe) && (buf[i+1] == 0x7f) && (buf[i+2] == 0x01) &&
 448                (buf[i+3] == 0x80)) {
 449                 sh_audio->format = 0x2001;
 450                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, LE\n");
 451                 break;
 452             }
 453         }
 454         if (sh_audio->format == 0x2001)
 455             mp_msg(MSGT_DEMUX,MSGL_DBG2,"[demux_audio] DTS sync offset = %u\n", i);
 456
 457     }
 458     stream_seek(s,demuxer->movi_start);
 459   } break;
 460   case fLaC:
 461             sh_audio->format = mmioFOURCC('f', 'L', 'a', 'C');
 462             demuxer->movi_start = stream_tell(s) - 4;
 463             demuxer->movi_end = s->end_pos;
 464             if (demuxer->movi_end > demuxer->movi_start) {
 465               // try to find out approx. bitrate
 466               int64_t size = demuxer->movi_end - demuxer->movi_start;
 467               int64_t num_samples = 0;
 468               int32_t srate = 0;
 469               stream_skip(s, 14);
 470               stream_read(s, (char *)&srate, 3);
 471               srate = be2me_32(srate) >> 12;
 472               stream_read(s, (char *)&num_samples, 5);
 473               num_samples = (be2me_64(num_samples) >> 24) & 0xfffffffffULL;
 474               if (num_samples && srate)
 475                 sh_audio->i_bps = size * srate / num_samples;
 476             }
 477             if (sh_audio->i_bps < 1) // guess value to prevent crash
 478               sh_audio->i_bps = 64 * 1024;
 479 //          get_flac_metadata (demuxer);
 480             break;
 481   }
 482
 483   priv = malloc(sizeof(da_priv_t));
 484   priv->frmt = frmt;
 485   priv->next_pts = 0;
 486   demuxer->priv = priv;
 487   demuxer->audio->id = 0;
 488   demuxer->audio->sh = sh_audio;
 489   sh_audio->ds = demuxer->audio;
 490   sh_audio->samplerate = sh_audio->audio.dwRate;
 491
 492   if(stream_tell(s) != demuxer->movi_start)
 493   {
 494     mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking from 0x%X to start pos 0x%X\n",
 495             (int)stream_tell(s), (int)demuxer->movi_start);
 496     stream_seek(s,demuxer->movi_start);
 497     if (stream_tell(s) != demuxer->movi_start) {
 498       mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking failed, now at 0x%X!\n",
 499               (int)stream_tell(s));
 500       if (next_frame_pos) {
 501         mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking to 0x%X instead\n",
 502                 (int)next_frame_pos);
 503         stream_seek(s, next_frame_pos);
 504       }
 505     }
 506   }
 507
 508   mp_msg(MSGT_DEMUX,MSGL_V,"demux_audio: audio data 0x%X - 0x%X  \n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 509
 510   return DEMUXER_TYPE_AUDIO;
 511 }
 512
 513
 514 static int demux_audio_fill_buffer(demuxer_t *demuxer, demux_stream_t *ds) {
 515   int l;
 516   demux_packet_t* dp;
 517   sh_audio_t* sh_audio = ds->sh;
 518   demuxer_t* demux = ds->demuxer;
 519   da_priv_t* priv = demux->priv;
 520   double this_pts = priv->next_pts;
 521   stream_t* s = demux->stream;
 522
 523   if(s->eof)
 524     return 0;
 525
 526   switch(priv->frmt) {
 527   case MP3 :
 528     while(1) {
 529       uint8_t hdr[4];
 530       stream_read(s,hdr,4);
 531       if (s->eof)
 532         return 0;
 533       l = mp_decode_mp3_header(hdr);
 534       if(l < 0) {
 535         if (demux->movi_end && stream_tell(s) >= demux->movi_end)
 536           return 0; // might be ID3 tag, i.e. EOF
 537         stream_skip(s,-3);
 538       } else {
 539         dp = new_demux_packet(l);
 540         memcpy(dp->buffer,hdr,4);
 541         if (stream_read(s,dp->buffer + 4,l-4) != l-4)
 542         {
 543           free_demux_packet(dp);
 544           return 0;
 545         }
 546         priv->next_pts += sh_audio->audio.dwScale/(double)sh_audio->samplerate;
 547         break;
 548       }
 549     } break;
 550   case WAV : {
 551     unsigned align = sh_audio->wf->nBlockAlign;
 552     l = sh_audio->wf->nAvgBytesPerSec;
 553     if (l <= 0) l = 65536;
 554     if (demux->movi_end && l > demux->movi_end - stream_tell(s)) {
 555       // do not read beyond end, there might be junk after data chunk
 556       l = demux->movi_end - stream_tell(s);
 557       if (l <= 0) return 0;
 558     }
 559     if (align)
 560       l = (l + align - 1) / align * align;
 561     dp = new_demux_packet(l);
 562     l = stream_read(s,dp->buffer,l);
 563     priv->next_pts += l/(double)sh_audio->i_bps;
 564     break;
 565   }
 566   case fLaC: {
 567     l = 65535;
 568     dp = new_demux_packet(l);
 569     l = stream_read(s,dp->buffer,l);
 570     /* FLAC is not a constant-bitrate codec. These values will be wrong. */
 571     priv->next_pts += l/(double)sh_audio->i_bps;
 572     break;
 573   }
 574   default:
 575     mp_msg(MSGT_DEMUXER,MSGL_WARN,MSGTR_MPDEMUX_AUDIO_UnknownFormat,priv->frmt);
 576     return 0;
 577   }
 578
 579   resize_demux_packet(dp, l);
 580   dp->pts = this_pts;
 581   ds_add_packet(ds, dp);
 582   return 1;
 583 }
 584
 585 static void high_res_mp3_seek(demuxer_t *demuxer,float time) {
 586   uint8_t hdr[4];
 587   int len,nf;
 588   da_priv_t* priv = demuxer->priv;
 589   sh_audio_t* sh = (sh_audio_t*)demuxer->audio->sh;
 590
 591   nf = time*sh->samplerate/sh->audio.dwScale;
 592   while(nf > 0) {
 593     stream_read(demuxer->stream,hdr,4);
 594     len = mp_decode_mp3_header(hdr);
 595     if(len < 0) {
 596       stream_skip(demuxer->stream,-3);
 597       continue;
 598     }
 599     stream_skip(demuxer->stream,len-4);
 600     priv->next_pts += sh->audio.dwScale/(double)sh->samplerate;
 601     nf--;
 602   }
 603 }
 604
 605 static void demux_audio_seek(demuxer_t *demuxer,float rel_seek_secs,float audio_delay,int flags){
 606   sh_audio_t* sh_audio;
 607   stream_t* s;
 608   int64_t base,pos;
 609   float len;
 610   da_priv_t* priv;
 611
 612   if(!(sh_audio = demuxer->audio->sh))
 613     return;
 614   s = demuxer->stream;
 615   priv = demuxer->priv;
 616
 617   if(priv->frmt == MP3 && hr_mp3_seek && !(flags & SEEK_FACTOR)) {
 618     len = (flags & SEEK_ABSOLUTE) ? rel_seek_secs - priv->next_pts : rel_seek_secs;
 619     if(len < 0) {
 620       stream_seek(s,demuxer->movi_start);
 621       len = priv->next_pts + len;
 622       priv->next_pts = 0;
 623     }
 624     if(len > 0)
 625       high_res_mp3_seek(demuxer,len);
 626     return;
 627   }
 628
 629   base = flags&SEEK_ABSOLUTE ? demuxer->movi_start : stream_tell(s);
 630   if(flags&SEEK_FACTOR)
 631     pos = base + ((demuxer->movi_end - demuxer->movi_start)*rel_seek_secs);
 632   else
 633     pos = base + (rel_seek_secs*sh_audio->i_bps);
 634
 635   if(demuxer->movi_end && pos >= demuxer->movi_end) {
 636      pos = demuxer->movi_end;
 637   } else if(pos < demuxer->movi_start)
 638     pos = demuxer->movi_start;
 639
 640   priv->next_pts = (pos-demuxer->movi_start)/(double)sh_audio->i_bps;
 641
 642   switch(priv->frmt) {
 643   case WAV:
 644     pos -= (pos - demuxer->movi_start) %
 645             (sh_audio->wf->nBlockAlign ? sh_audio->wf->nBlockAlign :
 646              (sh_audio->channels * sh_audio->samplesize));
 647     break;
 648   }
 649
 650   stream_seek(s,pos);
 651 }
 652
 653 static void demux_close_audio(demuxer_t* demuxer) {
 654   da_priv_t* priv = demuxer->priv;
 655
 656   if(!priv)
 657     return;
 658   free(priv);
 659 }
 660
 661 static int demux_audio_control(demuxer_t *demuxer,int cmd, void *arg){
 662     sh_audio_t *sh_audio=demuxer->audio->sh;
 663     int audio_length = sh_audio->i_bps ? demuxer->movi_end / sh_audio->i_bps : 0;
 664     da_priv_t* priv = demuxer->priv;
 665
 666     switch(cmd) {
 667         case DEMUXER_CTRL_GET_TIME_LENGTH:
 668             if (audio_length<=0) return DEMUXER_CTRL_DONTKNOW;
 669             *((double *)arg)=(double)audio_length;
 670             return DEMUXER_CTRL_GUESS;
 671
 672         case DEMUXER_CTRL_GET_PERCENT_POS:
 673             if (audio_length<=0)
 674                 return DEMUXER_CTRL_DONTKNOW;
 675             *((int *)arg)=(int)( (priv->next_pts*100)  / audio_length);
 676             return DEMUXER_CTRL_OK;
 677
 678         default:
 679             return DEMUXER_CTRL_NOTIMPL;
 680     }
 681 }
 682
 683
 684 const demuxer_desc_t demuxer_desc_audio = {
 685   "Audio demuxer",
 686   "audio",
 687   "Audio only",
 688   "?",
 689   "Audio only files",
 690   DEMUXER_TYPE_AUDIO,
 691   0, // unsafe autodetect
 692   demux_audio_open,
 693   demux_audio_fill_buffer,
 694   NULL,
 695   demux_close_audio,
 696   demux_audio_seek,
 697   demux_audio_control
 698 };