libmpdemux/demux_audio.c

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer 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  * MPlayer 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 along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23 #include <libavutil/intreadwrite.h>
  24
  25 #include "config.h"
  26 #include "options.h"
  27 #include "mp_msg.h"
  28
  29 #include "stream/stream.h"
  30 #include "aviprint.h"
  31 #include "demuxer.h"
  32 #include "stheader.h"
  33 #include "genres.h"
  34 #include "mp3_hdr.h"
  35
  36 #define MP3 1
  37 #define WAV 2
  38 #define fLaC 3
  39
  40
  41 #define HDR_SIZE 4
  42
  43 typedef struct da_priv {
  44   int frmt;
  45   double next_pts;
  46 } da_priv_t;
  47
  48 //! rather arbitrary value for maximum length of wav-format headers
  49 #define MAX_WAVHDR_LEN (1 * 1024 * 1024)
  50
  51 //! how many valid frames in a row we need before accepting as valid MP3
  52 #define MIN_MP3_HDRS 12
  53
  54 //! Used to describe a potential (chain of) MP3 headers we found
  55 typedef struct mp3_hdr {
  56   off_t frame_pos; // start of first frame in this "chain" of headers
  57   off_t next_frame_pos; // here we expect the next header with same parameters
  58   int mp3_chans;
  59   int mp3_freq;
  60   int mpa_spf;
  61   int mpa_layer;
  62   int mpa_br;
  63   int cons_hdrs; // if this reaches MIN_MP3_HDRS we accept as MP3 file
  64   struct mp3_hdr *next;
  65 } mp3_hdr_t;
  66
  67 /**
  68  * \brief free a list of MP3 header descriptions
  69  * \param list pointer to the head-of-list pointer
  70  */
  71 static void free_mp3_hdrs(mp3_hdr_t **list) {
  72   mp3_hdr_t *tmp;
  73   while (*list) {
  74     tmp = (*list)->next;
  75     free(*list);
  76     *list = tmp;
  77   }
  78 }
  79
  80 /**
  81  * \brief add another potential MP3 header to our list
  82  * If it fits into an existing chain this one is expanded otherwise
  83  * a new one is created.
  84  * All entries that expected a MP3 header before the current position
  85  * are discarded.
  86  * The list is expected to be and will be kept sorted by next_frame_pos
  87  * and when those are equal by frame_pos.
  88  * \param list pointer to the head-of-list pointer
  89  * \param st_pos stream position where the described header starts
  90  * \param mp3_chans number of channels as specified by the header (*)
  91  * \param mp3_freq sampling frequency as specified by the header (*)
  92  * \param mpa_spf frame size as specified by the header
  93  * \param mpa_layer layer type ("version") as specified by the header (*)
  94  * \param mpa_br bitrate as specified by the header
  95  * \param mp3_flen length of the frame as specified by the header
  96  * \return If non-null the current file is accepted as MP3 and the
  97  * mp3_hdr struct describing the valid chain is returned. Must be
  98  * freed independent of the list.
  99  *
 100  * parameters marked by (*) must be the same for all headers in the same chain
 101  */
 102 static mp3_hdr_t *add_mp3_hdr(mp3_hdr_t **list, off_t st_pos,
 103                                int mp3_chans, int mp3_freq, int mpa_spf,
 104                                int mpa_layer, int mpa_br, int mp3_flen) {
 105   mp3_hdr_t *tmp;
 106   int in_list = 0;
 107   while (*list && (*list)->next_frame_pos <= st_pos) {
 108     if (((*list)->next_frame_pos < st_pos) || ((*list)->mp3_chans != mp3_chans)
 109          || ((*list)->mp3_freq != mp3_freq) || ((*list)->mpa_layer != mpa_layer) ) {
 110       // wasn't valid!
 111       tmp = (*list)->next;
 112       free(*list);
 113       *list = tmp;
 114     } else {
 115       (*list)->cons_hdrs++;
 116       (*list)->next_frame_pos = st_pos + mp3_flen;
 117       (*list)->mpa_spf = mpa_spf;
 118       (*list)->mpa_br = mpa_br;
 119       if ((*list)->cons_hdrs >= MIN_MP3_HDRS) {
 120         // copy the valid entry, so that the list can be easily freed
 121         tmp = malloc(sizeof(mp3_hdr_t));
 122         memcpy(tmp, *list, sizeof(mp3_hdr_t));
 123         tmp->next = NULL;
 124         return tmp;
 125       }
 126       in_list = 1;
 127       list = &((*list)->next);
 128     }
 129   }
 130   if (!in_list) { // does not belong into an existing chain, insert
 131     // find right position to insert to keep sorting
 132     while (*list && (*list)->next_frame_pos <= st_pos + mp3_flen)
 133       list = &((*list)->next);
 134     tmp = malloc(sizeof(mp3_hdr_t));
 135     tmp->frame_pos = st_pos;
 136     tmp->next_frame_pos = st_pos + mp3_flen;
 137     tmp->mp3_chans = mp3_chans;
 138     tmp->mp3_freq = mp3_freq;
 139     tmp->mpa_spf = mpa_spf;
 140     tmp->mpa_layer = mpa_layer;
 141     tmp->mpa_br = mpa_br;
 142     tmp->cons_hdrs = 1;
 143     tmp->next = *list;
 144     *list = tmp;
 145   }
 146   return NULL;
 147 }
 148
 149 #if 0 /* this code is a mess, clean it up before reenabling */
 150 #define FLAC_SIGNATURE_SIZE 4
 151 #define FLAC_STREAMINFO_SIZE 34
 152 #define FLAC_SEEKPOINT_SIZE 18
 153
 154 enum {
 155   FLAC_STREAMINFO = 0,
 156   FLAC_PADDING,
 157   FLAC_APPLICATION,
 158   FLAC_SEEKTABLE,
 159   FLAC_VORBIS_COMMENT,
 160   FLAC_CUESHEET
 161 } flac_preamble_t;
 162
 163 static void
 164 get_flac_metadata (demuxer_t* demuxer)
 165 {
 166   uint8_t preamble[4];
 167   unsigned int blk_len;
 168   stream_t *s = demuxer->stream;
 169
 170   /* file is qualified; skip over the signature bytes in the stream */
 171   stream_seek (s, 4);
 172
 173   /* loop through the metadata blocks; use a do-while construct since there
 174    * will always be 1 metadata block */
 175   do {
 176     int r;
 177
 178     r = stream_read (s, (char *) preamble, FLAC_SIGNATURE_SIZE);
 179     if (r != FLAC_SIGNATURE_SIZE)
 180       return;
 181
 182     blk_len = AV_RB24(preamble + 1);
 183
 184     switch (preamble[0] & 0x7F)
 185     {
 186     case FLAC_VORBIS_COMMENT:
 187     {
 188       /* For a description of the format please have a look at */
 189       /* http://www.xiph.org/vorbis/doc/v-comment.html */
 190
 191       uint32_t length, comment_list_len;
 192       char comments[blk_len];
 193       uint8_t *ptr = comments;
 194       char *comment;
 195       int cn;
 196       char c;
 197
 198       if (stream_read (s, comments, blk_len) == blk_len)
 199       {
 200         length = AV_RL32(ptr);
 201         ptr += 4 + length;
 202
 203         comment_list_len = AV_RL32(ptr);
 204         ptr += 4;
 205
 206         cn = 0;
 207         for (; cn < comment_list_len; cn++)
 208         {
 209           length = AV_RL32(ptr);
 210           ptr += 4;
 211
 212           comment = ptr;
 213           if (&comment[length] < comments || &comment[length] >= &comments[blk_len])
 214             return;
 215           c = comment[length];
 216           comment[length] = 0;
 217
 218           if (!strncasecmp ("TITLE=", comment, 6) && (length - 6 > 0))
 219             demux_info_add (demuxer, "Title", comment + 6);
 220           else if (!strncasecmp ("ARTIST=", comment, 7) && (length - 7 > 0))
 221             demux_info_add (demuxer, "Artist", comment + 7);
 222           else if (!strncasecmp ("ALBUM=", comment, 6) && (length - 6 > 0))
 223             demux_info_add (demuxer, "Album", comment + 6);
 224           else if (!strncasecmp ("DATE=", comment, 5) && (length - 5 > 0))
 225             demux_info_add (demuxer, "Year", comment + 5);
 226           else if (!strncasecmp ("GENRE=", comment, 6) && (length - 6 > 0))
 227             demux_info_add (demuxer, "Genre", comment + 6);
 228           else if (!strncasecmp ("Comment=", comment, 8) && (length - 8 > 0))
 229             demux_info_add (demuxer, "Comment", comment + 8);
 230           else if (!strncasecmp ("TRACKNUMBER=", comment, 12)
 231                    && (length - 12 > 0))
 232           {
 233             char buf[31];
 234             buf[30] = '\0';
 235             sprintf (buf, "%d", atoi (comment + 12));
 236             demux_info_add(demuxer, "Track", buf);
 237           }
 238           comment[length] = c;
 239
 240           ptr += length;
 241         }
 242       }
 243       break;
 244     }
 245
 246     case FLAC_STREAMINFO:
 247     case FLAC_PADDING:
 248     case FLAC_APPLICATION:
 249     case FLAC_SEEKTABLE:
 250     case FLAC_CUESHEET:
 251     default:
 252       /* 6-127 are presently reserved */
 253       stream_skip (s, blk_len);
 254       break;
 255     }
 256   } while ((preamble[0] & 0x80) == 0);
 257 }
 258 #endif
 259
 260 static int demux_audio_open(demuxer_t* demuxer) {
 261   stream_t *s;
 262   sh_audio_t* sh_audio;
 263   uint8_t hdr[HDR_SIZE];
 264   int frmt = 0, n = 0, step;
 265   off_t st_pos = 0, next_frame_pos = 0;
 266   // mp3_hdrs list is sorted first by next_frame_pos and then by frame_pos
 267   mp3_hdr_t *mp3_hdrs = NULL, *mp3_found = NULL;
 268   da_priv_t* priv;
 269
 270   s = demuxer->stream;
 271
 272   stream_read(s, hdr, HDR_SIZE);
 273   while(n < 30000 && !s->eof) {
 274     int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
 275     st_pos = stream_tell(s) - HDR_SIZE;
 276     step = 1;
 277
 278     if( hdr[0] == 'R' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == 'F' ) {
 279       stream_skip(s,4);
 280       if(s->eof)
 281         break;
 282       stream_read(s,hdr,4);
 283       if(s->eof)
 284         break;
 285       if(hdr[0] != 'W' || hdr[1] != 'A' || hdr[2] != 'V'  || hdr[3] != 'E' )
 286         stream_skip(s,-8);
 287       else
 288       // We found wav header. Now we can have 'fmt ' or a mp3 header
 289       // empty the buffer
 290         step = 4;
 291     } else if( hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3' && (hdr[3] >= 2)) {
 292       int len;
 293       stream_skip(s,2);
 294       stream_read(s,hdr,4);
 295       len = (hdr[0]<<21) | (hdr[1]<<14) | (hdr[2]<<7) | hdr[3];
 296       stream_skip(s,len);
 297       step = 4;
 298     } else if( hdr[0] == 'f' && hdr[1] == 'm' && hdr[2] == 't' && hdr[3] == ' ' ) {
 299       frmt = WAV;
 300       break;
 301     } else if((mp3_flen = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
 302                                 &mpa_spf, &mpa_layer, &mpa_br)) > 0) {
 303       mp3_found = add_mp3_hdr(&mp3_hdrs, st_pos, mp3_chans, mp3_freq,
 304                               mpa_spf, mpa_layer, mpa_br, mp3_flen);
 305       if (mp3_found) {
 306         frmt = MP3;
 307         break;
 308       }
 309     } else if( hdr[0] == 'f' && hdr[1] == 'L' && hdr[2] == 'a' && hdr[3] == 'C' ) {
 310       frmt = fLaC;
 311       if (!mp3_hdrs || mp3_hdrs->cons_hdrs < 3)
 312         break;
 313     }
 314     // Add here some other audio format detection
 315     if(step < HDR_SIZE)
 316       memmove(hdr,&hdr[step],HDR_SIZE-step);
 317     stream_read(s, &hdr[HDR_SIZE - step], step);
 318     n++;
 319   }
 320
 321   free_mp3_hdrs(&mp3_hdrs);
 322
 323   if(!frmt)
 324     return 0;
 325
 326   sh_audio = new_sh_audio(demuxer,0);
 327
 328   switch(frmt) {
 329   case MP3:
 330     sh_audio->format = (mp3_found->mpa_layer < 3 ? 0x50 : 0x55);
 331     demuxer->movi_start = mp3_found->frame_pos;
 332     next_frame_pos = mp3_found->next_frame_pos;
 333     sh_audio->audio.dwSampleSize= 0;
 334     sh_audio->audio.dwScale = mp3_found->mpa_spf;
 335     sh_audio->audio.dwRate = mp3_found->mp3_freq;
 336     sh_audio->wf = malloc(sizeof(*sh_audio->wf));
 337     sh_audio->wf->wFormatTag = sh_audio->format;
 338     sh_audio->wf->nChannels = mp3_found->mp3_chans;
 339     sh_audio->wf->nSamplesPerSec = mp3_found->mp3_freq;
 340     sh_audio->wf->nAvgBytesPerSec = mp3_found->mpa_br * (1000 / 8);
 341     sh_audio->wf->nBlockAlign = mp3_found->mpa_spf;
 342     sh_audio->wf->wBitsPerSample = 16;
 343     sh_audio->wf->cbSize = 0;
 344     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 345     free(mp3_found);
 346     mp3_found = NULL;
 347     if(s->end_pos && (s->flags & MP_STREAM_SEEK) == MP_STREAM_SEEK) {
 348       char tag[4];
 349       stream_seek(s,s->end_pos-128);
 350       stream_read(s,tag,3);
 351       tag[3] = '\0';
 352       if(strcmp(tag,"TAG"))
 353         demuxer->movi_end = s->end_pos;
 354       else {
 355         char buf[31];
 356         uint8_t g;
 357         demuxer->movi_end = stream_tell(s)-3;
 358         stream_read(s,buf,30);
 359         buf[30] = '\0';
 360         demux_info_add(demuxer,"Title",buf);
 361         stream_read(s,buf,30);
 362         buf[30] = '\0';
 363         demux_info_add(demuxer,"Artist",buf);
 364         stream_read(s,buf,30);
 365         buf[30] = '\0';
 366         demux_info_add(demuxer,"Album",buf);
 367         stream_read(s,buf,4);
 368         buf[4] = '\0';
 369         demux_info_add(demuxer,"Year",buf);
 370         stream_read(s,buf,30);
 371         buf[30] = '\0';
 372         demux_info_add(demuxer,"Comment",buf);
 373         if(buf[28] == 0 && buf[29] != 0) {
 374           uint8_t trk = (uint8_t)buf[29];
 375           sprintf(buf,"%d",trk);
 376           demux_info_add(demuxer,"Track",buf);
 377         }
 378         g = stream_read_char(s);
 379         demux_info_add(demuxer,"Genre",genres[g]);
 380       }
 381     }
 382     break;
 383   case WAV: {
 384     unsigned int chunk_type;
 385     unsigned int chunk_size;
 386     WAVEFORMATEX* w;
 387     int l;
 388     l = stream_read_dword_le(s);
 389     if(l < 16) {
 390       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too short (%d)!!!\n",l);
 391       l = 16;
 392     }
 393     if(l > MAX_WAVHDR_LEN) {
 394       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too long (%d)!!!\n",l);
 395       l = 16;
 396     }
 397     sh_audio->wf = w = malloc(l > sizeof(*w) ? l : sizeof(*w));
 398     w->wFormatTag = sh_audio->format = stream_read_word_le(s);
 399     w->nChannels = sh_audio->channels = stream_read_word_le(s);
 400     w->nSamplesPerSec = sh_audio->samplerate = stream_read_dword_le(s);
 401     w->nAvgBytesPerSec = stream_read_dword_le(s);
 402     w->nBlockAlign = stream_read_word_le(s);
 403     w->wBitsPerSample = stream_read_word_le(s);
 404     sh_audio->samplesize = (w->wBitsPerSample + 7) / 8;
 405     w->cbSize = 0;
 406     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 407     l -= 16;
 408     if (l >= 2) {
 409       w->cbSize = stream_read_word_le(s);
 410       l -= 2;
 411       if (l < w->cbSize) {
 412         mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] truncated extradata (%d < %d)\n",
 413                l,w->cbSize);
 414         w->cbSize = l;
 415       }
 416       stream_read(s,(char*)(w + 1),w->cbSize);
 417       l -= w->cbSize;
 418       if (w->wFormatTag == 0xfffe && w->cbSize >= 22)
 419           sh_audio->format = le2me_16(((WAVEFORMATEXTENSIBLE *)w)->SubFormat);
 420     }
 421
 422     if( mp_msg_test(MSGT_DEMUX,MSGL_V) ) print_wave_header(w, MSGL_V);
 423     if(l)
 424       stream_skip(s,l);
 425     do
 426     {
 427       chunk_type = stream_read_fourcc(demuxer->stream);
 428       chunk_size = stream_read_dword_le(demuxer->stream);
 429       if (chunk_type != mmioFOURCC('d', 'a', 't', 'a'))
 430         stream_skip(demuxer->stream, chunk_size);
 431     } while (!s->eof && chunk_type != mmioFOURCC('d', 'a', 't', 'a'));
 432     demuxer->movi_start = stream_tell(s);
 433     demuxer->movi_end = chunk_size ? demuxer->movi_start + chunk_size : s->end_pos;
 434 //    printf("wav: %X .. %X\n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 435     // Check if it contains dts audio
 436     if((w->wFormatTag == 0x01) && (w->nChannels == 2) && (w->nSamplesPerSec == 44100)) {
 437         unsigned char buf[16384]; // vlc uses 16384*4 (4 dts frames)
 438         unsigned int i;
 439         memset(buf, 0, sizeof(buf));
 440         stream_read(s, buf, sizeof(buf));
 441         for (i = 0; i < sizeof(buf) - 5; i += 2) {
 442             // DTS, 14 bit, LE
 443             if((buf[i] == 0xff) && (buf[i+1] == 0x1f) && (buf[i+2] == 0x00) &&
 444                (buf[i+3] == 0xe8) && ((buf[i+4] & 0xfe) == 0xf0) && (buf[i+5] == 0x07)) {
 445                 sh_audio->format = 0x2001;
 446                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, LE\n");
 447                 break;
 448             }
 449             // DTS, 14 bit, BE
 450             if((buf[i] == 0x1f) && (buf[i+1] == 0xff) && (buf[i+2] == 0xe8) &&
 451                (buf[i+3] == 0x00) && (buf[i+4] == 0x07) && ((buf[i+5] & 0xfe) == 0xf0)) {
 452                 sh_audio->format = 0x2001;
 453                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, BE\n");
 454                 break;
 455             }
 456             // DTS, 16 bit, BE
 457             if((buf[i] == 0x7f) && (buf[i+1] == 0xfe) && (buf[i+2] == 0x80) &&
 458                (buf[i+3] == 0x01)) {
 459                 sh_audio->format = 0x2001;
 460                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, BE\n");
 461                 break;
 462             }
 463             // DTS, 16 bit, LE
 464             if((buf[i] == 0xfe) && (buf[i+1] == 0x7f) && (buf[i+2] == 0x01) &&
 465                (buf[i+3] == 0x80)) {
 466                 sh_audio->format = 0x2001;
 467                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, LE\n");
 468                 break;
 469             }
 470         }
 471         if (sh_audio->format == 0x2001) {
 472             sh_audio->needs_parsing = 1;
 473             mp_msg(MSGT_DEMUX,MSGL_DBG2,"[demux_audio] DTS sync offset = %u\n", i);
 474         }
 475
 476     }
 477     stream_seek(s,demuxer->movi_start);
 478   } break;
 479   case fLaC:
 480             sh_audio->format = mmioFOURCC('f', 'L', 'a', 'C');
 481             demuxer->movi_start = stream_tell(s) - 4;
 482             demuxer->movi_end = s->end_pos;
 483             if (demuxer->movi_end > demuxer->movi_start) {
 484               // try to find out approx. bitrate
 485               int64_t size = demuxer->movi_end - demuxer->movi_start;
 486               int64_t num_samples;
 487               int32_t srate;
 488               stream_skip(s, 14);
 489               srate = stream_read_int24(s) >> 4;
 490               num_samples  = stream_read_int24(s) << 16;
 491               num_samples |= stream_read_word(s);
 492               if (num_samples && srate)
 493                 sh_audio->i_bps = size * srate / num_samples;
 494             }
 495             if (sh_audio->i_bps < 1) // guess value to prevent crash
 496               sh_audio->i_bps = 64 * 1024;
 497             sh_audio->needs_parsing = 1;
 498 //          get_flac_metadata (demuxer);
 499             break;
 500   }
 501
 502   priv = malloc(sizeof(da_priv_t));
 503   priv->frmt = frmt;
 504   priv->next_pts = 0;
 505   demuxer->priv = priv;
 506   demuxer->audio->id = 0;
 507   demuxer->audio->sh = sh_audio;
 508   sh_audio->ds = demuxer->audio;
 509   sh_audio->samplerate = sh_audio->audio.dwRate;
 510
 511   if(stream_tell(s) != demuxer->movi_start)
 512   {
 513     mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking from 0x%X to start pos 0x%X\n",
 514             (int)stream_tell(s), (int)demuxer->movi_start);
 515     stream_seek(s,demuxer->movi_start);
 516     if (stream_tell(s) != demuxer->movi_start) {
 517       mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking failed, now at 0x%X!\n",
 518               (int)stream_tell(s));
 519       if (next_frame_pos) {
 520         mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking to 0x%X instead\n",
 521                 (int)next_frame_pos);
 522         stream_seek(s, next_frame_pos);
 523       }
 524     }
 525   }
 526
 527   mp_msg(MSGT_DEMUX,MSGL_V,"demux_audio: audio data 0x%X - 0x%X  \n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 528
 529   return DEMUXER_TYPE_AUDIO;
 530 }
 531
 532
 533 static int demux_audio_fill_buffer(demuxer_t *demux, demux_stream_t *ds) {
 534   int l;
 535   demux_packet_t* dp;
 536   sh_audio_t* sh_audio = ds->sh;
 537   da_priv_t* priv = demux->priv;
 538   double this_pts = priv->next_pts;
 539   stream_t* s = demux->stream;
 540
 541   if(s->eof)
 542     return 0;
 543
 544   switch(priv->frmt) {
 545   case MP3 :
 546     while(1) {
 547       uint8_t hdr[4];
 548       stream_read(s,hdr,4);
 549       if (s->eof)
 550         return 0;
 551       l = mp_decode_mp3_header(hdr);
 552       if(l < 0) {
 553         if (demux->movi_end && stream_tell(s) >= demux->movi_end)
 554           return 0; // might be ID3 tag, i.e. EOF
 555         stream_skip(s,-3);
 556       } else {
 557         dp = new_demux_packet(l);
 558         memcpy(dp->buffer,hdr,4);
 559         if (stream_read(s,dp->buffer + 4,l-4) != l-4)
 560         {
 561           free_demux_packet(dp);
 562           return 0;
 563         }
 564         priv->next_pts += sh_audio->audio.dwScale/(double)sh_audio->samplerate;
 565         break;
 566       }
 567     } break;
 568   case WAV : {
 569     unsigned align = sh_audio->wf->nBlockAlign;
 570     l = sh_audio->wf->nAvgBytesPerSec;
 571     if (l <= 0) l = 65536;
 572     if (demux->movi_end && l > demux->movi_end - stream_tell(s)) {
 573       // do not read beyond end, there might be junk after data chunk
 574       l = demux->movi_end - stream_tell(s);
 575       if (l <= 0) return 0;
 576     }
 577     if (align)
 578       l = (l + align - 1) / align * align;
 579     dp = new_demux_packet(l);
 580     l = stream_read(s,dp->buffer,l);
 581     priv->next_pts += l/(double)sh_audio->i_bps;
 582     break;
 583   }
 584   case fLaC: {
 585     l = 65535;
 586     dp = new_demux_packet(l);
 587     l = stream_read(s,dp->buffer,l);
 588     priv->next_pts = MP_NOPTS_VALUE;
 589     break;
 590   }
 591   default:
 592     mp_tmsg(MSGT_DEMUXER,MSGL_WARN,"Audio demuxer: unknown format %d.\n",priv->frmt);
 593     return 0;
 594   }
 595
 596   resize_demux_packet(dp, l);
 597   dp->pts = this_pts;
 598   ds_add_packet(ds, dp);
 599   return 1;
 600 }
 601
 602 static void high_res_mp3_seek(demuxer_t *demuxer,float time) {
 603   uint8_t hdr[4];
 604   int len,nf;
 605   da_priv_t* priv = demuxer->priv;
 606   sh_audio_t* sh = (sh_audio_t*)demuxer->audio->sh;
 607
 608   nf = time*sh->samplerate/sh->audio.dwScale;
 609   while(nf > 0) {
 610     stream_read(demuxer->stream,hdr,4);
 611     len = mp_decode_mp3_header(hdr);
 612     if(len < 0) {
 613       stream_skip(demuxer->stream,-3);
 614       continue;
 615     }
 616     stream_skip(demuxer->stream,len-4);
 617     priv->next_pts += sh->audio.dwScale/(double)sh->samplerate;
 618     nf--;
 619   }
 620 }
 621
 622 static void demux_audio_seek(demuxer_t *demuxer,float rel_seek_secs,float audio_delay,int flags){
 623   struct MPOpts *opts = demuxer->opts;
 624   sh_audio_t* sh_audio;
 625   stream_t* s;
 626   int64_t base,pos;
 627   float len;
 628   da_priv_t* priv;
 629
 630   if(!(sh_audio = demuxer->audio->sh))
 631     return;
 632   s = demuxer->stream;
 633   priv = demuxer->priv;
 634
 635   if(priv->frmt == MP3 && opts->hr_mp3_seek && !(flags & SEEK_FACTOR)) {
 636     len = (flags & SEEK_ABSOLUTE) ? rel_seek_secs - priv->next_pts : rel_seek_secs;
 637     if(len < 0) {
 638       stream_seek(s,demuxer->movi_start);
 639       len = priv->next_pts + len;
 640       priv->next_pts = 0;
 641     }
 642     if(len > 0)
 643       high_res_mp3_seek(demuxer,len);
 644     return;
 645   }
 646
 647   base = flags&SEEK_ABSOLUTE ? demuxer->movi_start : stream_tell(s);
 648   if(flags&SEEK_FACTOR)
 649     pos = base + ((demuxer->movi_end - demuxer->movi_start)*rel_seek_secs);
 650   else
 651     pos = base + (rel_seek_secs*sh_audio->i_bps);
 652
 653   if(demuxer->movi_end && pos >= demuxer->movi_end) {
 654      pos = demuxer->movi_end;
 655   } else if(pos < demuxer->movi_start)
 656     pos = demuxer->movi_start;
 657
 658   priv->next_pts = (pos-demuxer->movi_start)/(double)sh_audio->i_bps;
 659
 660   switch(priv->frmt) {
 661   case WAV:
 662     pos -= (pos - demuxer->movi_start) %
 663             (sh_audio->wf->nBlockAlign ? sh_audio->wf->nBlockAlign :
 664              (sh_audio->channels * sh_audio->samplesize));
 665     break;
 666   }
 667
 668   stream_seek(s,pos);
 669 }
 670
 671 static void demux_close_audio(demuxer_t* demuxer) {
 672   da_priv_t* priv = demuxer->priv;
 673
 674   free(priv);
 675 }
 676
 677 static int demux_audio_control(demuxer_t *demuxer,int cmd, void *arg){
 678     sh_audio_t *sh_audio=demuxer->audio->sh;
 679     int audio_length = sh_audio->i_bps ? demuxer->movi_end / sh_audio->i_bps : 0;
 680     da_priv_t* priv = demuxer->priv;
 681
 682     switch(cmd) {
 683         case DEMUXER_CTRL_GET_TIME_LENGTH:
 684             if (audio_length<=0) return DEMUXER_CTRL_DONTKNOW;
 685             *((double *)arg)=(double)audio_length;
 686             return DEMUXER_CTRL_GUESS;
 687
 688         case DEMUXER_CTRL_GET_PERCENT_POS:
 689             if (audio_length<=0)
 690                 return DEMUXER_CTRL_DONTKNOW;
 691             *((int *)arg)=(int)( (priv->next_pts*100)  / audio_length);
 692             return DEMUXER_CTRL_OK;
 693
 694         default:
 695             return DEMUXER_CTRL_NOTIMPL;
 696     }
 697 }
 698
 699
 700 const demuxer_desc_t demuxer_desc_audio = {
 701   "Audio demuxer",
 702   "audio",
 703   "Audio only",
 704   "?",
 705   "Audio only files",
 706   DEMUXER_TYPE_AUDIO,
 707   0, // unsafe autodetect
 708   demux_audio_open,
 709   demux_audio_fill_buffer,
 710   NULL,
 711   demux_close_audio,
 712   demux_audio_seek,
 713   demux_audio_control
 714 };