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 "config.h"
  20 #include "mp_msg.h"
  21 #include "help_mp.h"
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include "stream/stream.h"
  26 #include "aviprint.h"
  27 #include "demuxer.h"
  28 #include "stheader.h"
  29 #include "genres.h"
  30 #include "mp3_hdr.h"
  31 #include "libavutil/intreadwrite.h"
  32
  33 #include <string.h>
  34
  35 #define MP3 1
  36 #define WAV 2
  37 #define fLaC 3
  38
  39
  40 #define HDR_SIZE 4
  41
  42 typedef struct da_priv {
  43   int frmt;
  44   double next_pts;
  45 } da_priv_t;
  46
  47 //! rather arbitrary value for maximum length of wav-format headers
  48 #define MAX_WAVHDR_LEN (1 * 1024 * 1024)
  49
  50 //! how many valid frames in a row we need before accepting as valid MP3
  51 #define MIN_MP3_HDRS 12
  52
  53 //! Used to describe a potential (chain of) MP3 headers we found
  54 typedef struct mp3_hdr {
  55   off_t frame_pos; // start of first frame in this "chain" of headers
  56   off_t next_frame_pos; // here we expect the next header with same parameters
  57   int mp3_chans;
  58   int mp3_freq;
  59   int mpa_spf;
  60   int mpa_layer;
  61   int mpa_br;
  62   int cons_hdrs; // if this reaches MIN_MP3_HDRS we accept as MP3 file
  63   struct mp3_hdr *next;
  64 } mp3_hdr_t;
  65
  66 int hr_mp3_seek = 0;
  67
  68 /**
  69  * \brief free a list of MP3 header descriptions
  70  * \param list pointer to the head-of-list pointer
  71  */
  72 static void free_mp3_hdrs(mp3_hdr_t **list) {
  73   mp3_hdr_t *tmp;
  74   while (*list) {
  75     tmp = (*list)->next;
  76     free(*list);
  77     *list = tmp;
  78   }
  79 }
  80
  81 /**
  82  * \brief add another potential MP3 header to our list
  83  * If it fits into an existing chain this one is expanded otherwise
  84  * a new one is created.
  85  * All entries that expected a MP3 header before the current position
  86  * are discarded.
  87  * The list is expected to be and will be kept sorted by next_frame_pos
  88  * and when those are equal by frame_pos.
  89  * \param list pointer to the head-of-list pointer
  90  * \param st_pos stream position where the described header starts
  91  * \param mp3_chans number of channels as specified by the header (*)
  92  * \param mp3_freq sampling frequency as specified by the header (*)
  93  * \param mpa_spf frame size as specified by the header
  94  * \param mpa_layer layer type ("version") as specified by the header (*)
  95  * \param mpa_br bitrate as specified by the header
  96  * \param mp3_flen length of the frame as specified by the header
  97  * \return If non-null the current file is accepted as MP3 and the
  98  * mp3_hdr struct describing the valid chain is returned. Must be
  99  * freed independent of the list.
 100  *
 101  * parameters marked by (*) must be the same for all headers in the same chain
 102  */
 103 static mp3_hdr_t *add_mp3_hdr(mp3_hdr_t **list, off_t st_pos,
 104                                int mp3_chans, int mp3_freq, int mpa_spf,
 105                                int mpa_layer, int mpa_br, int mp3_flen) {
 106   mp3_hdr_t *tmp;
 107   int in_list = 0;
 108   while (*list && (*list)->next_frame_pos <= st_pos) {
 109     if (((*list)->next_frame_pos < st_pos) || ((*list)->mp3_chans != mp3_chans)
 110          || ((*list)->mp3_freq != mp3_freq) || ((*list)->mpa_layer != mpa_layer) ) {
 111       // wasn't valid!
 112       tmp = (*list)->next;
 113       free(*list);
 114       *list = tmp;
 115     } else {
 116       (*list)->cons_hdrs++;
 117       (*list)->next_frame_pos = st_pos + mp3_flen;
 118       (*list)->mpa_spf = mpa_spf;
 119       (*list)->mpa_br = mpa_br;
 120       if ((*list)->cons_hdrs >= MIN_MP3_HDRS) {
 121         // copy the valid entry, so that the list can be easily freed
 122         tmp = malloc(sizeof(mp3_hdr_t));
 123         memcpy(tmp, *list, sizeof(mp3_hdr_t));
 124         tmp->next = NULL;
 125         return tmp;
 126       }
 127       in_list = 1;
 128       list = &((*list)->next);
 129     }
 130   }
 131   if (!in_list) { // does not belong into an existing chain, insert
 132     // find right position to insert to keep sorting
 133     while (*list && (*list)->next_frame_pos <= st_pos + mp3_flen)
 134       list = &((*list)->next);
 135     tmp = malloc(sizeof(mp3_hdr_t));
 136     tmp->frame_pos = st_pos;
 137     tmp->next_frame_pos = st_pos + mp3_flen;
 138     tmp->mp3_chans = mp3_chans;
 139     tmp->mp3_freq = mp3_freq;
 140     tmp->mpa_spf = mpa_spf;
 141     tmp->mpa_layer = mpa_layer;
 142     tmp->mpa_br = mpa_br;
 143     tmp->cons_hdrs = 1;
 144     tmp->next = *list;
 145     *list = tmp;
 146   }
 147   return NULL;
 148 }
 149
 150 #if 0 /* this code is a mess, clean it up before reenabling */
 151 #define FLAC_SIGNATURE_SIZE 4
 152 #define FLAC_STREAMINFO_SIZE 34
 153 #define FLAC_SEEKPOINT_SIZE 18
 154
 155 enum {
 156   FLAC_STREAMINFO = 0,
 157   FLAC_PADDING,
 158   FLAC_APPLICATION,
 159   FLAC_SEEKTABLE,
 160   FLAC_VORBIS_COMMENT,
 161   FLAC_CUESHEET
 162 } flac_preamble_t;
 163
 164 static void
 165 get_flac_metadata (demuxer_t* demuxer)
 166 {
 167   uint8_t preamble[4];
 168   unsigned int blk_len;
 169   stream_t *s = demuxer->stream;
 170
 171   /* file is qualified; skip over the signature bytes in the stream */
 172   stream_seek (s, 4);
 173
 174   /* loop through the metadata blocks; use a do-while construct since there
 175    * will always be 1 metadata block */
 176   do {
 177     int r;
 178
 179     r = stream_read (s, (char *) preamble, FLAC_SIGNATURE_SIZE);
 180     if (r != FLAC_SIGNATURE_SIZE)
 181       return;
 182
 183     blk_len = AV_RB24(preamble + 1);
 184
 185     switch (preamble[0] & 0x7F)
 186     {
 187     case FLAC_VORBIS_COMMENT:
 188     {
 189       /* For a description of the format please have a look at */
 190       /* http://www.xiph.org/vorbis/doc/v-comment.html */
 191
 192       uint32_t length, comment_list_len;
 193       char comments[blk_len];
 194       uint8_t *ptr = comments;
 195       char *comment;
 196       int cn;
 197       char c;
 198
 199       if (stream_read (s, comments, blk_len) == blk_len)
 200       {
 201         length = AV_RL32(ptr);
 202         ptr += 4 + length;
 203
 204         comment_list_len = AV_RL32(ptr);
 205         ptr += 4;
 206
 207         cn = 0;
 208         for (; cn < comment_list_len; cn++)
 209         {
 210           length = AV_RL32(ptr);
 211           ptr += 4;
 212
 213           comment = ptr;
 214           if (&comment[length] < comments || &comment[length] >= &comments[blk_len])
 215             return;
 216           c = comment[length];
 217           comment[length] = 0;
 218
 219           if (!strncasecmp ("TITLE=", comment, 6) && (length - 6 > 0))
 220             demux_info_add (demuxer, "Title", comment + 6);
 221           else if (!strncasecmp ("ARTIST=", comment, 7) && (length - 7 > 0))
 222             demux_info_add (demuxer, "Artist", comment + 7);
 223           else if (!strncasecmp ("ALBUM=", comment, 6) && (length - 6 > 0))
 224             demux_info_add (demuxer, "Album", comment + 6);
 225           else if (!strncasecmp ("DATE=", comment, 5) && (length - 5 > 0))
 226             demux_info_add (demuxer, "Year", comment + 5);
 227           else if (!strncasecmp ("GENRE=", comment, 6) && (length - 6 > 0))
 228             demux_info_add (demuxer, "Genre", comment + 6);
 229           else if (!strncasecmp ("Comment=", comment, 8) && (length - 8 > 0))
 230             demux_info_add (demuxer, "Comment", comment + 8);
 231           else if (!strncasecmp ("TRACKNUMBER=", comment, 12)
 232                    && (length - 12 > 0))
 233           {
 234             char buf[31];
 235             buf[30] = '\0';
 236             sprintf (buf, "%d", atoi (comment + 12));
 237             demux_info_add(demuxer, "Track", buf);
 238           }
 239           comment[length] = c;
 240
 241           ptr += length;
 242         }
 243       }
 244       break;
 245     }
 246
 247     case FLAC_STREAMINFO:
 248     case FLAC_PADDING:
 249     case FLAC_APPLICATION:
 250     case FLAC_SEEKTABLE:
 251     case FLAC_CUESHEET:
 252     default:
 253       /* 6-127 are presently reserved */
 254       stream_skip (s, blk_len);
 255       break;
 256     }
 257   } while ((preamble[0] & 0x80) == 0);
 258 }
 259 #endif
 260
 261 static int demux_audio_open(demuxer_t* demuxer) {
 262   stream_t *s;
 263   sh_audio_t* sh_audio;
 264   uint8_t hdr[HDR_SIZE];
 265   int frmt = 0, n = 0, step;
 266   off_t st_pos = 0, next_frame_pos = 0;
 267   // mp3_hdrs list is sorted first by next_frame_pos and then by frame_pos
 268   mp3_hdr_t *mp3_hdrs = NULL, *mp3_found = NULL;
 269   da_priv_t* priv;
 270
 271   s = demuxer->stream;
 272
 273   stream_read(s, hdr, HDR_SIZE);
 274   while(n < 30000 && !s->eof) {
 275     int mp3_freq, mp3_chans, mp3_flen, mpa_layer, mpa_spf, mpa_br;
 276     st_pos = stream_tell(s) - HDR_SIZE;
 277     step = 1;
 278
 279     if( hdr[0] == 'R' && hdr[1] == 'I' && hdr[2] == 'F' && hdr[3] == 'F' ) {
 280       stream_skip(s,4);
 281       if(s->eof)
 282         break;
 283       stream_read(s,hdr,4);
 284       if(s->eof)
 285         break;
 286       if(hdr[0] != 'W' || hdr[1] != 'A' || hdr[2] != 'V'  || hdr[3] != 'E' )
 287         stream_skip(s,-8);
 288       else
 289       // We found wav header. Now we can have 'fmt ' or a mp3 header
 290       // empty the buffer
 291         step = 4;
 292     } else if( hdr[0] == 'I' && hdr[1] == 'D' && hdr[2] == '3' && (hdr[3] >= 2)) {
 293       int len;
 294       stream_skip(s,2);
 295       stream_read(s,hdr,4);
 296       len = (hdr[0]<<21) | (hdr[1]<<14) | (hdr[2]<<7) | hdr[3];
 297       stream_skip(s,len);
 298       step = 4;
 299     } else if( hdr[0] == 'f' && hdr[1] == 'm' && hdr[2] == 't' && hdr[3] == ' ' ) {
 300       frmt = WAV;
 301       break;
 302     } else if((mp3_flen = mp_get_mp3_header(hdr, &mp3_chans, &mp3_freq,
 303                                 &mpa_spf, &mpa_layer, &mpa_br)) > 0) {
 304       mp3_found = add_mp3_hdr(&mp3_hdrs, st_pos, mp3_chans, mp3_freq,
 305                               mpa_spf, mpa_layer, mpa_br, mp3_flen);
 306       if (mp3_found) {
 307         frmt = MP3;
 308         break;
 309       }
 310     } else if( hdr[0] == 'f' && hdr[1] == 'L' && hdr[2] == 'a' && hdr[3] == 'C' ) {
 311       frmt = fLaC;
 312       if (!mp3_hdrs || mp3_hdrs->cons_hdrs < 3)
 313         break;
 314     }
 315     // Add here some other audio format detection
 316     if(step < HDR_SIZE)
 317       memmove(hdr,&hdr[step],HDR_SIZE-step);
 318     stream_read(s, &hdr[HDR_SIZE - step], step);
 319     n++;
 320   }
 321
 322   free_mp3_hdrs(&mp3_hdrs);
 323
 324   if(!frmt)
 325     return 0;
 326
 327   sh_audio = new_sh_audio(demuxer,0);
 328
 329   switch(frmt) {
 330   case MP3:
 331     sh_audio->format = (mp3_found->mpa_layer < 3 ? 0x50 : 0x55);
 332     demuxer->movi_start = mp3_found->frame_pos;
 333     next_frame_pos = mp3_found->next_frame_pos;
 334     sh_audio->audio.dwSampleSize= 0;
 335     sh_audio->audio.dwScale = mp3_found->mpa_spf;
 336     sh_audio->audio.dwRate = mp3_found->mp3_freq;
 337     sh_audio->wf = malloc(sizeof(WAVEFORMATEX));
 338     sh_audio->wf->wFormatTag = sh_audio->format;
 339     sh_audio->wf->nChannels = mp3_found->mp3_chans;
 340     sh_audio->wf->nSamplesPerSec = mp3_found->mp3_freq;
 341     sh_audio->wf->nAvgBytesPerSec = mp3_found->mpa_br * (1000 / 8);
 342     sh_audio->wf->nBlockAlign = mp3_found->mpa_spf;
 343     sh_audio->wf->wBitsPerSample = 16;
 344     sh_audio->wf->cbSize = 0;
 345     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 346     free(mp3_found);
 347     mp3_found = NULL;
 348     if(s->end_pos && (s->flags & MP_STREAM_SEEK) == MP_STREAM_SEEK) {
 349       char tag[4];
 350       stream_seek(s,s->end_pos-128);
 351       stream_read(s,tag,3);
 352       tag[3] = '\0';
 353       if(strcmp(tag,"TAG"))
 354         demuxer->movi_end = s->end_pos;
 355       else {
 356         char buf[31];
 357         uint8_t g;
 358         demuxer->movi_end = stream_tell(s)-3;
 359         stream_read(s,buf,30);
 360         buf[30] = '\0';
 361         demux_info_add(demuxer,"Title",buf);
 362         stream_read(s,buf,30);
 363         buf[30] = '\0';
 364         demux_info_add(demuxer,"Artist",buf);
 365         stream_read(s,buf,30);
 366         buf[30] = '\0';
 367         demux_info_add(demuxer,"Album",buf);
 368         stream_read(s,buf,4);
 369         buf[4] = '\0';
 370         demux_info_add(demuxer,"Year",buf);
 371         stream_read(s,buf,30);
 372         buf[30] = '\0';
 373         demux_info_add(demuxer,"Comment",buf);
 374         if(buf[28] == 0 && buf[29] != 0) {
 375           uint8_t trk = (uint8_t)buf[29];
 376           sprintf(buf,"%d",trk);
 377           demux_info_add(demuxer,"Track",buf);
 378         }
 379         g = stream_read_char(s);
 380         demux_info_add(demuxer,"Genre",genres[g]);
 381       }
 382     }
 383     break;
 384   case WAV: {
 385     unsigned int chunk_type;
 386     unsigned int chunk_size;
 387     WAVEFORMATEX* w;
 388     int l;
 389     l = stream_read_dword_le(s);
 390     if(l < 16) {
 391       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too short (%d)!!!\n",l);
 392       l = 16;
 393     }
 394     if(l > MAX_WAVHDR_LEN) {
 395       mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] Bad wav header length: too long (%d)!!!\n",l);
 396       l = 16;
 397     }
 398     sh_audio->wf = w = malloc(l > sizeof(WAVEFORMATEX) ? l : sizeof(WAVEFORMATEX));
 399     w->wFormatTag = sh_audio->format = stream_read_word_le(s);
 400     w->nChannels = sh_audio->channels = stream_read_word_le(s);
 401     w->nSamplesPerSec = sh_audio->samplerate = stream_read_dword_le(s);
 402     w->nAvgBytesPerSec = stream_read_dword_le(s);
 403     w->nBlockAlign = stream_read_word_le(s);
 404     w->wBitsPerSample = stream_read_word_le(s);
 405     sh_audio->samplesize = (w->wBitsPerSample + 7) / 8;
 406     w->cbSize = 0;
 407     sh_audio->i_bps = sh_audio->wf->nAvgBytesPerSec;
 408     l -= 16;
 409     if (l >= 2) {
 410       w->cbSize = stream_read_word_le(s);
 411       l -= 2;
 412       if (l < w->cbSize) {
 413         mp_msg(MSGT_DEMUX,MSGL_ERR,"[demux_audio] truncated extradata (%d < %d)\n",
 414                l,w->cbSize);
 415         w->cbSize = l;
 416       }
 417       stream_read(s,(char*)((char*)(w)+sizeof(WAVEFORMATEX)),w->cbSize);
 418       l -= w->cbSize;
 419       if (w->wFormatTag & 0xfffe && w->cbSize >= 22)
 420           sh_audio->format = ((WAVEFORMATEXTENSIBLE *)w)->SubFormat;
 421     }
 422
 423     if( mp_msg_test(MSGT_DEMUX,MSGL_V) ) print_wave_header(w, MSGL_V);
 424     if(l)
 425       stream_skip(s,l);
 426     do
 427     {
 428       chunk_type = stream_read_fourcc(demuxer->stream);
 429       chunk_size = stream_read_dword_le(demuxer->stream);
 430       if (chunk_type != mmioFOURCC('d', 'a', 't', 'a'))
 431         stream_skip(demuxer->stream, chunk_size);
 432     } while (!s->eof && chunk_type != mmioFOURCC('d', 'a', 't', 'a'));
 433     demuxer->movi_start = stream_tell(s);
 434     demuxer->movi_end = chunk_size ? demuxer->movi_start + chunk_size : s->end_pos;
 435 //    printf("wav: %X .. %X\n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 436     // Check if it contains dts audio
 437     if((w->wFormatTag == 0x01) && (w->nChannels == 2) && (w->nSamplesPerSec == 44100)) {
 438         unsigned char buf[16384]; // vlc uses 16384*4 (4 dts frames)
 439         unsigned int i;
 440         memset(buf, 0, sizeof(buf));
 441         stream_read(s, buf, sizeof(buf));
 442         for (i = 0; i < sizeof(buf) - 5; i += 2) {
 443             // DTS, 14 bit, LE
 444             if((buf[i] == 0xff) && (buf[i+1] == 0x1f) && (buf[i+2] == 0x00) &&
 445                (buf[i+3] == 0xe8) && ((buf[i+4] & 0xfe) == 0xf0) && (buf[i+5] == 0x07)) {
 446                 sh_audio->format = 0x2001;
 447                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, LE\n");
 448                 break;
 449             }
 450             // DTS, 14 bit, BE
 451             if((buf[i] == 0x1f) && (buf[i+1] == 0xff) && (buf[i+2] == 0xe8) &&
 452                (buf[i+3] == 0x00) && (buf[i+4] == 0x07) && ((buf[i+5] & 0xfe) == 0xf0)) {
 453                 sh_audio->format = 0x2001;
 454                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, BE\n");
 455                 break;
 456             }
 457             // DTS, 16 bit, BE
 458             if((buf[i] == 0x7f) && (buf[i+1] == 0xfe) && (buf[i+2] == 0x80) &&
 459                (buf[i+3] == 0x01)) {
 460                 sh_audio->format = 0x2001;
 461                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, BE\n");
 462                 break;
 463             }
 464             // DTS, 16 bit, LE
 465             if((buf[i] == 0xfe) && (buf[i+1] == 0x7f) && (buf[i+2] == 0x01) &&
 466                (buf[i+3] == 0x80)) {
 467                 sh_audio->format = 0x2001;
 468                 mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, LE\n");
 469                 break;
 470             }
 471         }
 472         if (sh_audio->format == 0x2001)
 473             mp_msg(MSGT_DEMUX,MSGL_DBG2,"[demux_audio] DTS sync offset = %u\n", i);
 474
 475     }
 476     stream_seek(s,demuxer->movi_start);
 477   } break;
 478   case fLaC:
 479             sh_audio->format = mmioFOURCC('f', 'L', 'a', 'C');
 480             demuxer->movi_start = stream_tell(s) - 4;
 481             demuxer->movi_end = s->end_pos;
 482             if (demuxer->movi_end > demuxer->movi_start) {
 483               // try to find out approx. bitrate
 484               int64_t size = demuxer->movi_end - demuxer->movi_start;
 485               int64_t num_samples = 0;
 486               int32_t srate = 0;
 487               stream_skip(s, 14);
 488               stream_read(s, (char *)&srate, 3);
 489               srate = be2me_32(srate) >> 12;
 490               stream_read(s, (char *)&num_samples, 5);
 491               num_samples = (be2me_64(num_samples) >> 24) & 0xfffffffffULL;
 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 //          get_flac_metadata (demuxer);
 498             break;
 499   }
 500
 501   priv = malloc(sizeof(da_priv_t));
 502   priv->frmt = frmt;
 503   priv->next_pts = 0;
 504   demuxer->priv = priv;
 505   demuxer->audio->id = 0;
 506   demuxer->audio->sh = sh_audio;
 507   sh_audio->ds = demuxer->audio;
 508   sh_audio->samplerate = sh_audio->audio.dwRate;
 509
 510   if(stream_tell(s) != demuxer->movi_start)
 511   {
 512     mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking from 0x%X to start pos 0x%X\n",
 513             (int)stream_tell(s), (int)demuxer->movi_start);
 514     stream_seek(s,demuxer->movi_start);
 515     if (stream_tell(s) != demuxer->movi_start) {
 516       mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking failed, now at 0x%X!\n",
 517               (int)stream_tell(s));
 518       if (next_frame_pos) {
 519         mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking to 0x%X instead\n",
 520                 (int)next_frame_pos);
 521         stream_seek(s, next_frame_pos);
 522       }
 523     }
 524   }
 525
 526   mp_msg(MSGT_DEMUX,MSGL_V,"demux_audio: audio data 0x%X - 0x%X  \n",(int)demuxer->movi_start,(int)demuxer->movi_end);
 527
 528   return DEMUXER_TYPE_AUDIO;
 529 }
 530
 531
 532 static int demux_audio_fill_buffer(demuxer_t *demux, demux_stream_t *ds) {
 533   int l;
 534   demux_packet_t* dp;
 535   sh_audio_t* sh_audio = ds->sh;
 536   da_priv_t* priv = demux->priv;
 537   double this_pts = priv->next_pts;
 538   stream_t* s = demux->stream;
 539
 540   if(s->eof)
 541     return 0;
 542
 543   switch(priv->frmt) {
 544   case MP3 :
 545     while(1) {
 546       uint8_t hdr[4];
 547       stream_read(s,hdr,4);
 548       if (s->eof)
 549         return 0;
 550       l = mp_decode_mp3_header(hdr);
 551       if(l < 0) {
 552         if (demux->movi_end && stream_tell(s) >= demux->movi_end)
 553           return 0; // might be ID3 tag, i.e. EOF
 554         stream_skip(s,-3);
 555       } else {
 556         dp = new_demux_packet(l);
 557         memcpy(dp->buffer,hdr,4);
 558         if (stream_read(s,dp->buffer + 4,l-4) != l-4)
 559         {
 560           free_demux_packet(dp);
 561           return 0;
 562         }
 563         priv->next_pts += sh_audio->audio.dwScale/(double)sh_audio->samplerate;
 564         break;
 565       }
 566     } break;
 567   case WAV : {
 568     unsigned align = sh_audio->wf->nBlockAlign;
 569     l = sh_audio->wf->nAvgBytesPerSec;
 570     if (l <= 0) l = 65536;
 571     if (demux->movi_end && l > demux->movi_end - stream_tell(s)) {
 572       // do not read beyond end, there might be junk after data chunk
 573       l = demux->movi_end - stream_tell(s);
 574       if (l <= 0) return 0;
 575     }
 576     if (align)
 577       l = (l + align - 1) / align * align;
 578     dp = new_demux_packet(l);
 579     l = stream_read(s,dp->buffer,l);
 580     priv->next_pts += l/(double)sh_audio->i_bps;
 581     break;
 582   }
 583   case fLaC: {
 584     l = 65535;
 585     dp = new_demux_packet(l);
 586     l = stream_read(s,dp->buffer,l);
 587     /* FLAC is not a constant-bitrate codec. These values will be wrong. */
 588     priv->next_pts += l/(double)sh_audio->i_bps;
 589     break;
 590   }
 591   default:
 592     mp_msg(MSGT_DEMUXER,MSGL_WARN,MSGTR_MPDEMUX_AUDIO_UnknownFormat,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   sh_audio_t* sh_audio;
 624   stream_t* s;
 625   int64_t base,pos;
 626   float len;
 627   da_priv_t* priv;
 628
 629   if(!(sh_audio = demuxer->audio->sh))
 630     return;
 631   s = demuxer->stream;
 632   priv = demuxer->priv;
 633
 634   if(priv->frmt == MP3 && hr_mp3_seek && !(flags & SEEK_FACTOR)) {
 635     len = (flags & SEEK_ABSOLUTE) ? rel_seek_secs - priv->next_pts : rel_seek_secs;
 636     if(len < 0) {
 637       stream_seek(s,demuxer->movi_start);
 638       len = priv->next_pts + len;
 639       priv->next_pts = 0;
 640     }
 641     if(len > 0)
 642       high_res_mp3_seek(demuxer,len);
 643     return;
 644   }
 645
 646   base = flags&SEEK_ABSOLUTE ? demuxer->movi_start : stream_tell(s);
 647   if(flags&SEEK_FACTOR)
 648     pos = base + ((demuxer->movi_end - demuxer->movi_start)*rel_seek_secs);
 649   else
 650     pos = base + (rel_seek_secs*sh_audio->i_bps);
 651
 652   if(demuxer->movi_end && pos >= demuxer->movi_end) {
 653      pos = demuxer->movi_end;
 654   } else if(pos < demuxer->movi_start)
 655     pos = demuxer->movi_start;
 656
 657   priv->next_pts = (pos-demuxer->movi_start)/(double)sh_audio->i_bps;
 658
 659   switch(priv->frmt) {
 660   case WAV:
 661     pos -= (pos - demuxer->movi_start) %
 662             (sh_audio->wf->nBlockAlign ? sh_audio->wf->nBlockAlign :
 663              (sh_audio->channels * sh_audio->samplesize));
 664     break;
 665   }
 666
 667   stream_seek(s,pos);
 668 }
 669
 670 static void demux_close_audio(demuxer_t* demuxer) {
 671   da_priv_t* priv = demuxer->priv;
 672
 673   if(!priv)
 674     return;
 675   free(priv);
 676 }
 677
 678 static int demux_audio_control(demuxer_t *demuxer,int cmd, void *arg){
 679     sh_audio_t *sh_audio=demuxer->audio->sh;
 680     int audio_length = sh_audio->i_bps ? demuxer->movi_end / sh_audio->i_bps : 0;
 681     da_priv_t* priv = demuxer->priv;
 682
 683     switch(cmd) {
 684         case DEMUXER_CTRL_GET_TIME_LENGTH:
 685             if (audio_length<=0) return DEMUXER_CTRL_DONTKNOW;
 686             *((double *)arg)=(double)audio_length;
 687             return DEMUXER_CTRL_GUESS;
 688
 689         case DEMUXER_CTRL_GET_PERCENT_POS:
 690             if (audio_length<=0)
 691                 return DEMUXER_CTRL_DONTKNOW;
 692             *((int *)arg)=(int)( (priv->next_pts*100)  / audio_length);
 693             return DEMUXER_CTRL_OK;
 694
 695         default:
 696             return DEMUXER_CTRL_NOTIMPL;
 697     }
 698 }
 699
 700
 701 const demuxer_desc_t demuxer_desc_audio = {
 702   "Audio demuxer",
 703   "audio",
 704   "Audio only",
 705   "?",
 706   "Audio only files",
 707   DEMUXER_TYPE_AUDIO,
 708   0, // unsafe autodetect
 709   demux_audio_open,
 710   demux_audio_fill_buffer,
 711   NULL,
 712   demux_close_audio,
 713   demux_audio_seek,
 714   demux_audio_control
 715 };