git.sesse.net Git - vlc/blob - modules/codec/mpeg_audio.c

   1 /*****************************************************************************
   2  * mpeg_audio.c: parse MPEG audio sync info and packetize the stream
   3  *****************************************************************************
   4  * Copyright (C) 2001-2003 VideoLAN
   5  * $Id: mpeg_audio.c,v 1.20 2003/10/23 20:51:20 gbazin Exp $
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Eric Petit <titer@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *          Gildas Bazin <gbazin@netcourrier.com>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #include <stdlib.h>                                      /* malloc(), free() */
  31 #include <string.h>                                              /* strdup() */
  32
  33 #include <vlc/vlc.h>
  34 #include <vlc/decoder.h>
  35 #include <vlc/input.h>
  36 #include <vlc/aout.h>
  37 #include <vlc/sout.h>
  38
  39 #include "vlc_block_helper.h"
  40
  41 /*****************************************************************************
  42  * decoder_sys_t : decoder descriptor
  43  *****************************************************************************/
  44 struct decoder_sys_t
  45 {
  46     /* Module mode */
  47     vlc_bool_t b_packetizer;
  48
  49     /*
  50      * Input properties
  51      */
  52     int        i_state;
  53
  54     block_t *p_chain;
  55     block_bytestream_t bytestream;
  56
  57     /*
  58      * Decoder output properties
  59      */
  60     aout_instance_t *     p_aout;                                  /* opaque */
  61     aout_input_t *        p_aout_input;                            /* opaque */
  62     audio_sample_format_t aout_format;
  63     aout_buffer_t *       p_aout_buffer; /* current aout buffer being filled */
  64
  65     /*
  66      * Packetizer output properties
  67      */
  68     sout_packetizer_input_t *p_sout_input;
  69     sout_format_t           sout_format;
  70     sout_buffer_t *         p_sout_buffer;            /* current sout buffer */
  71
  72     /*
  73      * Common properties
  74      */
  75     uint8_t               *p_out_buffer;                    /* output buffer */
  76     audio_date_t          end_date;
  77     unsigned int          i_current_layer;
  78
  79     mtime_t pts;
  80
  81     int i_frame_size, i_free_frame_size;
  82     unsigned int i_channels_conf, i_channels;
  83     unsigned int i_rate, i_max_frame_size, i_frame_length;
  84     unsigned int i_layer, i_bit_rate;
  85 };
  86
  87 enum {
  88
  89     STATE_NOSYNC,
  90     STATE_SYNC,
  91     STATE_HEADER,
  92     STATE_NEXT_SYNC,
  93     STATE_DATA
  94 };
  95
  96 /* This isn't the place to put mad-specific stuff. However, it makes the
  97  * mad plug-in's life much easier if we put 8 extra bytes at the end of the
  98  * buffer, because that way it doesn't have to copy the aout_buffer_t to a
  99  * bigger buffer. This has no implication on other plug-ins, and we only
 100  * lose 8 bytes per frame. --Meuuh */
 101 #define MAD_BUFFER_GUARD 8
 102 #define MPGA_HEADER_SIZE 4
 103
 104 /****************************************************************************
 105  * Local prototypes
 106  ****************************************************************************/
 107 static int OpenDecoder   ( vlc_object_t * );
 108 static int OpenPacketizer( vlc_object_t * );
 109
 110 static int InitDecoder   ( decoder_t * );
 111 static int RunDecoder    ( decoder_t *, block_t * );
 112 static int EndDecoder    ( decoder_t * );
 113
 114 static int GetOutBuffer ( decoder_t *, uint8_t ** );
 115 static int GetAoutBuffer( decoder_t *, aout_buffer_t ** );
 116 static int GetSoutBuffer( decoder_t *, sout_buffer_t ** );
 117 static int SendOutBuffer( decoder_t * );
 118
 119 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
 120                      unsigned int * pi_channels_conf,
 121                      unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
 122                      unsigned int * pi_frame_length,
 123                      unsigned int * pi_max_frame_size,
 124                      unsigned int * pi_layer );
 125
 126 /*****************************************************************************
 127  * Module descriptor
 128  *****************************************************************************/
 129 vlc_module_begin();
 130     set_description( _("MPEG audio layer I/II/III parser") );
 131     set_capability( "decoder", 100 );
 132     set_callbacks( OpenDecoder, NULL );
 133
 134     add_submodule();
 135     set_description( _("MPEG audio layer I/II/III packetizer") );
 136     set_capability( "packetizer", 10 );
 137     set_callbacks( OpenPacketizer, NULL );
 138 vlc_module_end();
 139
 140 /*****************************************************************************
 141  * OpenDecoder: probe the decoder and return score
 142  *****************************************************************************/
 143 static int OpenDecoder( vlc_object_t *p_this )
 144 {
 145     decoder_t *p_dec = (decoder_t*)p_this;
 146
 147     if( p_dec->p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', 'a') )
 148     {
 149         return VLC_EGENERIC;
 150     }
 151
 152     p_dec->pf_init = InitDecoder;
 153     p_dec->pf_decode = RunDecoder;
 154     p_dec->pf_end = EndDecoder;
 155
 156     /* Allocate the memory needed to store the decoder's structure */
 157     if( ( p_dec->p_sys =
 158           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 159     {
 160         msg_Err( p_dec, "out of memory" );
 161         return VLC_EGENERIC;
 162     }
 163     p_dec->p_sys->b_packetizer = VLC_FALSE;
 164
 165     return VLC_SUCCESS;
 166 }
 167
 168 static int OpenPacketizer( vlc_object_t *p_this )
 169 {
 170     decoder_t *p_dec = (decoder_t*)p_this;
 171
 172     int i_ret = OpenDecoder( p_this );
 173
 174     if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = VLC_TRUE;
 175
 176     return i_ret;
 177 }
 178
 179 /*****************************************************************************
 180  * InitDecoder: Initalize the decoder
 181  *****************************************************************************/
 182 static int InitDecoder( decoder_t *p_dec )
 183 {
 184     p_dec->p_sys->i_state = STATE_NOSYNC;
 185
 186     p_dec->p_sys->p_out_buffer = NULL;
 187     aout_DateSet( &p_dec->p_sys->end_date, 0 );
 188
 189     p_dec->p_sys->p_aout = NULL;
 190     p_dec->p_sys->p_aout_input = NULL;
 191     p_dec->p_sys->p_aout_buffer = NULL;
 192     p_dec->p_sys->aout_format.i_format = VLC_FOURCC('m','p','g','a');
 193
 194     p_dec->p_sys->p_sout_input = NULL;
 195     p_dec->p_sys->p_sout_buffer = NULL;
 196     p_dec->p_sys->sout_format.i_cat = AUDIO_ES;
 197     p_dec->p_sys->sout_format.i_fourcc = VLC_FOURCC('m','p','g','a');
 198
 199     /* Start with the minimum size for a free bitrate frame */
 200     p_dec->p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
 201
 202     p_dec->p_sys->p_chain = NULL;
 203
 204     return VLC_SUCCESS;
 205 }
 206
 207 /****************************************************************************
 208  * RunDecoder: the whole thing
 209  ****************************************************************************
 210  * This function is called just after the thread is launched.
 211  ****************************************************************************/
 212 static int RunDecoder( decoder_t *p_dec, block_t *p_block )
 213 {
 214     decoder_sys_t *p_sys = p_dec->p_sys;
 215     uint8_t p_header[MAD_BUFFER_GUARD];
 216     uint32_t i_header;
 217
 218     if( !aout_DateGet( &p_sys->end_date ) && !p_block->i_pts )
 219     {
 220         /* We've just started the stream, wait for the first PTS. */
 221         block_Release( p_block );
 222         return VLC_SUCCESS;
 223     }
 224
 225     if( p_block->b_discontinuity )
 226     {
 227         p_sys->i_state = STATE_SYNC;
 228     }
 229
 230     if( p_sys->p_chain )
 231     {
 232         block_ChainAppend( &p_sys->p_chain, p_block );
 233     }
 234     else
 235     {
 236         block_ChainAppend( &p_sys->p_chain, p_block );
 237         p_sys->bytestream = block_BytestreamInit( p_dec, p_sys->p_chain, 0 );
 238     }
 239
 240     while( 1 )
 241     {
 242         switch( p_sys->i_state )
 243         {
 244
 245         case STATE_NOSYNC:
 246             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 247                    == VLC_SUCCESS )
 248             {
 249                 /* Look for sync word - should be 0xffe */
 250                 if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
 251                 {
 252                     p_sys->i_state = STATE_SYNC;
 253                     break;
 254                 }
 255                 block_SkipByte( &p_sys->bytestream );
 256             }
 257             if( p_sys->i_state != STATE_SYNC )
 258             {
 259                 if( block_PeekByte( &p_sys->bytestream, p_header )
 260                     == VLC_SUCCESS && p_header[0] == 0xff )
 261                 {
 262                     /* Start of a sync word, need more data */
 263                     return VLC_SUCCESS;
 264                 }
 265
 266                 block_ChainRelease( p_sys->p_chain );
 267                 p_sys->p_chain = NULL;
 268
 269                 /* Need more data */
 270                 return VLC_SUCCESS;
 271             }
 272
 273         case STATE_SYNC:
 274             /* New frame, set the Presentation Time Stamp */
 275             p_sys->pts = p_sys->bytestream.p_block->i_pts;
 276             if( p_sys->pts != 0 &&
 277                 p_sys->pts != aout_DateGet( &p_sys->end_date ) )
 278             {
 279               msg_Err( p_dec, "set PTS: %lli old: %lli", p_sys->pts,
 280                        aout_DateGet( &p_sys->end_date ) );
 281                 aout_DateSet( &p_sys->end_date, p_sys->pts );
 282             }
 283             p_sys->i_state = STATE_HEADER;
 284             break;
 285
 286         case STATE_HEADER:
 287             /* Get MPGA frame header (MPGA_HEADER_SIZE bytes) */
 288             if( block_PeekBytes( &p_sys->bytestream, p_header,
 289                                  MPGA_HEADER_SIZE ) != VLC_SUCCESS )
 290             {
 291                 /* Need more data */
 292                 return VLC_SUCCESS;
 293             }
 294
 295             /* Build frame header */
 296             i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
 297                        |p_header[3];
 298
 299             /* Check if frame is valid and get frame info */
 300             p_sys->i_frame_size = SyncInfo( i_header,
 301                                             &p_sys->i_channels,
 302                                             &p_sys->i_channels_conf,
 303                                             &p_sys->i_rate,
 304                                             &p_sys->i_bit_rate,
 305                                             &p_sys->i_frame_length,
 306                                             &p_sys->i_max_frame_size,
 307                                             &p_sys->i_layer );
 308
 309             if( p_sys->i_frame_size == -1 )
 310             {
 311                 msg_Dbg( p_dec, "emulated start code" );
 312                 block_SkipByte( &p_sys->bytestream );
 313                 p_sys->i_state = STATE_NOSYNC;
 314                 break;
 315             }
 316
 317             if( p_sys->i_bit_rate == 0 )
 318             {
 319                 /* Free birate, but 99% emulated startcode :( */
 320                 if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE )
 321                 {
 322                     msg_Dbg( p_dec, "free bitrate mode");
 323                 }
 324                 p_sys->i_frame_size = p_sys->i_free_frame_size;
 325             }
 326
 327             p_sys->i_state = STATE_NEXT_SYNC;
 328
 329         case STATE_NEXT_SYNC:
 330             /* TODO: If p_block == NULL, flush the buffer without checking the
 331              * next sync word */
 332
 333             /* Check if next expected frame contains the sync word */
 334             if( block_PeekOffsetBytes( &p_sys->bytestream,
 335                                        p_sys->i_frame_size, p_header,
 336                                        MAD_BUFFER_GUARD ) != VLC_SUCCESS )
 337             {
 338                 /* Need more data */
 339                 return VLC_SUCCESS;
 340             }
 341
 342             if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
 343             {
 344                 /* Startcode is fine, let's try the header as an extra check */
 345                 int i_next_frame_size;
 346                 unsigned int i_next_channels, i_next_channels_conf;
 347                 unsigned int i_next_rate, i_next_bit_rate;
 348                 unsigned int i_next_frame_length, i_next_max_frame_size;
 349                 unsigned int i_next_layer;
 350
 351                 /* Build frame header */
 352                 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
 353                            |p_header[3];
 354
 355                 i_next_frame_size = SyncInfo( i_header,
 356                                               &i_next_channels,
 357                                               &i_next_channels_conf,
 358                                               &i_next_rate,
 359                                               &i_next_bit_rate,
 360                                               &i_next_frame_length,
 361                                               &i_next_max_frame_size,
 362                                               &i_next_layer );
 363
 364                 if( i_next_frame_size == -1 )
 365                 {
 366                     msg_Dbg( p_dec, "emulated start code on next frame" );
 367                     block_SkipByte( &p_sys->bytestream );
 368                     p_sys->i_state = STATE_NOSYNC;
 369                     break;
 370                 }
 371
 372                 /* Free bitrate only */
 373                 if( p_sys->i_bit_rate == 0 )
 374                 {
 375                     if( i_next_bit_rate != 0 )
 376                     {
 377                         p_sys->i_frame_size++;
 378                         break;
 379                     }
 380
 381                     if( (unsigned int)p_sys->i_frame_size >
 382                         p_sys->i_max_frame_size )
 383                     {
 384                         msg_Dbg( p_dec, "frame too big %d > %d "
 385                                  "(emulated startcode ?)", p_sys->i_frame_size,
 386                                  p_sys->i_max_frame_size );
 387                         block_SkipByte( &p_sys->bytestream );
 388                         p_sys->i_state = STATE_NOSYNC;
 389                         p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
 390                         break;
 391                     }
 392                 }
 393
 394                 /* Check info is in sync with previous one */
 395                 if( i_next_channels_conf != p_sys->i_channels_conf ||
 396                     i_next_rate != p_sys->i_rate ||
 397                     i_next_layer != p_sys->i_layer ||
 398                     i_next_frame_length != p_sys->i_frame_length )
 399                 {
 400                     /* Free bitrate only */
 401                     if( p_sys->i_bit_rate == 0 )
 402                     {
 403                         p_sys->i_frame_size++;
 404                         break;
 405                     }
 406
 407                     msg_Dbg( p_dec, "parameters changed unexpectedly "
 408                              "(emulated startcode ?)" );
 409                     block_SkipByte( &p_sys->bytestream );
 410                     p_sys->i_state = STATE_NOSYNC;
 411                     break;
 412                 }
 413             }
 414             else
 415             {
 416                 /* Free bitrate only */
 417                 if( p_sys->i_bit_rate == 0 )
 418                 {
 419                     p_sys->i_frame_size++;
 420                     break;
 421                 }
 422
 423                 msg_Dbg( p_dec, "emulated startcode "
 424                          "(no startcode on following frame)" );
 425                 p_sys->i_state = STATE_NOSYNC;
 426                 block_SkipByte( &p_sys->bytestream );
 427                 break;
 428             }
 429
 430             if( GetOutBuffer( p_dec, &p_sys->p_out_buffer ) != VLC_SUCCESS )
 431             {
 432                 return VLC_EGENERIC;
 433             }
 434
 435             /* Free bitrate only */
 436             if( p_sys->i_bit_rate == 0 )
 437             {
 438                 p_sys->i_free_frame_size = p_sys->i_frame_size;
 439             }
 440
 441             p_sys->i_state = STATE_DATA;
 442
 443         case STATE_DATA:
 444             /* Copy the whole frame into the buffer */
 445             if( block_GetBytes( &p_sys->bytestream, p_sys->p_out_buffer,
 446                                 p_sys->i_frame_size ) != VLC_SUCCESS )
 447             {
 448                 /* Need more data */
 449                 return VLC_SUCCESS;
 450             }
 451
 452             p_sys->p_chain = block_BytestreamFlush( &p_sys->bytestream );
 453
 454             /* Get beginning of next frame for libmad */
 455             if( !p_sys->b_packetizer )
 456             {
 457                 memcpy( p_sys->p_out_buffer + p_sys->i_frame_size,
 458                         p_header, MAD_BUFFER_GUARD );
 459             }
 460
 461             SendOutBuffer( p_dec );
 462             p_sys->i_state = STATE_NOSYNC;
 463
 464             /* Make sure we don't reuse the same pts twice */
 465             if( p_sys->pts == p_sys->bytestream.p_block->i_pts )
 466                 p_sys->pts = p_sys->bytestream.p_block->i_pts = 0;
 467         }
 468     }
 469
 470     return VLC_SUCCESS;
 471 }
 472
 473 /*****************************************************************************
 474  * GetOutBuffer:
 475  *****************************************************************************/
 476 static int GetOutBuffer( decoder_t *p_dec, uint8_t **pp_out_buffer )
 477 {
 478     decoder_sys_t *p_sys = p_dec->p_sys;
 479     int i_ret;
 480
 481     if( p_sys->b_packetizer )
 482     {
 483         i_ret = GetSoutBuffer( p_dec, &p_sys->p_sout_buffer );
 484         *pp_out_buffer =
 485             p_sys->p_sout_buffer ? p_sys->p_sout_buffer->p_buffer : NULL;
 486     }
 487     else
 488     {
 489         i_ret = GetAoutBuffer( p_dec, &p_sys->p_aout_buffer );
 490         *pp_out_buffer =
 491             p_sys->p_aout_buffer ? p_sys->p_aout_buffer->p_buffer : NULL;
 492     }
 493
 494     return i_ret;
 495 }
 496
 497 /*****************************************************************************
 498  * GetAoutBuffer:
 499  *****************************************************************************/
 500 static int GetAoutBuffer( decoder_t *p_dec, aout_buffer_t **pp_buffer )
 501 {
 502     decoder_sys_t *p_sys = p_dec->p_sys;
 503
 504     if( p_sys->p_aout_input != NULL &&
 505         ( p_sys->aout_format.i_rate != p_sys->i_rate
 506         || p_sys->aout_format.i_original_channels != p_sys->i_channels_conf
 507         || p_sys->aout_format.i_bytes_per_frame !=
 508            p_sys->i_max_frame_size + MAD_BUFFER_GUARD
 509         || p_sys->aout_format.i_frame_length != p_sys->i_frame_length
 510         || p_sys->i_current_layer != p_sys->i_layer ) )
 511     {
 512         /* Parameters changed - this should not happen. */
 513         aout_DecDelete( p_sys->p_aout, p_sys->p_aout_input );
 514         p_sys->p_aout_input = NULL;
 515     }
 516
 517     /* Creating the audio input if not created yet. */
 518     if( p_sys->p_aout_input == NULL )
 519     {
 520         p_sys->i_current_layer = p_sys->i_layer;
 521         if( p_sys->i_layer == 3 )
 522         {
 523             p_sys->aout_format.i_format = VLC_FOURCC('m','p','g','3');
 524         }
 525         else
 526         {
 527             p_sys->aout_format.i_format = VLC_FOURCC('m','p','g','a');
 528         }
 529
 530         p_sys->aout_format.i_rate = p_sys->i_rate;
 531         p_sys->aout_format.i_original_channels = p_sys->i_channels_conf;
 532         p_sys->aout_format.i_physical_channels
 533             = p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 534         p_sys->aout_format.i_bytes_per_frame = p_sys->i_max_frame_size
 535             + MAD_BUFFER_GUARD;
 536         p_sys->aout_format.i_frame_length = p_sys->i_frame_length;
 537         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 538         aout_DateSet( &p_sys->end_date, p_sys->pts );
 539         p_sys->p_aout_input = aout_DecNew( p_dec,
 540                                            &p_sys->p_aout,
 541                                            &p_sys->aout_format );
 542         if( p_sys->p_aout_input == NULL )
 543         {
 544             *pp_buffer = NULL;
 545             return VLC_EGENERIC;
 546         }
 547     }
 548
 549     *pp_buffer = aout_DecNewBuffer( p_sys->p_aout, p_sys->p_aout_input,
 550                                     p_sys->i_frame_length );
 551     if( *pp_buffer == NULL )
 552     {
 553         return VLC_EGENERIC;
 554     }
 555
 556     (*pp_buffer)->start_date = aout_DateGet( &p_sys->end_date );
 557     (*pp_buffer)->end_date =
 558          aout_DateIncrement( &p_sys->end_date, p_sys->i_frame_length );
 559
 560     return VLC_SUCCESS;
 561 }
 562
 563 /*****************************************************************************
 564  * GetSoutBuffer:
 565  *****************************************************************************/
 566 static int GetSoutBuffer( decoder_t *p_dec, sout_buffer_t **pp_buffer )
 567 {
 568     decoder_sys_t *p_sys = p_dec->p_sys;
 569
 570     if( p_sys->p_sout_input != NULL &&
 571         ( p_sys->sout_format.i_sample_rate != (int)p_sys->i_rate
 572           || p_sys->sout_format.i_channels != (int)p_sys->i_channels ) )
 573     {
 574         /* Parameters changed - this should not happen. */
 575     }
 576
 577     /* Creating the sout input if not created yet. */
 578     if( p_sys->p_sout_input == NULL )
 579     {
 580         p_sys->sout_format.i_sample_rate = p_sys->i_rate;
 581         p_sys->sout_format.i_channels    = p_sys->i_channels;
 582         p_sys->sout_format.i_block_align = 0;
 583         p_sys->sout_format.i_bitrate     = p_sys->i_bit_rate;
 584         p_sys->sout_format.i_extra_data  = 0;
 585         p_sys->sout_format.p_extra_data  = NULL;
 586
 587         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 588         aout_DateSet( &p_sys->end_date, p_sys->pts );
 589
 590         p_sys->p_sout_input = sout_InputNew( p_dec, &p_sys->sout_format );
 591         if( p_sys->p_sout_input == NULL )
 592         {
 593             msg_Err( p_dec, "cannot add a new stream" );
 594             *pp_buffer = NULL;
 595             return VLC_EGENERIC;
 596         }
 597         msg_Info( p_dec, "MPGA channels:%d samplerate:%d bitrate:%d",
 598                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 599     }
 600
 601     *pp_buffer = sout_BufferNew( p_sys->p_sout_input->p_sout,
 602                                  p_sys->i_frame_size );
 603     if( *pp_buffer == NULL )
 604     {
 605         return VLC_EGENERIC;
 606     }
 607
 608     (*pp_buffer)->i_pts =
 609         (*pp_buffer)->i_dts = aout_DateGet( &p_sys->end_date );
 610
 611     (*pp_buffer)->i_length =
 612         aout_DateIncrement( &p_sys->end_date, p_sys->i_frame_length )
 613         - (*pp_buffer)->i_pts;
 614
 615     return VLC_SUCCESS;
 616 }
 617
 618 /*****************************************************************************
 619  * SendOutBuffer:
 620  *****************************************************************************/
 621 static int SendOutBuffer( decoder_t *p_dec )
 622 {
 623     decoder_sys_t *p_sys = p_dec->p_sys;
 624
 625     if( p_sys->b_packetizer )
 626     {
 627         sout_InputSendBuffer( p_sys->p_sout_input, p_sys->p_sout_buffer );
 628         p_sys->p_sout_buffer = NULL;
 629     }
 630     else
 631     {
 632         /* We have all we need, send the buffer to the aout core. */
 633         p_sys->p_aout_buffer->i_nb_bytes =
 634             p_sys->i_frame_size + MAD_BUFFER_GUARD;
 635         aout_DecPlay( p_sys->p_aout, p_sys->p_aout_input,
 636                       p_sys->p_aout_buffer );
 637         p_sys->p_aout_buffer = NULL;
 638     }
 639
 640     p_sys->p_out_buffer = NULL;
 641
 642     return VLC_SUCCESS;
 643 }
 644
 645 /*****************************************************************************
 646  * EndDecoder: clean up the decoder
 647  *****************************************************************************/
 648 static int EndDecoder( decoder_t *p_dec )
 649 {
 650     if( p_dec->p_sys->p_aout_input != NULL )
 651     {
 652         if( p_dec->p_sys->p_aout_buffer )
 653         {
 654             aout_DecDeleteBuffer( p_dec->p_sys->p_aout,
 655                                   p_dec->p_sys->p_aout_input,
 656                                   p_dec->p_sys->p_aout_buffer );
 657         }
 658
 659         aout_DecDelete( p_dec->p_sys->p_aout, p_dec->p_sys->p_aout_input );
 660     }
 661
 662     if( p_dec->p_sys->p_sout_input != NULL )
 663     {
 664         if( p_dec->p_sys->p_sout_buffer )
 665         {
 666             sout_BufferDelete( p_dec->p_sys->p_sout_input->p_sout,
 667                                p_dec->p_sys->p_sout_buffer );
 668         }
 669
 670         sout_InputDelete( p_dec->p_sys->p_sout_input );
 671     }
 672
 673     if( p_dec->p_sys->p_chain ) block_ChainRelease( p_dec->p_sys->p_chain );
 674
 675     free( p_dec->p_sys );
 676
 677     return VLC_SUCCESS;
 678 }
 679
 680 /*****************************************************************************
 681  * SyncInfo: parse MPEG audio sync info
 682  *****************************************************************************/
 683 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
 684                      unsigned int * pi_channels_conf,
 685                      unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
 686                      unsigned int * pi_frame_length,
 687                      unsigned int * pi_max_frame_size, unsigned int * pi_layer)
 688 {
 689     static const int ppi_bitrate[2][3][16] =
 690     {
 691         {
 692             /* v1 l1 */
 693             { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
 694               416, 448, 0},
 695             /* v1 l2 */
 696             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 160, 192, 224, 256,
 697               320, 384, 0},
 698             /* v1 l3 */
 699             { 0, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 224,
 700               256, 320, 0}
 701         },
 702
 703         {
 704             /* v2 l1 */
 705             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 144, 160, 176, 192,
 706               224, 256, 0},
 707             /* v2 l2 */
 708             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 709               144, 160, 0},
 710             /* v2 l3 */
 711             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 712               144, 160, 0}
 713         }
 714     };
 715
 716     static const int ppi_samplerate[2][4] = /* version 1 then 2 */
 717     {
 718         { 44100, 48000, 32000, 0 },
 719         { 22050, 24000, 16000, 0 }
 720     };
 721
 722     int i_version, i_mode, i_emphasis;
 723     vlc_bool_t b_padding, b_mpeg_2_5, b_crc;
 724     int i_frame_size = 0;
 725     int i_bitrate_index, i_samplerate_index;
 726     int i_max_bit_rate;
 727
 728     b_mpeg_2_5  = 1 - ((i_header & 0x100000) >> 20);
 729     i_version   = 1 - ((i_header & 0x80000) >> 19);
 730     *pi_layer   = 4 - ((i_header & 0x60000) >> 17);
 731     b_crc = !((i_header >> 16) & 0x01);
 732     i_bitrate_index = (i_header & 0xf000) >> 12;
 733     i_samplerate_index = (i_header & 0xc00) >> 10;
 734     b_padding   = (i_header & 0x200) >> 9;
 735     /* Extension */
 736     i_mode      = (i_header & 0xc0) >> 6;
 737     /* Modeext, copyright & original */
 738     i_emphasis  = i_header & 0x3;
 739
 740     if( *pi_layer != 4 &&
 741         i_bitrate_index < 0x0f &&
 742         i_samplerate_index != 0x03 &&
 743         i_emphasis != 0x02 )
 744     {
 745         switch ( i_mode )
 746         {
 747         case 0: /* stereo */
 748         case 1: /* joint stereo */
 749             *pi_channels = 2;
 750             *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 751             break;
 752         case 2: /* dual-mono */
 753             *pi_channels = 2;
 754             *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 755                                 | AOUT_CHAN_DUALMONO;
 756             break;
 757         case 3: /* mono */
 758             *pi_channels = 1;
 759             *pi_channels_conf = AOUT_CHAN_CENTER;
 760             break;
 761         }
 762         *pi_bit_rate = ppi_bitrate[i_version][*pi_layer-1][i_bitrate_index];
 763         i_max_bit_rate = ppi_bitrate[i_version][*pi_layer-1][14];
 764         *pi_sample_rate = ppi_samplerate[i_version][i_samplerate_index];
 765
 766         if ( b_mpeg_2_5 )
 767         {
 768             *pi_sample_rate >>= 1;
 769         }
 770
 771         switch( *pi_layer )
 772         {
 773         case 1:
 774             i_frame_size = ( 12000 * *pi_bit_rate / *pi_sample_rate +
 775                            b_padding ) * 4;
 776             *pi_max_frame_size = ( 12000 * i_max_bit_rate /
 777                                  *pi_sample_rate + 1 ) * 4;
 778             *pi_frame_length = 384;
 779             break;
 780
 781         case 2:
 782             i_frame_size = 144000 * *pi_bit_rate / *pi_sample_rate + b_padding;
 783             *pi_max_frame_size = 144000 * i_max_bit_rate / *pi_sample_rate + 1;
 784             *pi_frame_length = 1152;
 785             break;
 786
 787         case 3:
 788             i_frame_size = ( i_version ? 72000 : 144000 ) *
 789                            *pi_bit_rate / *pi_sample_rate + b_padding;
 790             *pi_max_frame_size = ( i_version ? 72000 : 144000 ) *
 791                                  i_max_bit_rate / *pi_sample_rate + 1;
 792             *pi_frame_length = i_version ? 576 : 1152;
 793             break;
 794
 795         default:
 796             break;
 797         }
 798     }
 799     else
 800     {
 801         return -1;
 802     }
 803
 804     return i_frame_size;
 805 }