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 1.21 2003/10/23 21:28:11 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                 aout_DateSet( &p_sys->end_date, p_sys->pts );
 280             }
 281             p_sys->i_state = STATE_HEADER;
 282             break;
 283
 284         case STATE_HEADER:
 285             /* Get MPGA frame header (MPGA_HEADER_SIZE bytes) */
 286             if( block_PeekBytes( &p_sys->bytestream, p_header,
 287                                  MPGA_HEADER_SIZE ) != VLC_SUCCESS )
 288             {
 289                 /* Need more data */
 290                 return VLC_SUCCESS;
 291             }
 292
 293             /* Build frame header */
 294             i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
 295                        |p_header[3];
 296
 297             /* Check if frame is valid and get frame info */
 298             p_sys->i_frame_size = SyncInfo( i_header,
 299                                             &p_sys->i_channels,
 300                                             &p_sys->i_channels_conf,
 301                                             &p_sys->i_rate,
 302                                             &p_sys->i_bit_rate,
 303                                             &p_sys->i_frame_length,
 304                                             &p_sys->i_max_frame_size,
 305                                             &p_sys->i_layer );
 306
 307             if( p_sys->i_frame_size == -1 )
 308             {
 309                 msg_Dbg( p_dec, "emulated start code" );
 310                 block_SkipByte( &p_sys->bytestream );
 311                 p_sys->i_state = STATE_NOSYNC;
 312                 break;
 313             }
 314
 315             if( p_sys->i_bit_rate == 0 )
 316             {
 317                 /* Free birate, but 99% emulated startcode :( */
 318                 if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE )
 319                 {
 320                     msg_Dbg( p_dec, "free bitrate mode");
 321                 }
 322                 p_sys->i_frame_size = p_sys->i_free_frame_size;
 323             }
 324
 325             p_sys->i_state = STATE_NEXT_SYNC;
 326
 327         case STATE_NEXT_SYNC:
 328             /* TODO: If p_block == NULL, flush the buffer without checking the
 329              * next sync word */
 330
 331             /* Check if next expected frame contains the sync word */
 332             if( block_PeekOffsetBytes( &p_sys->bytestream,
 333                                        p_sys->i_frame_size, p_header,
 334                                        MAD_BUFFER_GUARD ) != VLC_SUCCESS )
 335             {
 336                 /* Need more data */
 337                 return VLC_SUCCESS;
 338             }
 339
 340             if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
 341             {
 342                 /* Startcode is fine, let's try the header as an extra check */
 343                 int i_next_frame_size;
 344                 unsigned int i_next_channels, i_next_channels_conf;
 345                 unsigned int i_next_rate, i_next_bit_rate;
 346                 unsigned int i_next_frame_length, i_next_max_frame_size;
 347                 unsigned int i_next_layer;
 348
 349                 /* Build frame header */
 350                 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
 351                            |p_header[3];
 352
 353                 i_next_frame_size = SyncInfo( i_header,
 354                                               &i_next_channels,
 355                                               &i_next_channels_conf,
 356                                               &i_next_rate,
 357                                               &i_next_bit_rate,
 358                                               &i_next_frame_length,
 359                                               &i_next_max_frame_size,
 360                                               &i_next_layer );
 361
 362                 if( i_next_frame_size == -1 )
 363                 {
 364                     msg_Dbg( p_dec, "emulated start code on next frame" );
 365                     block_SkipByte( &p_sys->bytestream );
 366                     p_sys->i_state = STATE_NOSYNC;
 367                     break;
 368                 }
 369
 370                 /* Free bitrate only */
 371                 if( p_sys->i_bit_rate == 0 )
 372                 {
 373                     if( i_next_bit_rate != 0 )
 374                     {
 375                         p_sys->i_frame_size++;
 376                         break;
 377                     }
 378
 379                     if( (unsigned int)p_sys->i_frame_size >
 380                         p_sys->i_max_frame_size )
 381                     {
 382                         msg_Dbg( p_dec, "frame too big %d > %d "
 383                                  "(emulated startcode ?)", p_sys->i_frame_size,
 384                                  p_sys->i_max_frame_size );
 385                         block_SkipByte( &p_sys->bytestream );
 386                         p_sys->i_state = STATE_NOSYNC;
 387                         p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
 388                         break;
 389                     }
 390                 }
 391
 392                 /* Check info is in sync with previous one */
 393                 if( i_next_channels_conf != p_sys->i_channels_conf ||
 394                     i_next_rate != p_sys->i_rate ||
 395                     i_next_layer != p_sys->i_layer ||
 396                     i_next_frame_length != p_sys->i_frame_length )
 397                 {
 398                     /* Free bitrate only */
 399                     if( p_sys->i_bit_rate == 0 )
 400                     {
 401                         p_sys->i_frame_size++;
 402                         break;
 403                     }
 404
 405                     msg_Dbg( p_dec, "parameters changed unexpectedly "
 406                              "(emulated startcode ?)" );
 407                     block_SkipByte( &p_sys->bytestream );
 408                     p_sys->i_state = STATE_NOSYNC;
 409                     break;
 410                 }
 411             }
 412             else
 413             {
 414                 /* Free bitrate only */
 415                 if( p_sys->i_bit_rate == 0 )
 416                 {
 417                     p_sys->i_frame_size++;
 418                     break;
 419                 }
 420
 421                 msg_Dbg( p_dec, "emulated startcode "
 422                          "(no startcode on following frame)" );
 423                 p_sys->i_state = STATE_NOSYNC;
 424                 block_SkipByte( &p_sys->bytestream );
 425                 break;
 426             }
 427
 428             if( GetOutBuffer( p_dec, &p_sys->p_out_buffer ) != VLC_SUCCESS )
 429             {
 430                 return VLC_EGENERIC;
 431             }
 432
 433             /* Free bitrate only */
 434             if( p_sys->i_bit_rate == 0 )
 435             {
 436                 p_sys->i_free_frame_size = p_sys->i_frame_size;
 437             }
 438
 439             p_sys->i_state = STATE_DATA;
 440
 441         case STATE_DATA:
 442             /* Copy the whole frame into the buffer */
 443             if( block_GetBytes( &p_sys->bytestream, p_sys->p_out_buffer,
 444                                 p_sys->i_frame_size ) != VLC_SUCCESS )
 445             {
 446                 /* Need more data */
 447                 return VLC_SUCCESS;
 448             }
 449
 450             p_sys->p_chain = block_BytestreamFlush( &p_sys->bytestream );
 451
 452             /* Get beginning of next frame for libmad */
 453             if( !p_sys->b_packetizer )
 454             {
 455                 memcpy( p_sys->p_out_buffer + p_sys->i_frame_size,
 456                         p_header, MAD_BUFFER_GUARD );
 457             }
 458
 459             SendOutBuffer( p_dec );
 460             p_sys->i_state = STATE_NOSYNC;
 461
 462             /* Make sure we don't reuse the same pts twice */
 463             if( p_sys->pts == p_sys->bytestream.p_block->i_pts )
 464                 p_sys->pts = p_sys->bytestream.p_block->i_pts = 0;
 465         }
 466     }
 467
 468     return VLC_SUCCESS;
 469 }
 470
 471 /*****************************************************************************
 472  * GetOutBuffer:
 473  *****************************************************************************/
 474 static int GetOutBuffer( decoder_t *p_dec, uint8_t **pp_out_buffer )
 475 {
 476     decoder_sys_t *p_sys = p_dec->p_sys;
 477     int i_ret;
 478
 479     if( p_sys->b_packetizer )
 480     {
 481         i_ret = GetSoutBuffer( p_dec, &p_sys->p_sout_buffer );
 482         *pp_out_buffer =
 483             p_sys->p_sout_buffer ? p_sys->p_sout_buffer->p_buffer : NULL;
 484     }
 485     else
 486     {
 487         i_ret = GetAoutBuffer( p_dec, &p_sys->p_aout_buffer );
 488         *pp_out_buffer =
 489             p_sys->p_aout_buffer ? p_sys->p_aout_buffer->p_buffer : NULL;
 490     }
 491
 492     return i_ret;
 493 }
 494
 495 /*****************************************************************************
 496  * GetAoutBuffer:
 497  *****************************************************************************/
 498 static int GetAoutBuffer( decoder_t *p_dec, aout_buffer_t **pp_buffer )
 499 {
 500     decoder_sys_t *p_sys = p_dec->p_sys;
 501
 502     if( p_sys->p_aout_input != NULL &&
 503         ( p_sys->aout_format.i_rate != p_sys->i_rate
 504         || p_sys->aout_format.i_original_channels != p_sys->i_channels_conf
 505         || p_sys->aout_format.i_bytes_per_frame !=
 506            p_sys->i_max_frame_size + MAD_BUFFER_GUARD
 507         || p_sys->aout_format.i_frame_length != p_sys->i_frame_length
 508         || p_sys->i_current_layer != p_sys->i_layer ) )
 509     {
 510         /* Parameters changed - this should not happen. */
 511         aout_DecDelete( p_sys->p_aout, p_sys->p_aout_input );
 512         p_sys->p_aout_input = NULL;
 513     }
 514
 515     /* Creating the audio input if not created yet. */
 516     if( p_sys->p_aout_input == NULL )
 517     {
 518         p_sys->i_current_layer = p_sys->i_layer;
 519         if( p_sys->i_layer == 3 )
 520         {
 521             p_sys->aout_format.i_format = VLC_FOURCC('m','p','g','3');
 522         }
 523         else
 524         {
 525             p_sys->aout_format.i_format = VLC_FOURCC('m','p','g','a');
 526         }
 527
 528         p_sys->aout_format.i_rate = p_sys->i_rate;
 529         p_sys->aout_format.i_original_channels = p_sys->i_channels_conf;
 530         p_sys->aout_format.i_physical_channels
 531             = p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 532         p_sys->aout_format.i_bytes_per_frame = p_sys->i_max_frame_size
 533             + MAD_BUFFER_GUARD;
 534         p_sys->aout_format.i_frame_length = p_sys->i_frame_length;
 535         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 536         aout_DateSet( &p_sys->end_date, p_sys->pts );
 537         p_sys->p_aout_input = aout_DecNew( p_dec,
 538                                            &p_sys->p_aout,
 539                                            &p_sys->aout_format );
 540         if( p_sys->p_aout_input == NULL )
 541         {
 542             *pp_buffer = NULL;
 543             return VLC_EGENERIC;
 544         }
 545     }
 546
 547     *pp_buffer = aout_DecNewBuffer( p_sys->p_aout, p_sys->p_aout_input,
 548                                     p_sys->i_frame_length );
 549     if( *pp_buffer == NULL )
 550     {
 551         return VLC_EGENERIC;
 552     }
 553
 554     (*pp_buffer)->start_date = aout_DateGet( &p_sys->end_date );
 555     (*pp_buffer)->end_date =
 556          aout_DateIncrement( &p_sys->end_date, p_sys->i_frame_length );
 557
 558     return VLC_SUCCESS;
 559 }
 560
 561 /*****************************************************************************
 562  * GetSoutBuffer:
 563  *****************************************************************************/
 564 static int GetSoutBuffer( decoder_t *p_dec, sout_buffer_t **pp_buffer )
 565 {
 566     decoder_sys_t *p_sys = p_dec->p_sys;
 567
 568     if( p_sys->p_sout_input != NULL &&
 569         ( p_sys->sout_format.i_sample_rate != (int)p_sys->i_rate
 570           || p_sys->sout_format.i_channels != (int)p_sys->i_channels ) )
 571     {
 572         /* Parameters changed - this should not happen. */
 573     }
 574
 575     /* Creating the sout input if not created yet. */
 576     if( p_sys->p_sout_input == NULL )
 577     {
 578         p_sys->sout_format.i_sample_rate = p_sys->i_rate;
 579         p_sys->sout_format.i_channels    = p_sys->i_channels;
 580         p_sys->sout_format.i_block_align = 0;
 581         p_sys->sout_format.i_bitrate     = p_sys->i_bit_rate;
 582         p_sys->sout_format.i_extra_data  = 0;
 583         p_sys->sout_format.p_extra_data  = NULL;
 584
 585         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 586         aout_DateSet( &p_sys->end_date, p_sys->pts );
 587
 588         p_sys->p_sout_input = sout_InputNew( p_dec, &p_sys->sout_format );
 589         if( p_sys->p_sout_input == NULL )
 590         {
 591             msg_Err( p_dec, "cannot add a new stream" );
 592             *pp_buffer = NULL;
 593             return VLC_EGENERIC;
 594         }
 595         msg_Info( p_dec, "MPGA channels:%d samplerate:%d bitrate:%d",
 596                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 597     }
 598
 599     *pp_buffer = sout_BufferNew( p_sys->p_sout_input->p_sout,
 600                                  p_sys->i_frame_size );
 601     if( *pp_buffer == NULL )
 602     {
 603         return VLC_EGENERIC;
 604     }
 605
 606     (*pp_buffer)->i_pts =
 607         (*pp_buffer)->i_dts = aout_DateGet( &p_sys->end_date );
 608
 609     (*pp_buffer)->i_length =
 610         aout_DateIncrement( &p_sys->end_date, p_sys->i_frame_length )
 611         - (*pp_buffer)->i_pts;
 612
 613     return VLC_SUCCESS;
 614 }
 615
 616 /*****************************************************************************
 617  * SendOutBuffer:
 618  *****************************************************************************/
 619 static int SendOutBuffer( decoder_t *p_dec )
 620 {
 621     decoder_sys_t *p_sys = p_dec->p_sys;
 622
 623     if( p_sys->b_packetizer )
 624     {
 625         sout_InputSendBuffer( p_sys->p_sout_input, p_sys->p_sout_buffer );
 626         p_sys->p_sout_buffer = NULL;
 627     }
 628     else
 629     {
 630         /* We have all we need, send the buffer to the aout core. */
 631         p_sys->p_aout_buffer->i_nb_bytes =
 632             p_sys->i_frame_size + MAD_BUFFER_GUARD;
 633         aout_DecPlay( p_sys->p_aout, p_sys->p_aout_input,
 634                       p_sys->p_aout_buffer );
 635         p_sys->p_aout_buffer = NULL;
 636     }
 637
 638     p_sys->p_out_buffer = NULL;
 639
 640     return VLC_SUCCESS;
 641 }
 642
 643 /*****************************************************************************
 644  * EndDecoder: clean up the decoder
 645  *****************************************************************************/
 646 static int EndDecoder( decoder_t *p_dec )
 647 {
 648     if( p_dec->p_sys->p_aout_input != NULL )
 649     {
 650         if( p_dec->p_sys->p_aout_buffer )
 651         {
 652             aout_DecDeleteBuffer( p_dec->p_sys->p_aout,
 653                                   p_dec->p_sys->p_aout_input,
 654                                   p_dec->p_sys->p_aout_buffer );
 655         }
 656
 657         aout_DecDelete( p_dec->p_sys->p_aout, p_dec->p_sys->p_aout_input );
 658     }
 659
 660     if( p_dec->p_sys->p_sout_input != NULL )
 661     {
 662         if( p_dec->p_sys->p_sout_buffer )
 663         {
 664             sout_BufferDelete( p_dec->p_sys->p_sout_input->p_sout,
 665                                p_dec->p_sys->p_sout_buffer );
 666         }
 667
 668         sout_InputDelete( p_dec->p_sys->p_sout_input );
 669     }
 670
 671     if( p_dec->p_sys->p_chain ) block_ChainRelease( p_dec->p_sys->p_chain );
 672
 673     free( p_dec->p_sys );
 674
 675     return VLC_SUCCESS;
 676 }
 677
 678 /*****************************************************************************
 679  * SyncInfo: parse MPEG audio sync info
 680  *****************************************************************************/
 681 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
 682                      unsigned int * pi_channels_conf,
 683                      unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
 684                      unsigned int * pi_frame_length,
 685                      unsigned int * pi_max_frame_size, unsigned int * pi_layer)
 686 {
 687     static const int ppi_bitrate[2][3][16] =
 688     {
 689         {
 690             /* v1 l1 */
 691             { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
 692               416, 448, 0},
 693             /* v1 l2 */
 694             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 160, 192, 224, 256,
 695               320, 384, 0},
 696             /* v1 l3 */
 697             { 0, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 224,
 698               256, 320, 0}
 699         },
 700
 701         {
 702             /* v2 l1 */
 703             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 144, 160, 176, 192,
 704               224, 256, 0},
 705             /* v2 l2 */
 706             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 707               144, 160, 0},
 708             /* v2 l3 */
 709             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 710               144, 160, 0}
 711         }
 712     };
 713
 714     static const int ppi_samplerate[2][4] = /* version 1 then 2 */
 715     {
 716         { 44100, 48000, 32000, 0 },
 717         { 22050, 24000, 16000, 0 }
 718     };
 719
 720     int i_version, i_mode, i_emphasis;
 721     vlc_bool_t b_padding, b_mpeg_2_5, b_crc;
 722     int i_frame_size = 0;
 723     int i_bitrate_index, i_samplerate_index;
 724     int i_max_bit_rate;
 725
 726     b_mpeg_2_5  = 1 - ((i_header & 0x100000) >> 20);
 727     i_version   = 1 - ((i_header & 0x80000) >> 19);
 728     *pi_layer   = 4 - ((i_header & 0x60000) >> 17);
 729     b_crc = !((i_header >> 16) & 0x01);
 730     i_bitrate_index = (i_header & 0xf000) >> 12;
 731     i_samplerate_index = (i_header & 0xc00) >> 10;
 732     b_padding   = (i_header & 0x200) >> 9;
 733     /* Extension */
 734     i_mode      = (i_header & 0xc0) >> 6;
 735     /* Modeext, copyright & original */
 736     i_emphasis  = i_header & 0x3;
 737
 738     if( *pi_layer != 4 &&
 739         i_bitrate_index < 0x0f &&
 740         i_samplerate_index != 0x03 &&
 741         i_emphasis != 0x02 )
 742     {
 743         switch ( i_mode )
 744         {
 745         case 0: /* stereo */
 746         case 1: /* joint stereo */
 747             *pi_channels = 2;
 748             *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 749             break;
 750         case 2: /* dual-mono */
 751             *pi_channels = 2;
 752             *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 753                                 | AOUT_CHAN_DUALMONO;
 754             break;
 755         case 3: /* mono */
 756             *pi_channels = 1;
 757             *pi_channels_conf = AOUT_CHAN_CENTER;
 758             break;
 759         }
 760         *pi_bit_rate = ppi_bitrate[i_version][*pi_layer-1][i_bitrate_index];
 761         i_max_bit_rate = ppi_bitrate[i_version][*pi_layer-1][14];
 762         *pi_sample_rate = ppi_samplerate[i_version][i_samplerate_index];
 763
 764         if ( b_mpeg_2_5 )
 765         {
 766             *pi_sample_rate >>= 1;
 767         }
 768
 769         switch( *pi_layer )
 770         {
 771         case 1:
 772             i_frame_size = ( 12000 * *pi_bit_rate / *pi_sample_rate +
 773                            b_padding ) * 4;
 774             *pi_max_frame_size = ( 12000 * i_max_bit_rate /
 775                                  *pi_sample_rate + 1 ) * 4;
 776             *pi_frame_length = 384;
 777             break;
 778
 779         case 2:
 780             i_frame_size = 144000 * *pi_bit_rate / *pi_sample_rate + b_padding;
 781             *pi_max_frame_size = 144000 * i_max_bit_rate / *pi_sample_rate + 1;
 782             *pi_frame_length = 1152;
 783             break;
 784
 785         case 3:
 786             i_frame_size = ( i_version ? 72000 : 144000 ) *
 787                            *pi_bit_rate / *pi_sample_rate + b_padding;
 788             *pi_max_frame_size = ( i_version ? 72000 : 144000 ) *
 789                                  i_max_bit_rate / *pi_sample_rate + 1;
 790             *pi_frame_length = i_version ? 576 : 1152;
 791             break;
 792
 793         default:
 794             break;
 795         }
 796     }
 797     else
 798     {
 799         return -1;
 800     }
 801
 802     return i_frame_size;
 803 }