git.sesse.net Git - vlc/blob - modules/codec/a52.c

   1 /*****************************************************************************
   2  * a52.c: parse A/52 audio sync info and packetize the stream
   3  *****************************************************************************
   4  * Copyright (C) 2001-2002 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Stéphane Borel <stef@via.ecp.fr>
   8  *          Christophe Massiot <massiot@via.ecp.fr>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <vlc_common.h>
  34 #include <vlc_plugin.h>
  35 #include <vlc_codec.h>
  36 #include <vlc_aout.h>
  37 #include <vlc_input.h>
  38 #include <vlc_block_helper.h>
  39 #include <vlc_bits.h>
  40
  41 /*****************************************************************************
  42  * Module descriptor
  43  *****************************************************************************/
  44 static int  OpenDecoder   ( vlc_object_t * );
  45 static int  OpenPacketizer( vlc_object_t * );
  46 static void CloseCommon   ( vlc_object_t * );
  47
  48 vlc_module_begin();
  49     set_description( N_("A/52 parser") );
  50     set_capability( "decoder", 100 );
  51     set_callbacks( OpenDecoder, CloseCommon );
  52     set_category( CAT_INPUT );
  53     set_subcategory( SUBCAT_INPUT_ACODEC );
  54
  55     add_submodule();
  56     set_description( N_("A/52 audio packetizer") );
  57     set_capability( "packetizer", 10 );
  58     set_callbacks( OpenPacketizer, CloseCommon );
  59 vlc_module_end();
  60
  61 /*****************************************************************************
  62  * decoder_sys_t : decoder descriptor
  63  *****************************************************************************/
  64
  65 #define A52_HEADER_SIZE 7
  66
  67 struct decoder_sys_t
  68 {
  69     /* Module mode */
  70     bool b_packetizer;
  71
  72     /*
  73      * Input properties
  74      */
  75     int i_state;
  76
  77     block_bytestream_t bytestream;
  78
  79     /*
  80      * Common properties
  81      */
  82     audio_date_t   end_date;
  83
  84     mtime_t i_pts;
  85     int i_frame_size, i_bit_rate;
  86     unsigned int i_rate, i_channels, i_channels_conf;
  87
  88     int i_input_rate;
  89 };
  90
  91 enum {
  92
  93     STATE_NOSYNC,
  94     STATE_SYNC,
  95     STATE_HEADER,
  96     STATE_NEXT_SYNC,
  97     STATE_GET_DATA,
  98     STATE_SEND_DATA
  99 };
 100
 101 /****************************************************************************
 102  * Local prototypes
 103  ****************************************************************************/
 104 static void *DecodeBlock  ( decoder_t *, block_t ** );
 105
 106 static int  SyncInfo      ( const uint8_t *, unsigned int *, unsigned int *,
 107                             unsigned int *, int * );
 108
 109 static uint8_t       *GetOutBuffer ( decoder_t *, void ** );
 110 static aout_buffer_t *GetAoutBuffer( decoder_t * );
 111 static block_t       *GetSoutBuffer( decoder_t * );
 112
 113 /*****************************************************************************
 114  * OpenCommon: probe the decoder/packetizer and return score
 115  *****************************************************************************/
 116 static int OpenCommon( vlc_object_t *p_this, bool b_packetizer )
 117 {
 118     decoder_t *p_dec = (decoder_t*)p_this;
 119     decoder_sys_t *p_sys;
 120     vlc_fourcc_t i_codec;
 121
 122     switch( p_dec->fmt_in.i_codec )
 123     {
 124     case VLC_FOURCC('a','5','2',' '):
 125     case VLC_FOURCC('a','5','2','b'):
 126         i_codec = VLC_FOURCC('a','5','2',' ');
 127         break;
 128     case VLC_FOURCC('e','a','c','3'):
 129         /* XXX ugly hack, a52 does not support eac3 so no eac3 pass-through
 130          * support */
 131         if( !b_packetizer )
 132             return VLC_EGENERIC;
 133         i_codec = VLC_FOURCC('e','a','c','3');
 134         break;
 135     default:
 136         return VLC_EGENERIC;
 137     }
 138
 139     /* Allocate the memory needed to store the decoder's structure */
 140     if( ( p_dec->p_sys = p_sys =
 141           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 142         return VLC_ENOMEM;
 143
 144     /* Misc init */
 145     p_sys->b_packetizer = b_packetizer;
 146     p_sys->i_state = STATE_NOSYNC;
 147     aout_DateSet( &p_sys->end_date, 0 );
 148
 149     p_sys->bytestream = block_BytestreamInit();
 150     p_sys->i_input_rate = INPUT_RATE_DEFAULT;
 151
 152     /* Set output properties */
 153     p_dec->fmt_out.i_cat = AUDIO_ES;
 154     p_dec->fmt_out.i_codec = i_codec;
 155     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 156
 157     /* Set callback */
 158     if( b_packetizer )
 159         p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 160             DecodeBlock;
 161     else
 162         p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 163             DecodeBlock;
 164     return VLC_SUCCESS;
 165 }
 166
 167 static int OpenDecoder( vlc_object_t *p_this )
 168 {
 169     return OpenCommon( p_this, false );
 170 }
 171
 172 static int OpenPacketizer( vlc_object_t *p_this )
 173 {
 174     return OpenCommon( p_this, true );
 175 }
 176
 177 /****************************************************************************
 178  * DecodeBlock: the whole thing
 179  ****************************************************************************
 180  * This function is called just after the thread is launched.
 181  ****************************************************************************/
 182 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 183 {
 184     decoder_sys_t *p_sys = p_dec->p_sys;
 185     uint8_t p_header[A52_HEADER_SIZE];
 186     uint8_t *p_buf;
 187     void *p_out_buffer;
 188
 189     if( !pp_block || !*pp_block ) return NULL;
 190
 191     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 192     {
 193         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 194         {
 195             p_sys->i_state = STATE_NOSYNC;
 196             block_BytestreamFlush( &p_sys->bytestream );
 197         }
 198 //        aout_DateSet( &p_sys->end_date, 0 );
 199         block_Release( *pp_block );
 200         return NULL;
 201     }
 202
 203     if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
 204     {
 205         /* We've just started the stream, wait for the first PTS. */
 206         block_Release( *pp_block );
 207         return NULL;
 208     }
 209
 210     if( (*pp_block)->i_rate > 0 )
 211         p_sys->i_input_rate = (*pp_block)->i_rate;
 212
 213     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 214
 215     while( 1 )
 216     {
 217         switch( p_sys->i_state )
 218         {
 219         case STATE_NOSYNC:
 220             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 221                    == VLC_SUCCESS )
 222             {
 223                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 224                 {
 225                     p_sys->i_state = STATE_SYNC;
 226                     break;
 227                 }
 228                 block_SkipByte( &p_sys->bytestream );
 229             }
 230             if( p_sys->i_state != STATE_SYNC )
 231             {
 232                 block_BytestreamFlush( &p_sys->bytestream );
 233
 234                 /* Need more data */
 235                 return NULL;
 236             }
 237
 238         case STATE_SYNC:
 239             /* New frame, set the Presentation Time Stamp */
 240             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 241             if( p_sys->i_pts != 0 &&
 242                 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
 243             {
 244                 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 245             }
 246             p_sys->i_state = STATE_HEADER;
 247
 248         case STATE_HEADER:
 249             /* Get A/52 frame header (A52_HEADER_SIZE bytes) */
 250             if( block_PeekBytes( &p_sys->bytestream, p_header,
 251                                  A52_HEADER_SIZE ) != VLC_SUCCESS )
 252             {
 253                 /* Need more data */
 254                 return NULL;
 255             }
 256
 257             /* Check if frame is valid and get frame info */
 258             p_sys->i_frame_size = SyncInfo( p_header,
 259                                             &p_sys->i_channels,
 260                                             &p_sys->i_channels_conf,
 261                                             &p_sys->i_rate,
 262                                             &p_sys->i_bit_rate );
 263             if( !p_sys->i_frame_size )
 264             {
 265                 msg_Dbg( p_dec, "emulated sync word" );
 266                 block_SkipByte( &p_sys->bytestream );
 267                 p_sys->i_state = STATE_NOSYNC;
 268                 break;
 269             }
 270             p_sys->i_state = STATE_NEXT_SYNC;
 271
 272         case STATE_NEXT_SYNC:
 273             /* TODO: If pp_block == NULL, flush the buffer without checking the
 274              * next sync word */
 275
 276             /* Check if next expected frame contains the sync word */
 277             if( block_PeekOffsetBytes( &p_sys->bytestream,
 278                                        p_sys->i_frame_size, p_header, 2 )
 279                 != VLC_SUCCESS )
 280             {
 281                 /* Need more data */
 282                 return NULL;
 283             }
 284
 285             if( p_sys->b_packetizer &&
 286                 p_header[0] == 0 && p_header[1] == 0 )
 287             {
 288                 /* A52 wav files and audio CD's use stuffing */
 289                 p_sys->i_state = STATE_GET_DATA;
 290                 break;
 291             }
 292
 293             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 294             {
 295                 msg_Dbg( p_dec, "emulated sync word "
 296                          "(no sync on following frame)" );
 297                 p_sys->i_state = STATE_NOSYNC;
 298                 block_SkipByte( &p_sys->bytestream );
 299                 break;
 300             }
 301             p_sys->i_state = STATE_SEND_DATA;
 302             break;
 303
 304         case STATE_GET_DATA:
 305             /* Make sure we have enough data.
 306              * (Not useful if we went through NEXT_SYNC) */
 307             if( block_WaitBytes( &p_sys->bytestream,
 308                                  p_sys->i_frame_size ) != VLC_SUCCESS )
 309             {
 310                 /* Need more data */
 311                 return NULL;
 312             }
 313             p_sys->i_state = STATE_SEND_DATA;
 314
 315         case STATE_SEND_DATA:
 316             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 317             {
 318                 //p_dec->b_error = true;
 319                 return NULL;
 320             }
 321
 322             /* Copy the whole frame into the buffer. When we reach this point
 323              * we already know we have enough data available. */
 324             block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
 325
 326             /* Make sure we don't reuse the same pts twice */
 327             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 328                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
 329
 330             /* So p_block doesn't get re-added several times */
 331             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 332
 333             p_sys->i_state = STATE_NOSYNC;
 334
 335             return p_out_buffer;
 336         }
 337     }
 338
 339     return NULL;
 340 }
 341
 342 /*****************************************************************************
 343  * CloseCommon: clean up the decoder
 344  *****************************************************************************/
 345 static void CloseCommon( vlc_object_t *p_this )
 346 {
 347     decoder_t *p_dec = (decoder_t*)p_this;
 348     decoder_sys_t *p_sys = p_dec->p_sys;
 349
 350     block_BytestreamRelease( &p_sys->bytestream );
 351
 352     free( p_sys );
 353 }
 354
 355 /*****************************************************************************
 356  * GetOutBuffer:
 357  *****************************************************************************/
 358 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
 359 {
 360     decoder_sys_t *p_sys = p_dec->p_sys;
 361     uint8_t *p_buf;
 362
 363     if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
 364     {
 365         msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 366                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 367
 368         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 369         aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 370     }
 371
 372     p_dec->fmt_out.audio.i_rate     = p_sys->i_rate;
 373     p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
 374     p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
 375     p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
 376
 377     p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
 378     p_dec->fmt_out.audio.i_physical_channels =
 379         p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 380
 381     p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
 382
 383     if( p_sys->b_packetizer )
 384     {
 385         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 386         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 387         *pp_out_buffer = p_sout_buffer;
 388     }
 389     else
 390     {
 391         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 392         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 393         *pp_out_buffer = p_aout_buffer;
 394     }
 395
 396     return p_buf;
 397 }
 398
 399 /*****************************************************************************
 400  * GetAoutBuffer:
 401  *****************************************************************************/
 402 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 403 {
 404     decoder_sys_t *p_sys = p_dec->p_sys;
 405     aout_buffer_t *p_buf;
 406
 407     p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB  );
 408     if( p_buf == NULL ) return NULL;
 409
 410     p_buf->start_date = aout_DateGet( &p_sys->end_date );
 411     p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 412                                           A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
 413
 414     return p_buf;
 415 }
 416
 417 /*****************************************************************************
 418  * GetSoutBuffer:
 419  *****************************************************************************/
 420 static block_t *GetSoutBuffer( decoder_t *p_dec )
 421 {
 422     decoder_sys_t *p_sys = p_dec->p_sys;
 423     block_t *p_block;
 424
 425     p_block = block_New( p_dec, p_sys->i_frame_size );
 426     if( p_block == NULL ) return NULL;
 427
 428     p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 429
 430     p_block->i_length =
 431         aout_DateIncrement( &p_sys->end_date,
 432                             A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
 433             p_block->i_pts;
 434
 435     return p_block;
 436 }
 437
 438 /* Tables */
 439 static const struct
 440 {
 441     unsigned int i_count;
 442     unsigned int i_configuration;
 443 } p_acmod[8] = {
 444     { 2, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_DUALMONO },   /* Dual-channel 1+1 */
 445     { 1, AOUT_CHAN_CENTER },                                        /* Mono 1/0 */
 446     { 2, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT },                        /* Stereo 2/0 */
 447     { 3, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER },     /* 3F 3/0 */
 448     { 3, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER }, /* 2F1R 2/1 */
 449     { 4, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
 450          AOUT_CHAN_REARCENTER },                                    /* 3F1R 3/1 */
 451     { 5, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 452          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT },                /* 2F2R 2/2 */
 453     { 6, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
 454          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT },                /* 3F2R 3/2 */
 455 };
 456
 457 /**
 458  * It parse AC3 sync info.
 459  *
 460  * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
 461  * since we don't want to oblige S/PDIF people to use liba52 just to get
 462  * their SyncInfo...
 463  */
 464 static int SyncInfoAC3( const uint8_t *p_buf,
 465                         unsigned int *pi_channels,
 466                         unsigned int *pi_channels_conf,
 467                         unsigned int *pi_sample_rate, int *pi_bit_rate )
 468 {
 469     static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
 470     static const int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
 471                                 128, 160, 192, 224, 256, 320, 384, 448,
 472                                 512, 576, 640 };
 473     static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
 474                                       0x04, 0x01, 0x04, 0x01 };
 475     int frmsizecod;
 476     int bitrate;
 477     int half;
 478     int acmod;
 479
 480     /* */
 481     half = halfrate[p_buf[5] >> 3];
 482
 483     /* acmod, dsurmod and lfeon */
 484     acmod = p_buf[6] >> 5;
 485     if ( (p_buf[6] & 0xf8) == 0x50 )
 486     {
 487         /* Dolby surround = stereo + Dolby */
 488         *pi_channels = 2;
 489         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 490                             | AOUT_CHAN_DOLBYSTEREO;
 491     }
 492     else
 493     {
 494         *pi_channels      = p_acmod[acmod].i_count;
 495         *pi_channels_conf = p_acmod[acmod].i_configuration;
 496     }
 497
 498     if ( p_buf[6] & lfeon[acmod] )
 499     {
 500         (*pi_channels)++;
 501         *pi_channels_conf |= AOUT_CHAN_LFE;
 502     }
 503
 504     frmsizecod = p_buf[4] & 63;
 505     if (frmsizecod >= 38)
 506         return 0;
 507     bitrate = rate [frmsizecod >> 1];
 508     *pi_bit_rate = (bitrate * 1000) >> half;
 509
 510     switch (p_buf[4] & 0xc0) {
 511     case 0:
 512         *pi_sample_rate = 48000 >> half;
 513         return 4 * bitrate;
 514     case 0x40:
 515         *pi_sample_rate = 44100 >> half;
 516         return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
 517     case 0x80:
 518         *pi_sample_rate = 32000 >> half;
 519         return 6 * bitrate;
 520     default:
 521         return 0;
 522     }
 523 }
 524
 525 /**
 526  * It parse E-AC3 sync info
 527  */
 528 static int SyncInfoEAC3( const uint8_t *p_buf,
 529                          unsigned int *pi_channels,
 530                          unsigned int *pi_channels_conf,
 531                          unsigned int *pi_sample_rate, int *pi_bit_rate )
 532 {
 533     static const int pi_samplerate[3] = { 48000, 44100, 32000 };
 534     bs_t s;
 535     int i_frame_size;
 536     int i_fscod, i_fscod2;
 537     int i_numblkscod;
 538     int i_acmod, i_lfeon;
 539     int i_bytes;
 540
 541
 542     bs_init( &s, (void*)p_buf, A52_HEADER_SIZE );
 543     bs_skip( &s, 16 +   /* start code */
 544                  2 +    /* stream type */
 545                  3 );   /* substream id */
 546     i_frame_size = bs_read( &s, 11 );
 547     if( i_frame_size < 2 )
 548         return 0;
 549     i_bytes = 2 * ( i_frame_size + 1 );
 550
 551     i_fscod = bs_read( &s, 2 );
 552     if( i_fscod == 0x03 )
 553     {
 554         i_fscod2 = bs_read( &s, 2 );
 555         if( i_fscod2 == 0X03 )
 556             return 0;
 557         *pi_sample_rate = pi_samplerate[i_fscod2] / 2;
 558         i_numblkscod = 6;
 559     }
 560     else
 561     {
 562         static const int pi_blocks[4] = { 1, 2, 3, 6 };
 563
 564         *pi_sample_rate = pi_samplerate[i_fscod];
 565         i_numblkscod = pi_blocks[bs_read( &s, 2 )];
 566     }
 567
 568     i_acmod = bs_read( &s, 3 );
 569     i_lfeon = bs_read1( &s );
 570
 571     *pi_channels      = p_acmod[i_acmod].i_count + i_lfeon;
 572     *pi_channels_conf = p_acmod[i_acmod].i_configuration | ( i_lfeon ? AOUT_CHAN_LFE : 0);
 573     *pi_bit_rate = 8 * i_bytes * (*pi_sample_rate) / (i_numblkscod * 256);
 574
 575     return i_bytes;
 576 }
 577
 578 static int SyncInfo( const uint8_t *p_buf,
 579                      unsigned int *pi_channels,
 580                      unsigned int *pi_channels_conf,
 581                      unsigned int *pi_sample_rate, int *pi_bit_rate )
 582 {
 583     int bsid;
 584
 585     /* Check synword */
 586     if( p_buf[0] != 0x0b || p_buf[1] != 0x77 )
 587         return 0;
 588
 589     /* Check bsid */
 590     bsid = p_buf[5] >> 3;
 591     if( bsid > 16 )
 592         return 0;
 593
 594     if( bsid <= 10 )
 595         return SyncInfoAC3( p_buf, pi_channels, pi_channels_conf,
 596                             pi_sample_rate, pi_bit_rate );
 597     else
 598         return SyncInfoEAC3( p_buf, pi_channels, pi_channels_conf,
 599                              pi_sample_rate, pi_bit_rate );
 600 }
 601