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