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/vlc.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
  40 #define A52_HEADER_SIZE 7
  41
  42 /*****************************************************************************
  43  * decoder_sys_t : decoder descriptor
  44  *****************************************************************************/
  45 struct decoder_sys_t
  46 {
  47     /* Module mode */
  48     bool b_packetizer;
  49
  50     /*
  51      * Input properties
  52      */
  53     int i_state;
  54
  55     block_bytestream_t bytestream;
  56
  57     /*
  58      * Common properties
  59      */
  60     audio_date_t   end_date;
  61
  62     mtime_t i_pts;
  63     int i_frame_size, i_bit_rate;
  64     unsigned int i_rate, i_channels, i_channels_conf;
  65
  66     int i_input_rate;
  67 };
  68
  69 enum {
  70
  71     STATE_NOSYNC,
  72     STATE_SYNC,
  73     STATE_HEADER,
  74     STATE_NEXT_SYNC,
  75     STATE_GET_DATA,
  76     STATE_SEND_DATA
  77 };
  78
  79 /****************************************************************************
  80  * Local prototypes
  81  ****************************************************************************/
  82 static int  OpenDecoder   ( vlc_object_t * );
  83 static int  OpenPacketizer( vlc_object_t * );
  84 static void CloseDecoder  ( vlc_object_t * );
  85 static void *DecodeBlock  ( decoder_t *, block_t ** );
  86
  87 static int  SyncInfo      ( const uint8_t *, unsigned int *, unsigned int *,
  88                             unsigned int *, int * );
  89
  90 static uint8_t       *GetOutBuffer ( decoder_t *, void ** );
  91 static aout_buffer_t *GetAoutBuffer( decoder_t * );
  92 static block_t       *GetSoutBuffer( decoder_t * );
  93
  94 /*****************************************************************************
  95  * Module descriptor
  96  *****************************************************************************/
  97 vlc_module_begin();
  98     set_description( N_("A/52 parser") );
  99     set_capability( "decoder", 100 );
 100     set_callbacks( OpenDecoder, CloseDecoder );
 101     set_category( CAT_INPUT );
 102     set_subcategory( SUBCAT_INPUT_ACODEC );
 103
 104     add_submodule();
 105     set_description( N_("A/52 audio packetizer") );
 106     set_capability( "packetizer", 10 );
 107     set_callbacks( OpenPacketizer, CloseDecoder );
 108 vlc_module_end();
 109
 110 /*****************************************************************************
 111  * OpenDecoder: probe the decoder and return score
 112  *****************************************************************************/
 113 static int OpenDecoder( vlc_object_t *p_this )
 114 {
 115     decoder_t *p_dec = (decoder_t*)p_this;
 116     decoder_sys_t *p_sys;
 117
 118     if( p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2',' ')
 119           && p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2','b') )
 120     {
 121         return VLC_EGENERIC;
 122     }
 123
 124     /* Allocate the memory needed to store the decoder's structure */
 125     if( ( p_dec->p_sys = p_sys =
 126           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 127         return VLC_ENOMEM;
 128
 129     /* Misc init */
 130     p_sys->b_packetizer = false;
 131     p_sys->i_state = STATE_NOSYNC;
 132     aout_DateSet( &p_sys->end_date, 0 );
 133
 134     p_sys->bytestream = block_BytestreamInit();
 135     p_sys->i_input_rate = INPUT_RATE_DEFAULT;
 136
 137     /* Set output properties */
 138     p_dec->fmt_out.i_cat = AUDIO_ES;
 139     p_dec->fmt_out.i_codec = VLC_FOURCC('a','5','2',' ');
 140     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 141
 142     /* Set callback */
 143     p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 144         DecodeBlock;
 145     p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 146         DecodeBlock;
 147
 148     return VLC_SUCCESS;
 149 }
 150
 151 static int OpenPacketizer( vlc_object_t *p_this )
 152 {
 153     decoder_t *p_dec = (decoder_t*)p_this;
 154
 155     int i_ret = OpenDecoder( p_this );
 156
 157     if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = true;
 158
 159     return i_ret;
 160 }
 161
 162 /****************************************************************************
 163  * DecodeBlock: the whole thing
 164  ****************************************************************************
 165  * This function is called just after the thread is launched.
 166  ****************************************************************************/
 167 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 168 {
 169     decoder_sys_t *p_sys = p_dec->p_sys;
 170     uint8_t p_header[A52_HEADER_SIZE];
 171     uint8_t *p_buf;
 172     void *p_out_buffer;
 173
 174     if( !pp_block || !*pp_block ) return NULL;
 175
 176     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 177     {
 178         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 179         {
 180             p_sys->i_state = STATE_NOSYNC;
 181             block_BytestreamFlush( &p_sys->bytestream );
 182         }
 183 //        aout_DateSet( &p_sys->end_date, 0 );
 184         block_Release( *pp_block );
 185         return NULL;
 186     }
 187
 188     if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
 189     {
 190         /* We've just started the stream, wait for the first PTS. */
 191         block_Release( *pp_block );
 192         return NULL;
 193     }
 194
 195     if( (*pp_block)->i_rate > 0 )
 196         p_sys->i_input_rate = (*pp_block)->i_rate;
 197
 198     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 199
 200     while( 1 )
 201     {
 202         switch( p_sys->i_state )
 203         {
 204         case STATE_NOSYNC:
 205             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 206                    == VLC_SUCCESS )
 207             {
 208                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 209                 {
 210                     p_sys->i_state = STATE_SYNC;
 211                     break;
 212                 }
 213                 block_SkipByte( &p_sys->bytestream );
 214             }
 215             if( p_sys->i_state != STATE_SYNC )
 216             {
 217                 block_BytestreamFlush( &p_sys->bytestream );
 218
 219                 /* Need more data */
 220                 return NULL;
 221             }
 222
 223         case STATE_SYNC:
 224             /* New frame, set the Presentation Time Stamp */
 225             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 226             if( p_sys->i_pts != 0 &&
 227                 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
 228             {
 229                 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 230             }
 231             p_sys->i_state = STATE_HEADER;
 232
 233         case STATE_HEADER:
 234             /* Get A/52 frame header (A52_HEADER_SIZE bytes) */
 235             if( block_PeekBytes( &p_sys->bytestream, p_header,
 236                                  A52_HEADER_SIZE ) != VLC_SUCCESS )
 237             {
 238                 /* Need more data */
 239                 return NULL;
 240             }
 241
 242             /* Check if frame is valid and get frame info */
 243             p_sys->i_frame_size = SyncInfo( p_header,
 244                                             &p_sys->i_channels,
 245                                             &p_sys->i_channels_conf,
 246                                             &p_sys->i_rate,
 247                                             &p_sys->i_bit_rate );
 248             if( !p_sys->i_frame_size )
 249             {
 250                 msg_Dbg( p_dec, "emulated sync word" );
 251                 block_SkipByte( &p_sys->bytestream );
 252                 p_sys->i_state = STATE_NOSYNC;
 253                 break;
 254             }
 255             p_sys->i_state = STATE_NEXT_SYNC;
 256
 257         case STATE_NEXT_SYNC:
 258             /* TODO: If pp_block == NULL, flush the buffer without checking the
 259              * next sync word */
 260
 261             /* Check if next expected frame contains the sync word */
 262             if( block_PeekOffsetBytes( &p_sys->bytestream,
 263                                        p_sys->i_frame_size, p_header, 2 )
 264                 != VLC_SUCCESS )
 265             {
 266                 /* Need more data */
 267                 return NULL;
 268             }
 269
 270             if( p_sys->b_packetizer &&
 271                 p_header[0] == 0 && p_header[1] == 0 )
 272             {
 273                 /* A52 wav files and audio CD's use stuffing */
 274                 p_sys->i_state = STATE_GET_DATA;
 275                 break;
 276             }
 277
 278             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 279             {
 280                 msg_Dbg( p_dec, "emulated sync word "
 281                          "(no sync on following frame)" );
 282                 p_sys->i_state = STATE_NOSYNC;
 283                 block_SkipByte( &p_sys->bytestream );
 284                 break;
 285             }
 286             p_sys->i_state = STATE_SEND_DATA;
 287             break;
 288
 289         case STATE_GET_DATA:
 290             /* Make sure we have enough data.
 291              * (Not useful if we went through NEXT_SYNC) */
 292             if( block_WaitBytes( &p_sys->bytestream,
 293                                  p_sys->i_frame_size ) != VLC_SUCCESS )
 294             {
 295                 /* Need more data */
 296                 return NULL;
 297             }
 298             p_sys->i_state = STATE_SEND_DATA;
 299
 300         case STATE_SEND_DATA:
 301             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 302             {
 303                 //p_dec->b_error = true;
 304                 return NULL;
 305             }
 306
 307             /* Copy the whole frame into the buffer. When we reach this point
 308              * we already know we have enough data available. */
 309             block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
 310
 311             /* Make sure we don't reuse the same pts twice */
 312             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 313                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
 314
 315             /* So p_block doesn't get re-added several times */
 316             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 317
 318             p_sys->i_state = STATE_NOSYNC;
 319
 320             return p_out_buffer;
 321         }
 322     }
 323
 324     return NULL;
 325 }
 326
 327 /*****************************************************************************
 328  * CloseDecoder: clean up the decoder
 329  *****************************************************************************/
 330 static void CloseDecoder( vlc_object_t *p_this )
 331 {
 332     decoder_t *p_dec = (decoder_t*)p_this;
 333     decoder_sys_t *p_sys = p_dec->p_sys;
 334
 335     block_BytestreamRelease( &p_sys->bytestream );
 336
 337     free( p_sys );
 338 }
 339
 340 /*****************************************************************************
 341  * GetOutBuffer:
 342  *****************************************************************************/
 343 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
 344 {
 345     decoder_sys_t *p_sys = p_dec->p_sys;
 346     uint8_t *p_buf;
 347
 348     if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
 349     {
 350         msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 351                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 352
 353         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 354         aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 355     }
 356
 357     p_dec->fmt_out.audio.i_rate     = p_sys->i_rate;
 358     p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
 359     p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
 360     p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
 361
 362     p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
 363     p_dec->fmt_out.audio.i_physical_channels =
 364         p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 365
 366     p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
 367
 368     if( p_sys->b_packetizer )
 369     {
 370         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 371         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 372         *pp_out_buffer = p_sout_buffer;
 373     }
 374     else
 375     {
 376         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 377         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 378         *pp_out_buffer = p_aout_buffer;
 379     }
 380
 381     return p_buf;
 382 }
 383
 384 /*****************************************************************************
 385  * GetAoutBuffer:
 386  *****************************************************************************/
 387 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 388 {
 389     decoder_sys_t *p_sys = p_dec->p_sys;
 390     aout_buffer_t *p_buf;
 391
 392     p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB  );
 393     if( p_buf == NULL ) return NULL;
 394
 395     p_buf->start_date = aout_DateGet( &p_sys->end_date );
 396     p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 397                                           A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
 398
 399     return p_buf;
 400 }
 401
 402 /*****************************************************************************
 403  * GetSoutBuffer:
 404  *****************************************************************************/
 405 static block_t *GetSoutBuffer( decoder_t *p_dec )
 406 {
 407     decoder_sys_t *p_sys = p_dec->p_sys;
 408     block_t *p_block;
 409
 410     p_block = block_New( p_dec, p_sys->i_frame_size );
 411     if( p_block == NULL ) return NULL;
 412
 413     p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 414
 415     p_block->i_length =
 416         aout_DateIncrement( &p_sys->end_date,
 417                             A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
 418             p_block->i_pts;
 419
 420     return p_block;
 421 }
 422
 423 /*****************************************************************************
 424  * SyncInfo: parse A/52 sync info
 425  *****************************************************************************
 426  * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
 427  * since we don't want to oblige S/PDIF people to use liba52 just to get
 428  * their SyncInfo...
 429  *****************************************************************************/
 430 static int SyncInfo( const uint8_t * p_buf,
 431                      unsigned int * pi_channels,
 432                      unsigned int * pi_channels_conf,
 433                      unsigned int * pi_sample_rate, int * pi_bit_rate )
 434 {
 435     static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
 436     static const int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
 437                                 128, 160, 192, 224, 256, 320, 384, 448,
 438                                 512, 576, 640 };
 439     static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
 440                                       0x04, 0x01, 0x04, 0x01 };
 441     int frmsizecod;
 442     int bitrate;
 443     int half;
 444     int acmod;
 445
 446     if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77))        /* syncword */
 447         return 0;
 448
 449     if (p_buf[5] >= 0x60)                /* bsid >= 12 */
 450         return 0;
 451     half = halfrate[p_buf[5] >> 3];
 452
 453     /* acmod, dsurmod and lfeon */
 454     acmod = p_buf[6] >> 5;
 455     if ( (p_buf[6] & 0xf8) == 0x50 )
 456     {
 457         /* Dolby surround = stereo + Dolby */
 458         *pi_channels = 2;
 459         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 460                             | AOUT_CHAN_DOLBYSTEREO;
 461     }
 462     else switch ( acmod )
 463     {
 464     case 0x0:
 465         /* Dual-mono = stereo + dual-mono */
 466         *pi_channels = 2;
 467         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 468                             | AOUT_CHAN_DUALMONO;
 469         break;
 470     case 0x1:
 471         /* Mono */
 472         *pi_channels = 1;
 473         *pi_channels_conf = AOUT_CHAN_CENTER;
 474         break;
 475     case 0x2:
 476         /* Stereo */
 477         *pi_channels = 2;
 478         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 479         break;
 480     case 0x3:
 481         /* 3F */
 482         *pi_channels = 3;
 483         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 484                             | AOUT_CHAN_CENTER;
 485         break;
 486     case 0x4:
 487         /* 2F1R */
 488         *pi_channels = 3;
 489         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 490                             | AOUT_CHAN_REARCENTER;
 491         break;
 492     case 0x5:
 493         /* 3F1R */
 494         *pi_channels = 4;
 495         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 496                             | AOUT_CHAN_REARCENTER;
 497         break;
 498     case 0x6:
 499         /* 2F2R */
 500         *pi_channels = 4;
 501         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 502                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 503         break;
 504     case 0x7:
 505         /* 3F2R */
 506         *pi_channels = 5;
 507         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 508                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 509         break;
 510     default:
 511         return 0;
 512     }
 513
 514     if ( p_buf[6] & lfeon[acmod] )
 515     {
 516         (*pi_channels)++;
 517         *pi_channels_conf |= AOUT_CHAN_LFE;
 518     }
 519
 520     frmsizecod = p_buf[4] & 63;
 521     if (frmsizecod >= 38)
 522         return 0;
 523     bitrate = rate [frmsizecod >> 1];
 524     *pi_bit_rate = (bitrate * 1000) >> half;
 525
 526     switch (p_buf[4] & 0xc0) {
 527     case 0:
 528         *pi_sample_rate = 48000 >> half;
 529         return 4 * bitrate;
 530     case 0x40:
 531         *pi_sample_rate = 44100 >> half;
 532         return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
 533     case 0x80:
 534         *pi_sample_rate = 32000 >> half;
 535         return 6 * bitrate;
 536     default:
 537         return 0;
 538     }
 539 }