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 #include <vlc/vlc.h>
  30 #include <vlc_codec.h>
  31 #include <vlc_aout.h>
  32 #include <vlc_input.h>
  33 #include <vlc_block_helper.h>
  34
  35 #define A52_HEADER_SIZE 7
  36
  37 /*****************************************************************************
  38  * decoder_sys_t : decoder descriptor
  39  *****************************************************************************/
  40 struct decoder_sys_t
  41 {
  42     /* Module mode */
  43     vlc_bool_t b_packetizer;
  44
  45     /*
  46      * Input properties
  47      */
  48     int i_state;
  49
  50     block_bytestream_t bytestream;
  51
  52     /*
  53      * Common properties
  54      */
  55     audio_date_t   end_date;
  56
  57     mtime_t i_pts;
  58     int i_frame_size, i_bit_rate;
  59     unsigned int i_rate, i_channels, i_channels_conf;
  60
  61     int i_input_rate;
  62 };
  63
  64 enum {
  65
  66     STATE_NOSYNC,
  67     STATE_SYNC,
  68     STATE_HEADER,
  69     STATE_NEXT_SYNC,
  70     STATE_GET_DATA,
  71     STATE_SEND_DATA
  72 };
  73
  74 /****************************************************************************
  75  * Local prototypes
  76  ****************************************************************************/
  77 static int  OpenDecoder   ( vlc_object_t * );
  78 static int  OpenPacketizer( vlc_object_t * );
  79 static void CloseDecoder  ( vlc_object_t * );
  80 static void *DecodeBlock  ( decoder_t *, block_t ** );
  81
  82 static int  SyncInfo      ( const byte_t *, unsigned int *, unsigned int *,
  83                             unsigned int *, int * );
  84
  85 static uint8_t       *GetOutBuffer ( decoder_t *, void ** );
  86 static aout_buffer_t *GetAoutBuffer( decoder_t * );
  87 static block_t       *GetSoutBuffer( decoder_t * );
  88
  89 /*****************************************************************************
  90  * Module descriptor
  91  *****************************************************************************/
  92 vlc_module_begin();
  93     set_description( _("A/52 parser") );
  94     set_capability( "decoder", 100 );
  95     set_callbacks( OpenDecoder, CloseDecoder );
  96     set_category( CAT_INPUT );
  97     set_subcategory( SUBCAT_INPUT_ACODEC );
  98
  99     add_submodule();
 100     set_description( _("A/52 audio packetizer") );
 101     set_capability( "packetizer", 10 );
 102     set_callbacks( OpenPacketizer, CloseDecoder );
 103 vlc_module_end();
 104
 105 /*****************************************************************************
 106  * OpenDecoder: probe the decoder and return score
 107  *****************************************************************************/
 108 static int OpenDecoder( vlc_object_t *p_this )
 109 {
 110     decoder_t *p_dec = (decoder_t*)p_this;
 111     decoder_sys_t *p_sys;
 112
 113     if( p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2',' ')
 114           && p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2','b') )
 115     {
 116         return VLC_EGENERIC;
 117     }
 118
 119     /* Allocate the memory needed to store the decoder's structure */
 120     if( ( p_dec->p_sys = p_sys =
 121           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 122     {
 123         msg_Err( p_dec, "out of memory" );
 124         return VLC_EGENERIC;
 125     }
 126
 127     /* Misc init */
 128     p_sys->b_packetizer = VLC_FALSE;
 129     p_sys->i_state = STATE_NOSYNC;
 130     aout_DateSet( &p_sys->end_date, 0 );
 131
 132     p_sys->bytestream = block_BytestreamInit( p_dec );
 133     p_sys->i_input_rate = INPUT_RATE_DEFAULT;
 134
 135     /* Set output properties */
 136     p_dec->fmt_out.i_cat = AUDIO_ES;
 137     p_dec->fmt_out.i_codec = VLC_FOURCC('a','5','2',' ');
 138     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 139
 140     /* Set callback */
 141     p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 142         DecodeBlock;
 143     p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 144         DecodeBlock;
 145
 146     return VLC_SUCCESS;
 147 }
 148
 149 static int OpenPacketizer( vlc_object_t *p_this )
 150 {
 151     decoder_t *p_dec = (decoder_t*)p_this;
 152
 153     int i_ret = OpenDecoder( p_this );
 154
 155     if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = VLC_TRUE;
 156
 157     return i_ret;
 158 }
 159
 160 /****************************************************************************
 161  * DecodeBlock: the whole thing
 162  ****************************************************************************
 163  * This function is called just after the thread is launched.
 164  ****************************************************************************/
 165 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 166 {
 167     decoder_sys_t *p_sys = p_dec->p_sys;
 168     uint8_t p_header[A52_HEADER_SIZE];
 169     uint8_t *p_buf;
 170     void *p_out_buffer;
 171
 172     if( !pp_block || !*pp_block ) return NULL;
 173
 174     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 175     {
 176         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 177         {
 178             p_sys->i_state = STATE_NOSYNC;
 179             block_BytestreamFlush( &p_sys->bytestream );
 180         }
 181 //        aout_DateSet( &p_sys->end_date, 0 );
 182         block_Release( *pp_block );
 183         return NULL;
 184     }
 185
 186     if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
 187     {
 188         /* We've just started the stream, wait for the first PTS. */
 189         block_Release( *pp_block );
 190         return NULL;
 191     }
 192
 193     if( (*pp_block)->i_rate > 0 )
 194         p_sys->i_input_rate = (*pp_block)->i_rate;
 195
 196     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 197
 198     while( 1 )
 199     {
 200         switch( p_sys->i_state )
 201         {
 202         case STATE_NOSYNC:
 203             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 204                    == VLC_SUCCESS )
 205             {
 206                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 207                 {
 208                     p_sys->i_state = STATE_SYNC;
 209                     break;
 210                 }
 211                 block_SkipByte( &p_sys->bytestream );
 212             }
 213             if( p_sys->i_state != STATE_SYNC )
 214             {
 215                 block_BytestreamFlush( &p_sys->bytestream );
 216
 217                 /* Need more data */
 218                 return NULL;
 219             }
 220
 221         case STATE_SYNC:
 222             /* New frame, set the Presentation Time Stamp */
 223             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 224             if( p_sys->i_pts != 0 &&
 225                 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
 226             {
 227                 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 228             }
 229             p_sys->i_state = STATE_HEADER;
 230
 231         case STATE_HEADER:
 232             /* Get A/52 frame header (A52_HEADER_SIZE bytes) */
 233             if( block_PeekBytes( &p_sys->bytestream, p_header,
 234                                  A52_HEADER_SIZE ) != VLC_SUCCESS )
 235             {
 236                 /* Need more data */
 237                 return NULL;
 238             }
 239
 240             /* Check if frame is valid and get frame info */
 241             p_sys->i_frame_size = SyncInfo( p_header,
 242                                             &p_sys->i_channels,
 243                                             &p_sys->i_channels_conf,
 244                                             &p_sys->i_rate,
 245                                             &p_sys->i_bit_rate );
 246             if( !p_sys->i_frame_size )
 247             {
 248                 msg_Dbg( p_dec, "emulated sync word" );
 249                 block_SkipByte( &p_sys->bytestream );
 250                 p_sys->i_state = STATE_NOSYNC;
 251                 break;
 252             }
 253             p_sys->i_state = STATE_NEXT_SYNC;
 254
 255         case STATE_NEXT_SYNC:
 256             /* TODO: If pp_block == NULL, flush the buffer without checking the
 257              * next sync word */
 258
 259             /* Check if next expected frame contains the sync word */
 260             if( block_PeekOffsetBytes( &p_sys->bytestream,
 261                                        p_sys->i_frame_size, p_header, 2 )
 262                 != VLC_SUCCESS )
 263             {
 264                 /* Need more data */
 265                 return NULL;
 266             }
 267
 268             if( p_sys->b_packetizer &&
 269                 p_header[0] == 0 && p_header[1] == 0 )
 270             {
 271                 /* A52 wav files and audio CD's use stuffing */
 272                 p_sys->i_state = STATE_GET_DATA;
 273                 break;
 274             }
 275
 276             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 277             {
 278                 msg_Dbg( p_dec, "emulated sync word "
 279                          "(no sync on following frame)" );
 280                 p_sys->i_state = STATE_NOSYNC;
 281                 block_SkipByte( &p_sys->bytestream );
 282                 break;
 283             }
 284             p_sys->i_state = STATE_SEND_DATA;
 285             break;
 286
 287         case STATE_GET_DATA:
 288             /* Make sure we have enough data.
 289              * (Not useful if we went through NEXT_SYNC) */
 290             if( block_WaitBytes( &p_sys->bytestream,
 291                                  p_sys->i_frame_size ) != VLC_SUCCESS )
 292             {
 293                 /* Need more data */
 294                 return NULL;
 295             }
 296             p_sys->i_state = STATE_SEND_DATA;
 297
 298         case STATE_SEND_DATA:
 299             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 300             {
 301                 //p_dec->b_error = VLC_TRUE;
 302                 return NULL;
 303             }
 304
 305             /* Copy the whole frame into the buffer. When we reach this point
 306              * we already know we have enough data available. */
 307             block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
 308
 309             /* Make sure we don't reuse the same pts twice */
 310             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 311                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
 312
 313             /* So p_block doesn't get re-added several times */
 314             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 315
 316             p_sys->i_state = STATE_NOSYNC;
 317
 318             return p_out_buffer;
 319         }
 320     }
 321
 322     return NULL;
 323 }
 324
 325 /*****************************************************************************
 326  * CloseDecoder: clean up the decoder
 327  *****************************************************************************/
 328 static void CloseDecoder( vlc_object_t *p_this )
 329 {
 330     decoder_t *p_dec = (decoder_t*)p_this;
 331     decoder_sys_t *p_sys = p_dec->p_sys;
 332
 333     block_BytestreamRelease( &p_sys->bytestream );
 334
 335     free( p_sys );
 336 }
 337
 338 /*****************************************************************************
 339  * GetOutBuffer:
 340  *****************************************************************************/
 341 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
 342 {
 343     decoder_sys_t *p_sys = p_dec->p_sys;
 344     uint8_t *p_buf;
 345
 346     if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
 347     {
 348         msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 349                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 350
 351         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 352         aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 353     }
 354
 355     p_dec->fmt_out.audio.i_rate     = p_sys->i_rate;
 356     p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
 357     p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
 358     p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
 359
 360     p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
 361     p_dec->fmt_out.audio.i_physical_channels =
 362         p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 363
 364     p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
 365
 366     if( p_sys->b_packetizer )
 367     {
 368         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 369         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 370         *pp_out_buffer = p_sout_buffer;
 371     }
 372     else
 373     {
 374         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 375         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 376         *pp_out_buffer = p_aout_buffer;
 377     }
 378
 379     return p_buf;
 380 }
 381
 382 /*****************************************************************************
 383  * GetAoutBuffer:
 384  *****************************************************************************/
 385 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 386 {
 387     decoder_sys_t *p_sys = p_dec->p_sys;
 388     aout_buffer_t *p_buf;
 389
 390     p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB  );
 391     if( p_buf == NULL ) return NULL;
 392
 393     p_buf->start_date = aout_DateGet( &p_sys->end_date );
 394     p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 395                                           A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
 396
 397     return p_buf;
 398 }
 399
 400 /*****************************************************************************
 401  * GetSoutBuffer:
 402  *****************************************************************************/
 403 static block_t *GetSoutBuffer( decoder_t *p_dec )
 404 {
 405     decoder_sys_t *p_sys = p_dec->p_sys;
 406     block_t *p_block;
 407
 408     p_block = block_New( p_dec, p_sys->i_frame_size );
 409     if( p_block == NULL ) return NULL;
 410
 411     p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 412
 413     p_block->i_length =
 414         aout_DateIncrement( &p_sys->end_date,
 415                             A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
 416             p_block->i_pts;
 417
 418     return p_block;
 419 }
 420
 421 /*****************************************************************************
 422  * SyncInfo: parse A/52 sync info
 423  *****************************************************************************
 424  * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
 425  * since we don't want to oblige S/PDIF people to use liba52 just to get
 426  * their SyncInfo...
 427  *****************************************************************************/
 428 static int SyncInfo( const byte_t * p_buf,
 429                      unsigned int * pi_channels,
 430                      unsigned int * pi_channels_conf,
 431                      unsigned int * pi_sample_rate, int * pi_bit_rate )
 432 {
 433     static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
 434     static const int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
 435                                 128, 160, 192, 224, 256, 320, 384, 448,
 436                                 512, 576, 640 };
 437     static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
 438                                       0x04, 0x01, 0x04, 0x01 };
 439     int frmsizecod;
 440     int bitrate;
 441     int half;
 442     int acmod;
 443
 444     if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77))        /* syncword */
 445         return 0;
 446
 447     if (p_buf[5] >= 0x60)                /* bsid >= 12 */
 448         return 0;
 449     half = halfrate[p_buf[5] >> 3];
 450
 451     /* acmod, dsurmod and lfeon */
 452     acmod = p_buf[6] >> 5;
 453     if ( (p_buf[6] & 0xf8) == 0x50 )
 454     {
 455         /* Dolby surround = stereo + Dolby */
 456         *pi_channels = 2;
 457         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 458                             | AOUT_CHAN_DOLBYSTEREO;
 459     }
 460     else switch ( acmod )
 461     {
 462     case 0x0:
 463         /* Dual-mono = stereo + dual-mono */
 464         *pi_channels = 2;
 465         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 466                             | AOUT_CHAN_DUALMONO;
 467         break;
 468     case 0x1:
 469         /* Mono */
 470         *pi_channels = 1;
 471         *pi_channels_conf = AOUT_CHAN_CENTER;
 472         break;
 473     case 0x2:
 474         /* Stereo */
 475         *pi_channels = 2;
 476         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 477         break;
 478     case 0x3:
 479         /* 3F */
 480         *pi_channels = 3;
 481         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 482                             | AOUT_CHAN_CENTER;
 483         break;
 484     case 0x4:
 485         /* 2F1R */
 486         *pi_channels = 3;
 487         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 488                             | AOUT_CHAN_REARCENTER;
 489         break;
 490     case 0x5:
 491         /* 3F1R */
 492         *pi_channels = 4;
 493         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 494                             | AOUT_CHAN_REARCENTER;
 495         break;
 496     case 0x6:
 497         /* 2F2R */
 498         *pi_channels = 4;
 499         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 500                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 501         break;
 502     case 0x7:
 503         /* 3F2R */
 504         *pi_channels = 5;
 505         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 506                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 507         break;
 508     default:
 509         return 0;
 510     }
 511
 512     if ( p_buf[6] & lfeon[acmod] )
 513     {
 514         (*pi_channels)++;
 515         *pi_channels_conf |= AOUT_CHAN_LFE;
 516     }
 517
 518     frmsizecod = p_buf[4] & 63;
 519     if (frmsizecod >= 38)
 520         return 0;
 521     bitrate = rate [frmsizecod >> 1];
 522     *pi_bit_rate = (bitrate * 1000) >> half;
 523
 524     switch (p_buf[4] & 0xc0) {
 525     case 0:
 526         *pi_sample_rate = 48000 >> half;
 527         return 4 * bitrate;
 528     case 0x40:
 529         *pi_sample_rate = 44100 >> half;
 530         return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
 531     case 0x80:
 532         *pi_sample_rate = 32000 >> half;
 533         return 6 * bitrate;
 534     default:
 535         return 0;
 536     }
 537 }