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( _("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( _("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     {
 128         msg_Err( p_dec, "out of memory" );
 129         return VLC_EGENERIC;
 130     }
 131
 132     /* Misc init */
 133     p_sys->b_packetizer = false;
 134     p_sys->i_state = STATE_NOSYNC;
 135     aout_DateSet( &p_sys->end_date, 0 );
 136
 137     p_sys->bytestream = block_BytestreamInit();
 138     p_sys->i_input_rate = INPUT_RATE_DEFAULT;
 139
 140     /* Set output properties */
 141     p_dec->fmt_out.i_cat = AUDIO_ES;
 142     p_dec->fmt_out.i_codec = VLC_FOURCC('a','5','2',' ');
 143     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 144
 145     /* Set callback */
 146     p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 147         DecodeBlock;
 148     p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 149         DecodeBlock;
 150
 151     return VLC_SUCCESS;
 152 }
 153
 154 static int OpenPacketizer( vlc_object_t *p_this )
 155 {
 156     decoder_t *p_dec = (decoder_t*)p_this;
 157
 158     int i_ret = OpenDecoder( p_this );
 159
 160     if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = true;
 161
 162     return i_ret;
 163 }
 164
 165 /****************************************************************************
 166  * DecodeBlock: the whole thing
 167  ****************************************************************************
 168  * This function is called just after the thread is launched.
 169  ****************************************************************************/
 170 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 171 {
 172     decoder_sys_t *p_sys = p_dec->p_sys;
 173     uint8_t p_header[A52_HEADER_SIZE];
 174     uint8_t *p_buf;
 175     void *p_out_buffer;
 176
 177     if( !pp_block || !*pp_block ) return NULL;
 178
 179     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 180     {
 181         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 182         {
 183             p_sys->i_state = STATE_NOSYNC;
 184             block_BytestreamFlush( &p_sys->bytestream );
 185         }
 186 //        aout_DateSet( &p_sys->end_date, 0 );
 187         block_Release( *pp_block );
 188         return NULL;
 189     }
 190
 191     if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
 192     {
 193         /* We've just started the stream, wait for the first PTS. */
 194         block_Release( *pp_block );
 195         return NULL;
 196     }
 197
 198     if( (*pp_block)->i_rate > 0 )
 199         p_sys->i_input_rate = (*pp_block)->i_rate;
 200
 201     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 202
 203     while( 1 )
 204     {
 205         switch( p_sys->i_state )
 206         {
 207         case STATE_NOSYNC:
 208             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 209                    == VLC_SUCCESS )
 210             {
 211                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 212                 {
 213                     p_sys->i_state = STATE_SYNC;
 214                     break;
 215                 }
 216                 block_SkipByte( &p_sys->bytestream );
 217             }
 218             if( p_sys->i_state != STATE_SYNC )
 219             {
 220                 block_BytestreamFlush( &p_sys->bytestream );
 221
 222                 /* Need more data */
 223                 return NULL;
 224             }
 225
 226         case STATE_SYNC:
 227             /* New frame, set the Presentation Time Stamp */
 228             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 229             if( p_sys->i_pts != 0 &&
 230                 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
 231             {
 232                 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 233             }
 234             p_sys->i_state = STATE_HEADER;
 235
 236         case STATE_HEADER:
 237             /* Get A/52 frame header (A52_HEADER_SIZE bytes) */
 238             if( block_PeekBytes( &p_sys->bytestream, p_header,
 239                                  A52_HEADER_SIZE ) != VLC_SUCCESS )
 240             {
 241                 /* Need more data */
 242                 return NULL;
 243             }
 244
 245             /* Check if frame is valid and get frame info */
 246             p_sys->i_frame_size = SyncInfo( p_header,
 247                                             &p_sys->i_channels,
 248                                             &p_sys->i_channels_conf,
 249                                             &p_sys->i_rate,
 250                                             &p_sys->i_bit_rate );
 251             if( !p_sys->i_frame_size )
 252             {
 253                 msg_Dbg( p_dec, "emulated sync word" );
 254                 block_SkipByte( &p_sys->bytestream );
 255                 p_sys->i_state = STATE_NOSYNC;
 256                 break;
 257             }
 258             p_sys->i_state = STATE_NEXT_SYNC;
 259
 260         case STATE_NEXT_SYNC:
 261             /* TODO: If pp_block == NULL, flush the buffer without checking the
 262              * next sync word */
 263
 264             /* Check if next expected frame contains the sync word */
 265             if( block_PeekOffsetBytes( &p_sys->bytestream,
 266                                        p_sys->i_frame_size, p_header, 2 )
 267                 != VLC_SUCCESS )
 268             {
 269                 /* Need more data */
 270                 return NULL;
 271             }
 272
 273             if( p_sys->b_packetizer &&
 274                 p_header[0] == 0 && p_header[1] == 0 )
 275             {
 276                 /* A52 wav files and audio CD's use stuffing */
 277                 p_sys->i_state = STATE_GET_DATA;
 278                 break;
 279             }
 280
 281             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 282             {
 283                 msg_Dbg( p_dec, "emulated sync word "
 284                          "(no sync on following frame)" );
 285                 p_sys->i_state = STATE_NOSYNC;
 286                 block_SkipByte( &p_sys->bytestream );
 287                 break;
 288             }
 289             p_sys->i_state = STATE_SEND_DATA;
 290             break;
 291
 292         case STATE_GET_DATA:
 293             /* Make sure we have enough data.
 294              * (Not useful if we went through NEXT_SYNC) */
 295             if( block_WaitBytes( &p_sys->bytestream,
 296                                  p_sys->i_frame_size ) != VLC_SUCCESS )
 297             {
 298                 /* Need more data */
 299                 return NULL;
 300             }
 301             p_sys->i_state = STATE_SEND_DATA;
 302
 303         case STATE_SEND_DATA:
 304             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 305             {
 306                 //p_dec->b_error = true;
 307                 return NULL;
 308             }
 309
 310             /* Copy the whole frame into the buffer. When we reach this point
 311              * we already know we have enough data available. */
 312             block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
 313
 314             /* Make sure we don't reuse the same pts twice */
 315             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 316                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
 317
 318             /* So p_block doesn't get re-added several times */
 319             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 320
 321             p_sys->i_state = STATE_NOSYNC;
 322
 323             return p_out_buffer;
 324         }
 325     }
 326
 327     return NULL;
 328 }
 329
 330 /*****************************************************************************
 331  * CloseDecoder: clean up the decoder
 332  *****************************************************************************/
 333 static void CloseDecoder( vlc_object_t *p_this )
 334 {
 335     decoder_t *p_dec = (decoder_t*)p_this;
 336     decoder_sys_t *p_sys = p_dec->p_sys;
 337
 338     block_BytestreamRelease( &p_sys->bytestream );
 339
 340     free( p_sys );
 341 }
 342
 343 /*****************************************************************************
 344  * GetOutBuffer:
 345  *****************************************************************************/
 346 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
 347 {
 348     decoder_sys_t *p_sys = p_dec->p_sys;
 349     uint8_t *p_buf;
 350
 351     if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
 352     {
 353         msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 354                   p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
 355
 356         aout_DateInit( &p_sys->end_date, p_sys->i_rate );
 357         aout_DateSet( &p_sys->end_date, p_sys->i_pts );
 358     }
 359
 360     p_dec->fmt_out.audio.i_rate     = p_sys->i_rate;
 361     p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
 362     p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
 363     p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
 364
 365     p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
 366     p_dec->fmt_out.audio.i_physical_channels =
 367         p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
 368
 369     p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
 370
 371     if( p_sys->b_packetizer )
 372     {
 373         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 374         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 375         *pp_out_buffer = p_sout_buffer;
 376     }
 377     else
 378     {
 379         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 380         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 381         *pp_out_buffer = p_aout_buffer;
 382     }
 383
 384     return p_buf;
 385 }
 386
 387 /*****************************************************************************
 388  * GetAoutBuffer:
 389  *****************************************************************************/
 390 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 391 {
 392     decoder_sys_t *p_sys = p_dec->p_sys;
 393     aout_buffer_t *p_buf;
 394
 395     p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB  );
 396     if( p_buf == NULL ) return NULL;
 397
 398     p_buf->start_date = aout_DateGet( &p_sys->end_date );
 399     p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 400                                           A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
 401
 402     return p_buf;
 403 }
 404
 405 /*****************************************************************************
 406  * GetSoutBuffer:
 407  *****************************************************************************/
 408 static block_t *GetSoutBuffer( decoder_t *p_dec )
 409 {
 410     decoder_sys_t *p_sys = p_dec->p_sys;
 411     block_t *p_block;
 412
 413     p_block = block_New( p_dec, p_sys->i_frame_size );
 414     if( p_block == NULL ) return NULL;
 415
 416     p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 417
 418     p_block->i_length =
 419         aout_DateIncrement( &p_sys->end_date,
 420                             A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
 421             p_block->i_pts;
 422
 423     return p_block;
 424 }
 425
 426 /*****************************************************************************
 427  * SyncInfo: parse A/52 sync info
 428  *****************************************************************************
 429  * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
 430  * since we don't want to oblige S/PDIF people to use liba52 just to get
 431  * their SyncInfo...
 432  *****************************************************************************/
 433 static int SyncInfo( const uint8_t * p_buf,
 434                      unsigned int * pi_channels,
 435                      unsigned int * pi_channels_conf,
 436                      unsigned int * pi_sample_rate, int * pi_bit_rate )
 437 {
 438     static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
 439     static const int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
 440                                 128, 160, 192, 224, 256, 320, 384, 448,
 441                                 512, 576, 640 };
 442     static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
 443                                       0x04, 0x01, 0x04, 0x01 };
 444     int frmsizecod;
 445     int bitrate;
 446     int half;
 447     int acmod;
 448
 449     if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77))        /* syncword */
 450         return 0;
 451
 452     if (p_buf[5] >= 0x60)                /* bsid >= 12 */
 453         return 0;
 454     half = halfrate[p_buf[5] >> 3];
 455
 456     /* acmod, dsurmod and lfeon */
 457     acmod = p_buf[6] >> 5;
 458     if ( (p_buf[6] & 0xf8) == 0x50 )
 459     {
 460         /* Dolby surround = stereo + Dolby */
 461         *pi_channels = 2;
 462         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 463                             | AOUT_CHAN_DOLBYSTEREO;
 464     }
 465     else switch ( acmod )
 466     {
 467     case 0x0:
 468         /* Dual-mono = stereo + dual-mono */
 469         *pi_channels = 2;
 470         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 471                             | AOUT_CHAN_DUALMONO;
 472         break;
 473     case 0x1:
 474         /* Mono */
 475         *pi_channels = 1;
 476         *pi_channels_conf = AOUT_CHAN_CENTER;
 477         break;
 478     case 0x2:
 479         /* Stereo */
 480         *pi_channels = 2;
 481         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 482         break;
 483     case 0x3:
 484         /* 3F */
 485         *pi_channels = 3;
 486         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 487                             | AOUT_CHAN_CENTER;
 488         break;
 489     case 0x4:
 490         /* 2F1R */
 491         *pi_channels = 3;
 492         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 493                             | AOUT_CHAN_REARCENTER;
 494         break;
 495     case 0x5:
 496         /* 3F1R */
 497         *pi_channels = 4;
 498         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 499                             | AOUT_CHAN_REARCENTER;
 500         break;
 501     case 0x6:
 502         /* 2F2R */
 503         *pi_channels = 4;
 504         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 505                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 506         break;
 507     case 0x7:
 508         /* 3F2R */
 509         *pi_channels = 5;
 510         *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 511                             | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 512         break;
 513     default:
 514         return 0;
 515     }
 516
 517     if ( p_buf[6] & lfeon[acmod] )
 518     {
 519         (*pi_channels)++;
 520         *pi_channels_conf |= AOUT_CHAN_LFE;
 521     }
 522
 523     frmsizecod = p_buf[4] & 63;
 524     if (frmsizecod >= 38)
 525         return 0;
 526     bitrate = rate [frmsizecod >> 1];
 527     *pi_bit_rate = (bitrate * 1000) >> half;
 528
 529     switch (p_buf[4] & 0xc0) {
 530     case 0:
 531         *pi_sample_rate = 48000 >> half;
 532         return 4 * bitrate;
 533     case 0x40:
 534         *pi_sample_rate = 44100 >> half;
 535         return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
 536     case 0x80:
 537         *pi_sample_rate = 32000 >> half;
 538         return 6 * bitrate;
 539     default:
 540         return 0;
 541     }
 542 }