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

   1 /*****************************************************************************
   2  * mpeg_audio.c: parse MPEG audio sync info and packetize the stream
   3  *****************************************************************************
   4  * Copyright (C) 2001-2003 VideoLAN
   5  * $Id: mpeg_audio.c,v 1.4 2003/01/15 23:55:22 massiot Exp $
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Eric Petit <titer@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29 #include <stdlib.h>                                      /* malloc(), free() */
  30 #include <string.h>                                              /* strdup() */
  31
  32 #include <vlc/vlc.h>
  33 #include <vlc/aout.h>
  34 #include <vlc/decoder.h>
  35
  36 /*****************************************************************************
  37  * dec_thread_t : decoder thread descriptor
  38  *****************************************************************************/
  39 typedef struct dec_thread_t
  40 {
  41     /*
  42      * Thread properties
  43      */
  44     vlc_thread_t        thread_id;                /* id for thread functions */
  45
  46     /*
  47      * Input properties
  48      */
  49     decoder_fifo_t *    p_fifo;                /* stores the PES stream data */
  50     bit_stream_t        bit_stream;
  51
  52     /*
  53      * Output properties
  54      */
  55     aout_instance_t *   p_aout; /* opaque */
  56     aout_input_t *      p_aout_input; /* opaque */
  57     audio_sample_format_t output_format;
  58 } dec_thread_t;
  59
  60 #define MAX_FRAME_SIZE (511 + 2048)
  61 /* This isn't the place to put mad-specific stuff. However, it makes the
  62  * mad plug-in's life much easier if we put 8 extra bytes at the end of the
  63  * buffer, because that way it doesn't have to copy the aout_buffer_t to a
  64  * bigger buffer. This has no implication on other plug-ins, and we only
  65  * lose 8 bytes per frame. --Meuuh */
  66 #define MAD_BUFFER_GUARD 8
  67
  68
  69 /****************************************************************************
  70  * Local prototypes
  71  ****************************************************************************/
  72 static int  Open           ( vlc_object_t * );
  73 static int  RunDecoder     ( decoder_fifo_t * );
  74
  75 static void EndThread      ( dec_thread_t * );
  76
  77 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
  78                      unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
  79                      unsigned int * pi_frame_length,
  80                      unsigned int * pi_current_frame_length,
  81                      unsigned int * pi_layer );
  82
  83 /*****************************************************************************
  84  * Module descriptor
  85  *****************************************************************************/
  86 vlc_module_begin();
  87     set_description( _("MPEG audio layer I/II/III parser") );
  88     set_capability( "decoder", 100 );
  89     set_callbacks( Open, NULL );
  90 vlc_module_end();
  91
  92 /*****************************************************************************
  93  * OpenDecoder: probe the decoder and return score
  94  *****************************************************************************/
  95 static int Open( vlc_object_t *p_this )
  96 {
  97     decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
  98
  99     if( p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', 'a') )
 100     {
 101         return VLC_EGENERIC;
 102     }
 103
 104     p_fifo->pf_run = RunDecoder;
 105     return VLC_SUCCESS;
 106 }
 107
 108 /*****************************************************************************
 109  * RunDecoder: this function is called just after the thread is created
 110  *****************************************************************************/
 111 static int RunDecoder( decoder_fifo_t *p_fifo )
 112 {
 113     dec_thread_t * p_dec;
 114     audio_date_t end_date;
 115     unsigned int i_layer = 0;
 116     byte_t p_sync[MAD_BUFFER_GUARD];
 117     mtime_t pts;
 118
 119     /* Allocate the memory needed to store the thread's structure */
 120     p_dec = malloc( sizeof(dec_thread_t) );
 121     if( p_dec == NULL )
 122     {
 123         msg_Err( p_fifo, "out of memory" );
 124         DecoderError( p_fifo );
 125         return -1;
 126     }
 127
 128     /* Initialize the thread properties */
 129     p_dec->p_aout = NULL;
 130     p_dec->p_aout_input = NULL;
 131     p_dec->p_fifo = p_fifo;
 132
 133     aout_DateSet( &end_date, 0 );
 134
 135     /* Init the bitstream */
 136     if( InitBitstream( &p_dec->bit_stream, p_dec->p_fifo,
 137                        NULL, NULL ) != VLC_SUCCESS )
 138     {
 139         msg_Err( p_fifo, "cannot initialize bitstream" );
 140         DecoderError( p_fifo );
 141         free( p_dec );
 142         return -1;
 143     }
 144
 145     /* Init sync buffer. */
 146     NextPTS( &p_dec->bit_stream, &pts, NULL );
 147     GetChunk( &p_dec->bit_stream, p_sync, MAD_BUFFER_GUARD );
 148
 149     /* Decoder thread's main loop */
 150     while ( !p_dec->p_fifo->b_die && !p_dec->p_fifo->b_error )
 151     {
 152         int i_bit_rate;
 153         unsigned int i_rate, i_original_channels, i_frame_size, i_frame_length;
 154         unsigned int i_new_layer, i_current_frame_size;
 155         uint32_t i_header;
 156         aout_buffer_t * p_buffer;
 157         int i;
 158
 159         /* Look for sync word - should be 0xffe */
 160         if ( (p_sync[0] != 0xff) || ((p_sync[1] & 0xe0) != 0xe0) )
 161         {
 162             msg_Warn( p_dec->p_fifo, "no sync - skipping" );
 163             /* Look inside the sync buffer. */
 164             for ( i = 1; i < MAD_BUFFER_GUARD - 1; i++ )
 165             {
 166                 if ( (p_sync[i] == 0xff) && ((p_sync[i + 1] & 0xe0) != 0xe0) )
 167                     break;
 168             }
 169             if ( i < MAD_BUFFER_GUARD - 1 )
 170             {
 171                 /* Found it ! */
 172                 memmove( p_sync, &p_sync[i], MAD_BUFFER_GUARD - i );
 173                 GetChunk( &p_dec->bit_stream, &p_sync[MAD_BUFFER_GUARD - i],
 174                           i );
 175             }
 176             else
 177             {
 178                 if ( p_sync[MAD_BUFFER_GUARD - 1] == 0xff
 179                       && ShowBits( &p_dec->bit_stream, 3 ) == 0x3 )
 180                 {
 181                     /* Found it ! */
 182                     p_sync[0] = p_sync[MAD_BUFFER_GUARD - 1];
 183                     GetChunk( &p_dec->bit_stream,
 184                               &p_sync[1], MAD_BUFFER_GUARD - 1 );
 185                 }
 186                 else
 187                 {
 188                     /* Scan the stream. */
 189                     while ( ShowBits( &p_dec->bit_stream, 11 ) != 0x07ff &&
 190                             (!p_dec->p_fifo->b_die) &&
 191                             (!p_dec->p_fifo->b_error) )
 192                     {
 193                         RemoveBits( &p_dec->bit_stream, 8 );
 194                     }
 195                     if ( p_dec->p_fifo->b_die || p_dec->p_fifo->b_error )
 196                         break;
 197                     GetChunk( &p_dec->bit_stream,p_sync, MAD_BUFFER_GUARD );
 198                 }
 199             }
 200         }
 201         if ( p_dec->p_fifo->b_die || p_dec->p_fifo->b_error ) break;
 202
 203         /* Set the Presentation Time Stamp */
 204         if ( pts != 0 && pts != aout_DateGet( &end_date ) )
 205         {
 206             aout_DateSet( &end_date, pts );
 207         }
 208
 209         /* Get frame header */
 210         i_header = (p_sync[0] << 24) | (p_sync[1] << 16) | (p_sync[2] << 8)
 211                      | p_sync[3];
 212
 213         /* Check if frame is valid and get frame info */
 214         i_current_frame_size = SyncInfo( i_header,
 215                                          &i_original_channels, &i_rate,
 216                                          &i_bit_rate, &i_frame_length,
 217                                          &i_frame_size, &i_new_layer );
 218
 219         if ( !i_current_frame_size )
 220         {
 221             msg_Warn( p_dec->p_fifo, "syncinfo failed" );
 222             /* This is probably an emulated startcode, drop the first byte
 223              * to force looking for the next startcode. */
 224             memmove( p_sync, &p_sync[1], MAD_BUFFER_GUARD - 1 );
 225             p_sync[MAD_BUFFER_GUARD - 1] = GetBits( &p_dec->bit_stream, 8 );
 226             continue;
 227         }
 228         if ( i_current_frame_size > i_frame_size )
 229         {
 230             msg_Warn( p_dec->p_fifo, "frame too big %d > %d",
 231                       i_current_frame_size, i_frame_size );
 232             memmove( p_sync, &p_sync[1], MAD_BUFFER_GUARD - 1 );
 233             p_sync[MAD_BUFFER_GUARD - 1] = GetBits( &p_dec->bit_stream, 8 );
 234             continue;
 235         }
 236
 237         if( (p_dec->p_aout_input != NULL) &&
 238             ( (p_dec->output_format.i_rate != i_rate)
 239                 || (p_dec->output_format.i_original_channels
 240                       != i_original_channels)
 241                 || (p_dec->output_format.i_bytes_per_frame
 242                       != i_frame_size + MAD_BUFFER_GUARD)
 243                 || (p_dec->output_format.i_frame_length != i_frame_length)
 244                 || (i_layer != i_new_layer) ) )
 245         {
 246             /* Parameters changed - this should not happen. */
 247             aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
 248             p_dec->p_aout_input = NULL;
 249         }
 250
 251         /* Creating the audio input if not created yet. */
 252         if( p_dec->p_aout_input == NULL )
 253         {
 254             i_layer = i_new_layer;
 255             if ( i_layer == 3 )
 256             {
 257                 p_dec->output_format.i_format = VLC_FOURCC('m','p','g','3');
 258             }
 259             else
 260             {
 261                 p_dec->output_format.i_format = VLC_FOURCC('m','p','g','a');
 262             }
 263             p_dec->output_format.i_rate = i_rate;
 264             p_dec->output_format.i_original_channels = i_original_channels;
 265             p_dec->output_format.i_physical_channels
 266                        = i_original_channels & AOUT_CHAN_PHYSMASK;
 267             p_dec->output_format.i_bytes_per_frame = i_frame_size
 268                                                         + MAD_BUFFER_GUARD;
 269             p_dec->output_format.i_frame_length = i_frame_length;
 270             aout_DateInit( &end_date, i_rate );
 271             p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo,
 272                                                &p_dec->p_aout,
 273                                                &p_dec->output_format );
 274
 275             if ( p_dec->p_aout_input == NULL )
 276             {
 277                 p_dec->p_fifo->b_error = 1;
 278                 break;
 279             }
 280         }
 281
 282         if ( !aout_DateGet( &end_date ) )
 283         {
 284             byte_t p_junk[MAX_FRAME_SIZE];
 285
 286             /* We've just started the stream, wait for the first PTS. */
 287             GetChunk( &p_dec->bit_stream, p_junk, i_current_frame_size );
 288             memcpy( p_sync, &p_junk[i_current_frame_size - MAD_BUFFER_GUARD],
 289                     MAD_BUFFER_GUARD );
 290             continue;
 291         }
 292
 293         p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input,
 294                                       i_frame_length );
 295         if ( p_buffer == NULL )
 296         {
 297             p_dec->p_fifo->b_error = 1;
 298             break;
 299         }
 300         p_buffer->start_date = aout_DateGet( &end_date );
 301         p_buffer->end_date = aout_DateIncrement( &end_date,
 302                                                  i_frame_length );
 303
 304         /* Get the whole frame. */
 305         memcpy( p_buffer->p_buffer, p_sync, MAD_BUFFER_GUARD );
 306         GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + MAD_BUFFER_GUARD,
 307                   i_current_frame_size - MAD_BUFFER_GUARD );
 308         if( p_dec->p_fifo->b_die )
 309         {
 310             aout_DecDeleteBuffer( p_dec->p_aout, p_dec->p_aout_input,
 311                                   p_buffer );
 312             break;
 313         }
 314         /* Get beginning of next frame. */
 315         NextPTS( &p_dec->bit_stream, &pts, NULL );
 316         GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + i_current_frame_size,
 317                   MAD_BUFFER_GUARD );
 318         memcpy( p_sync, p_buffer->p_buffer + i_current_frame_size,
 319                 MAD_BUFFER_GUARD );
 320
 321         p_buffer->i_nb_bytes = i_current_frame_size + MAD_BUFFER_GUARD;
 322
 323         /* Send the buffer to the aout core. */
 324         aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer );
 325     }
 326
 327     if( p_dec->p_fifo->b_error )
 328     {
 329         DecoderError( p_dec->p_fifo );
 330     }
 331
 332     EndThread( p_dec );
 333
 334     return 0;
 335 }
 336
 337 /*****************************************************************************
 338  * EndThread : thread destruction
 339  *****************************************************************************/
 340 static void EndThread( dec_thread_t * p_dec )
 341 {
 342     if ( p_dec->p_aout_input != NULL )
 343     {
 344         aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
 345     }
 346
 347     CloseBitstream( &p_dec->bit_stream );
 348     free( p_dec );
 349 }
 350
 351 /*****************************************************************************
 352  * SyncInfo: parse MPEG audio sync info
 353  *****************************************************************************/
 354 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
 355                      unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
 356                      unsigned int * pi_frame_length,
 357                      unsigned int * pi_frame_size, unsigned int * pi_layer )
 358 {
 359     static const int pppi_mpegaudio_bitrate[2][3][16] =
 360     {
 361         {
 362             /* v1 l1 */
 363             { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
 364               416, 448, 0},
 365             /* v1 l2 */
 366             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 160, 192, 224, 256,
 367               320, 384, 0},
 368             /* v1 l3 */
 369             { 0, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 224,
 370               256, 320, 0}
 371         },
 372
 373         {
 374             /* v2 l1 */
 375             { 0, 32, 48, 56,  64,  80,  96, 112, 128, 144, 160, 176, 192,
 376               224, 256, 0},
 377             /* v2 l2 */
 378             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 379               144, 160, 0},
 380             /* v2 l3 */
 381             { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128,
 382               144, 160, 0}
 383         }
 384     };
 385
 386     static const int ppi_mpegaudio_samplerate[2][4] = /* version 1 then 2 */
 387     {
 388         { 44100, 48000, 32000, 0 },
 389         { 22050, 24000, 16000, 0 }
 390     };
 391
 392     int i_version, i_mode, i_emphasis;
 393     vlc_bool_t b_padding, b_mpeg_2_5;
 394     int i_current_frame_size = 0;
 395     int i_bitrate_index, i_samplerate_index;
 396     int i_max_bit_rate;
 397
 398     b_mpeg_2_5  = 1 - ((i_header & 0x100000) >> 20);
 399     i_version   = 1 - ((i_header & 0x80000) >> 19);
 400     *pi_layer   = 4 - ((i_header & 0x60000) >> 17);
 401     /* CRC */
 402     i_bitrate_index = (i_header & 0xf000) >> 12;
 403     i_samplerate_index = (i_header & 0xc00) >> 10;
 404     b_padding   = (i_header & 0x200) >> 9;
 405     /* Extension */
 406     i_mode      = (i_header & 0xc0) >> 6;
 407     /* Modeext, copyright & original */
 408     i_emphasis  = i_header & 0x3;
 409
 410     if( *pi_layer != 4 &&
 411         i_bitrate_index < 0x0f &&
 412         i_samplerate_index != 0x03 &&
 413         i_emphasis != 0x02 )
 414     {
 415         switch ( i_mode )
 416         {
 417         case 0: /* stereo */
 418         case 1: /* joint stereo */
 419             *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 420             break;
 421         case 2: /* dual-mono */
 422             *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 423                             | AOUT_CHAN_DUALMONO;
 424             break;
 425         case 3: /* mono */
 426             *pi_channels = AOUT_CHAN_CENTER;
 427             break;
 428         }
 429         *pi_bit_rate = pppi_mpegaudio_bitrate[i_version][*pi_layer-1][i_bitrate_index];
 430         i_max_bit_rate = pppi_mpegaudio_bitrate[i_version][*pi_layer-1][14];
 431         *pi_sample_rate = ppi_mpegaudio_samplerate[i_version][i_samplerate_index];
 432
 433         if ( b_mpeg_2_5 )
 434         {
 435             *pi_sample_rate >>= 1;
 436         }
 437
 438         switch( *pi_layer )
 439         {
 440         case 1:
 441             i_current_frame_size = ( ( i_version ? 6000 : 12000 ) *
 442                                         *pi_bit_rate / *pi_sample_rate
 443                                         + b_padding ) * 4;
 444             *pi_frame_size = ( ( i_version ? 6000 : 12000 ) *
 445                                   i_max_bit_rate / *pi_sample_rate + 1 ) * 4;
 446             *pi_frame_length = 384;
 447             break;
 448
 449         case 2:
 450             i_current_frame_size = ( i_version ? 72000 : 144000 ) *
 451                                       *pi_bit_rate / *pi_sample_rate
 452                                       + b_padding;
 453             *pi_frame_size = ( i_version ? 72000 : 144000 ) *
 454                                       i_max_bit_rate / *pi_sample_rate + 1;
 455             *pi_frame_length = 1152;
 456             break;
 457
 458         case 3:
 459             i_current_frame_size = ( i_version ? 72000 : 144000 ) *
 460                                       *pi_bit_rate / *pi_sample_rate
 461                                       + b_padding;
 462             *pi_frame_size = ( i_version ? 72000 : 144000 ) *
 463                                       i_max_bit_rate / *pi_sample_rate + 1;
 464             *pi_frame_length = i_version ? 576 : 1152;
 465             break;
 466
 467         default:
 468             i_current_frame_size = *pi_frame_size = 0;
 469             *pi_frame_length = 0;
 470         }
 471     }
 472
 473     return i_current_frame_size;
 474 }