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_modules.h>
  39
  40 #include "a52.h"
  41
  42 /*****************************************************************************
  43  * Module descriptor
  44  *****************************************************************************/
  45 static int  OpenDecoder   ( vlc_object_t * );
  46 static int  OpenPacketizer( vlc_object_t * );
  47 static void CloseCommon   ( vlc_object_t * );
  48
  49 vlc_module_begin ()
  50     set_description( N_("A/52 parser") )
  51     set_capability( "decoder", 100 )
  52     set_callbacks( OpenDecoder, CloseCommon )
  53     set_category( CAT_INPUT )
  54     set_subcategory( SUBCAT_INPUT_ACODEC )
  55
  56     add_submodule ()
  57     set_description( N_("A/52 audio packetizer") )
  58     set_capability( "packetizer", 10 )
  59     set_callbacks( OpenPacketizer, CloseCommon )
  60 vlc_module_end ()
  61
  62 /*****************************************************************************
  63  * decoder_sys_t : decoder descriptor
  64  *****************************************************************************/
  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     date_t  end_date;
  82
  83     mtime_t i_pts;
  84
  85     vlc_a52_header_t frame;
  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 uint8_t       *GetOutBuffer ( decoder_t *, block_t ** );
 104 static aout_buffer_t *GetAoutBuffer( decoder_t * );
 105 static block_t       *GetSoutBuffer( decoder_t * );
 106
 107 /*****************************************************************************
 108  * OpenCommon: probe the decoder/packetizer and return score
 109  *****************************************************************************/
 110 static int OpenCommon( vlc_object_t *p_this, bool b_packetizer )
 111 {
 112     decoder_t *p_dec = (decoder_t*)p_this;
 113     decoder_sys_t *p_sys;
 114     vlc_fourcc_t i_codec;
 115
 116     switch( p_dec->fmt_in.i_codec )
 117     {
 118     case VLC_CODEC_A52:
 119         i_codec = VLC_CODEC_A52;
 120         break;
 121     case VLC_CODEC_EAC3:
 122         /* XXX ugly hack, a52 does not support eac3 so no eac3 pass-through
 123          * support */
 124         if( !b_packetizer )
 125             return VLC_EGENERIC;
 126         i_codec = VLC_CODEC_EAC3;
 127         break;
 128     default:
 129         return VLC_EGENERIC;
 130     }
 131
 132     /* Allocate the memory needed to store the decoder's structure */
 133     if( ( p_dec->p_sys = p_sys =
 134           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 135         return VLC_ENOMEM;
 136
 137     /* Misc init */
 138     p_sys->b_packetizer = b_packetizer;
 139     p_sys->i_state = STATE_NOSYNC;
 140     date_Set( &p_sys->end_date, 0 );
 141     p_sys->i_pts = VLC_TS_INVALID;
 142
 143     p_sys->bytestream = block_BytestreamInit();
 144
 145     /* Set output properties */
 146     p_dec->fmt_out.i_cat = AUDIO_ES;
 147     p_dec->fmt_out.i_codec = i_codec;
 148     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 149     p_dec->fmt_out.audio.i_bytes_per_frame = 0;
 150
 151     /* Set callback */
 152     if( b_packetizer )
 153         p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 154             DecodeBlock;
 155     else
 156         p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 157             DecodeBlock;
 158     return VLC_SUCCESS;
 159 }
 160
 161 static int OpenDecoder( vlc_object_t *p_this )
 162 {
 163     /* HACK: Don't use this codec if we don't have an a52 audio filter */
 164     if( !module_exists( "a52tofloat32" ) )
 165         return VLC_EGENERIC;
 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[VLC_A52_HEADER_SIZE];
 183     uint8_t *p_buf;
 184     block_t *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         date_Set( &p_sys->end_date, 0 );
 196         block_Release( *pp_block );
 197         return NULL;
 198     }
 199
 200     if( !date_Get( &p_sys->end_date ) && (*pp_block)->i_pts <= VLC_TS_INVALID)
 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 > VLC_TS_INVALID &&
 236                 p_sys->i_pts != date_Get( &p_sys->end_date ) )
 237             {
 238                 date_Set( &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 (VLC_A52_HEADER_SIZE bytes) */
 244             if( block_PeekBytes( &p_sys->bytestream, p_header,
 245                                  VLC_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             if( vlc_a52_header_Parse( &p_sys->frame, p_header, VLC_A52_HEADER_SIZE ) )
 253             {
 254                 msg_Dbg( p_dec, "emulated sync word" );
 255                 block_SkipByte( &p_sys->bytestream );
 256                 p_sys->i_state = STATE_NOSYNC;
 257                 break;
 258             }
 259
 260             p_sys->i_state = STATE_NEXT_SYNC;
 261
 262         case STATE_NEXT_SYNC:
 263             /* TODO: If pp_block == NULL, flush the buffer without checking the
 264              * next sync word */
 265
 266             /* Check if next expected frame contains the sync word */
 267             if( block_PeekOffsetBytes( &p_sys->bytestream,
 268                                        p_sys->frame.i_size, p_header, 2 )
 269                 != VLC_SUCCESS )
 270             {
 271                 /* Need more data */
 272                 return NULL;
 273             }
 274
 275             if( p_sys->b_packetizer &&
 276                 p_header[0] == 0 && p_header[1] == 0 )
 277             {
 278                 /* A52 wav files and audio CD's use stuffing */
 279                 p_sys->i_state = STATE_GET_DATA;
 280                 break;
 281             }
 282
 283             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 284             {
 285                 msg_Dbg( p_dec, "emulated sync word "
 286                          "(no sync on following frame)" );
 287                 p_sys->i_state = STATE_NOSYNC;
 288                 block_SkipByte( &p_sys->bytestream );
 289                 break;
 290             }
 291             p_sys->i_state = STATE_SEND_DATA;
 292             break;
 293
 294         case STATE_GET_DATA:
 295             /* Make sure we have enough data.
 296              * (Not useful if we went through NEXT_SYNC) */
 297             if( block_WaitBytes( &p_sys->bytestream,
 298                                  p_sys->frame.i_size ) != VLC_SUCCESS )
 299             {
 300                 /* Need more data */
 301                 return NULL;
 302             }
 303             p_sys->i_state = STATE_SEND_DATA;
 304
 305         case STATE_SEND_DATA:
 306             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 307             {
 308                 //p_dec->b_error = true;
 309                 return NULL;
 310             }
 311
 312             /* Copy the whole frame into the buffer. When we reach this point
 313              * we already know we have enough data available. */
 314             block_GetBytes( &p_sys->bytestream,
 315                             p_buf, __MIN( p_sys->frame.i_size, p_out_buffer->i_buffer ) );
 316
 317             /* Make sure we don't reuse the same pts twice */
 318             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 319                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
 320
 321             /* So p_block doesn't get re-added several times */
 322             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 323
 324             p_sys->i_state = STATE_NOSYNC;
 325
 326             return p_out_buffer;
 327         }
 328     }
 329
 330     return NULL;
 331 }
 332
 333 /*****************************************************************************
 334  * CloseCommon: clean up the decoder
 335  *****************************************************************************/
 336 static void CloseCommon( vlc_object_t *p_this )
 337 {
 338     decoder_t *p_dec = (decoder_t*)p_this;
 339     decoder_sys_t *p_sys = p_dec->p_sys;
 340
 341     block_BytestreamRelease( &p_sys->bytestream );
 342
 343     free( p_sys );
 344 }
 345
 346 /*****************************************************************************
 347  * GetOutBuffer:
 348  *****************************************************************************/
 349 static uint8_t *GetOutBuffer( decoder_t *p_dec, block_t **pp_out_buffer )
 350 {
 351     decoder_sys_t *p_sys = p_dec->p_sys;
 352     uint8_t *p_buf;
 353
 354     if( p_dec->fmt_out.audio.i_rate != p_sys->frame.i_rate )
 355     {
 356         msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 357                  p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );
 358
 359         date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );
 360         date_Set( &p_sys->end_date, p_sys->i_pts );
 361     }
 362
 363     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 364     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 365     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 366         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 367     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 368
 369     p_dec->fmt_out.audio.i_original_channels = p_sys->frame.i_channels_conf;
 370     p_dec->fmt_out.audio.i_physical_channels =
 371         p_sys->frame.i_channels_conf & AOUT_CHAN_PHYSMASK;
 372
 373     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 374
 375     if( p_sys->b_packetizer )
 376     {
 377         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 378         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 379         *pp_out_buffer = p_sout_buffer;
 380     }
 381     else
 382     {
 383         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 384         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 385         *pp_out_buffer = p_aout_buffer;
 386     }
 387
 388     return p_buf;
 389 }
 390
 391 /*****************************************************************************
 392  * GetAoutBuffer:
 393  *****************************************************************************/
 394 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 395 {
 396     decoder_sys_t *p_sys = p_dec->p_sys;
 397     aout_buffer_t *p_buf;
 398
 399     p_buf = decoder_NewAudioBuffer( p_dec, p_sys->frame.i_samples );
 400     if( p_buf == NULL ) return NULL;
 401
 402     p_buf->i_pts = date_Get( &p_sys->end_date );
 403     p_buf->i_length = date_Increment( &p_sys->end_date,
 404                                       p_sys->frame.i_samples ) - p_buf->i_pts;
 405
 406     return p_buf;
 407 }
 408
 409 /*****************************************************************************
 410  * GetSoutBuffer:
 411  *****************************************************************************/
 412 static block_t *GetSoutBuffer( decoder_t *p_dec )
 413 {
 414     decoder_sys_t *p_sys = p_dec->p_sys;
 415     block_t *p_block;
 416
 417     p_block = block_New( p_dec, p_sys->frame.i_size );
 418     if( p_block == NULL ) return NULL;
 419
 420     p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 421
 422     p_block->i_length =
 423         date_Increment( &p_sys->end_date, p_sys->frame.i_samples ) - p_block->i_pts;
 424
 425     return p_block;
 426 }
 427