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 #include "../packetizer/packetizer_helper.h"
  43
  44 /*****************************************************************************
  45  * Module descriptor
  46  *****************************************************************************/
  47 static int  OpenDecoder   ( vlc_object_t * );
  48 static int  OpenPacketizer( vlc_object_t * );
  49 static void CloseCommon   ( vlc_object_t * );
  50
  51 vlc_module_begin ()
  52     set_description( N_("A/52 parser") )
  53     set_capability( "decoder", 100 )
  54     set_callbacks( OpenDecoder, CloseCommon )
  55     set_category( CAT_INPUT )
  56     set_subcategory( SUBCAT_INPUT_ACODEC )
  57
  58     add_submodule ()
  59     set_description( N_("A/52 audio packetizer") )
  60     set_capability( "packetizer", 10 )
  61     set_callbacks( OpenPacketizer, CloseCommon )
  62 vlc_module_end ()
  63
  64 /*****************************************************************************
  65  * decoder_sys_t : decoder descriptor
  66  *****************************************************************************/
  67
  68 struct decoder_sys_t
  69 {
  70     /* Module mode */
  71     bool b_packetizer;
  72
  73     /*
  74      * Input properties
  75      */
  76     int i_state;
  77
  78     block_bytestream_t bytestream;
  79
  80     /*
  81      * Common properties
  82      */
  83     date_t  end_date;
  84
  85     mtime_t i_pts;
  86
  87     vlc_a52_header_t frame;
  88 };
  89
  90 /****************************************************************************
  91  * Local prototypes
  92  ****************************************************************************/
  93 static block_t *DecodeBlock  ( decoder_t *, block_t ** );
  94
  95 static uint8_t       *GetOutBuffer ( decoder_t *, block_t ** );
  96 static aout_buffer_t *GetAoutBuffer( decoder_t * );
  97 static block_t       *GetSoutBuffer( decoder_t * );
  98
  99 /*****************************************************************************
 100  * OpenCommon: probe the decoder/packetizer and return score
 101  *****************************************************************************/
 102 static int OpenCommon( vlc_object_t *p_this, bool b_packetizer )
 103 {
 104     decoder_t *p_dec = (decoder_t*)p_this;
 105     decoder_sys_t *p_sys;
 106     vlc_fourcc_t i_codec;
 107
 108     switch( p_dec->fmt_in.i_codec )
 109     {
 110     case VLC_CODEC_A52:
 111         i_codec = VLC_CODEC_A52;
 112         break;
 113     case VLC_CODEC_EAC3:
 114         /* XXX ugly hack, a52 does not support eac3 so no eac3 pass-through
 115          * support */
 116         if( !b_packetizer )
 117             return VLC_EGENERIC;
 118         i_codec = VLC_CODEC_EAC3;
 119         break;
 120     default:
 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 = b_packetizer;
 131     p_sys->i_state = STATE_NOSYNC;
 132     date_Set( &p_sys->end_date, 0 );
 133     p_sys->i_pts = VLC_TS_INVALID;
 134
 135     block_BytestreamInit( &p_sys->bytestream );
 136
 137     /* Set output properties */
 138     p_dec->fmt_out.i_cat = AUDIO_ES;
 139     p_dec->fmt_out.i_codec = i_codec;
 140     p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
 141     p_dec->fmt_out.audio.i_bytes_per_frame = 0;
 142
 143     /* Set callback */
 144     if( b_packetizer )
 145         p_dec->pf_packetize    = DecodeBlock;
 146     else
 147         p_dec->pf_decode_audio = DecodeBlock;
 148     return VLC_SUCCESS;
 149 }
 150
 151 static int OpenDecoder( vlc_object_t *p_this )
 152 {
 153     /* HACK: Don't use this codec if we don't have an a52 audio filter */
 154     if( !module_exists( "a52tofloat32" ) )
 155         return VLC_EGENERIC;
 156     return OpenCommon( p_this, false );
 157 }
 158
 159 static int OpenPacketizer( vlc_object_t *p_this )
 160 {
 161     return OpenCommon( p_this, true );
 162 }
 163
 164 /****************************************************************************
 165  * DecodeBlock: the whole thing
 166  ****************************************************************************
 167  * This function is called just after the thread is launched.
 168  ****************************************************************************/
 169 static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 170 {
 171     decoder_sys_t *p_sys = p_dec->p_sys;
 172     uint8_t p_header[VLC_A52_HEADER_SIZE];
 173     uint8_t *p_buf;
 174     block_t *p_out_buffer;
 175
 176     if( !pp_block || !*pp_block ) return NULL;
 177
 178     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 179     {
 180         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 181         {
 182             p_sys->i_state = STATE_NOSYNC;
 183             block_BytestreamEmpty( &p_sys->bytestream );
 184         }
 185         date_Set( &p_sys->end_date, 0 );
 186         block_Release( *pp_block );
 187         return NULL;
 188     }
 189
 190     if( !date_Get( &p_sys->end_date ) && (*pp_block)->i_pts <= VLC_TS_INVALID)
 191     {
 192         /* We've just started the stream, wait for the first PTS. */
 193         block_Release( *pp_block );
 194         return NULL;
 195     }
 196
 197     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 198
 199     while( 1 )
 200     {
 201         switch( p_sys->i_state )
 202         {
 203         case STATE_NOSYNC:
 204             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 205                    == VLC_SUCCESS )
 206             {
 207                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 208                 {
 209                     p_sys->i_state = STATE_SYNC;
 210                     break;
 211                 }
 212                 block_SkipByte( &p_sys->bytestream );
 213             }
 214             if( p_sys->i_state != STATE_SYNC )
 215             {
 216                 block_BytestreamFlush( &p_sys->bytestream );
 217
 218                 /* Need more data */
 219                 return NULL;
 220             }
 221
 222         case STATE_SYNC:
 223             /* New frame, set the Presentation Time Stamp */
 224             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 225             if( p_sys->i_pts > VLC_TS_INVALID &&
 226                 p_sys->i_pts != date_Get( &p_sys->end_date ) )
 227             {
 228                 date_Set( &p_sys->end_date, p_sys->i_pts );
 229             }
 230             p_sys->i_state = STATE_HEADER;
 231
 232         case STATE_HEADER:
 233             /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
 234             if( block_PeekBytes( &p_sys->bytestream, p_header,
 235                                  VLC_A52_HEADER_SIZE ) != VLC_SUCCESS )
 236             {
 237                 /* Need more data */
 238                 return NULL;
 239             }
 240
 241             /* Check if frame is valid and get frame info */
 242             if( vlc_a52_header_Parse( &p_sys->frame, p_header, VLC_A52_HEADER_SIZE ) )
 243             {
 244                 msg_Dbg( p_dec, "emulated sync word" );
 245                 block_SkipByte( &p_sys->bytestream );
 246                 p_sys->i_state = STATE_NOSYNC;
 247                 break;
 248             }
 249
 250             p_sys->i_state = STATE_NEXT_SYNC;
 251
 252         case STATE_NEXT_SYNC:
 253             /* TODO: If pp_block == NULL, flush the buffer without checking the
 254              * next sync word */
 255
 256             /* Check if next expected frame contains the sync word */
 257             if( block_PeekOffsetBytes( &p_sys->bytestream,
 258                                        p_sys->frame.i_size, p_header, 2 )
 259                 != VLC_SUCCESS )
 260             {
 261                 /* Need more data */
 262                 return NULL;
 263             }
 264
 265             if( p_sys->b_packetizer &&
 266                 p_header[0] == 0 && p_header[1] == 0 )
 267             {
 268                 /* A52 wav files and audio CD's use stuffing */
 269                 p_sys->i_state = STATE_GET_DATA;
 270                 break;
 271             }
 272
 273             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 274             {
 275                 msg_Dbg( p_dec, "emulated sync word "
 276                          "(no sync on following frame)" );
 277                 p_sys->i_state = STATE_NOSYNC;
 278                 block_SkipByte( &p_sys->bytestream );
 279                 break;
 280             }
 281             p_sys->i_state = STATE_SEND_DATA;
 282             break;
 283
 284         case STATE_GET_DATA:
 285             /* Make sure we have enough data.
 286              * (Not useful if we went through NEXT_SYNC) */
 287             if( block_WaitBytes( &p_sys->bytestream,
 288                                  p_sys->frame.i_size ) != VLC_SUCCESS )
 289             {
 290                 /* Need more data */
 291                 return NULL;
 292             }
 293             p_sys->i_state = STATE_SEND_DATA;
 294
 295         case STATE_SEND_DATA:
 296             if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
 297             {
 298                 //p_dec->b_error = true;
 299                 return NULL;
 300             }
 301
 302             /* Copy the whole frame into the buffer. When we reach this point
 303              * we already know we have enough data available. */
 304             block_GetBytes( &p_sys->bytestream,
 305                             p_buf, __MIN( p_sys->frame.i_size, p_out_buffer->i_buffer ) );
 306
 307             /* Make sure we don't reuse the same pts twice */
 308             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 309                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
 310
 311             /* So p_block doesn't get re-added several times */
 312             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 313
 314             p_sys->i_state = STATE_NOSYNC;
 315
 316             return p_out_buffer;
 317         }
 318     }
 319 }
 320
 321 /*****************************************************************************
 322  * CloseCommon: clean up the decoder
 323  *****************************************************************************/
 324 static void CloseCommon( vlc_object_t *p_this )
 325 {
 326     decoder_t *p_dec = (decoder_t*)p_this;
 327     decoder_sys_t *p_sys = p_dec->p_sys;
 328
 329     block_BytestreamRelease( &p_sys->bytestream );
 330
 331     free( p_sys );
 332 }
 333
 334 /*****************************************************************************
 335  * GetOutBuffer:
 336  *****************************************************************************/
 337 static uint8_t *GetOutBuffer( decoder_t *p_dec, block_t **pp_out_buffer )
 338 {
 339     decoder_sys_t *p_sys = p_dec->p_sys;
 340     uint8_t *p_buf;
 341
 342     if( p_dec->fmt_out.audio.i_rate != p_sys->frame.i_rate )
 343     {
 344         msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
 345                  p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );
 346
 347         date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );
 348         date_Set( &p_sys->end_date, p_sys->i_pts );
 349     }
 350
 351     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 352     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 353     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 354         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 355     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 356
 357     p_dec->fmt_out.audio.i_original_channels = p_sys->frame.i_channels_conf;
 358     p_dec->fmt_out.audio.i_physical_channels =
 359         p_sys->frame.i_channels_conf & AOUT_CHAN_PHYSMASK;
 360
 361     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 362
 363     if( p_sys->b_packetizer )
 364     {
 365         block_t *p_sout_buffer = GetSoutBuffer( p_dec );
 366         p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
 367         *pp_out_buffer = p_sout_buffer;
 368     }
 369     else
 370     {
 371         aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
 372         p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
 373         *pp_out_buffer = p_aout_buffer;
 374     }
 375
 376     return p_buf;
 377 }
 378
 379 /*****************************************************************************
 380  * GetAoutBuffer:
 381  *****************************************************************************/
 382 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
 383 {
 384     decoder_sys_t *p_sys = p_dec->p_sys;
 385
 386     aout_buffer_t *p_buf = decoder_NewAudioBuffer( p_dec, p_sys->frame.i_samples );
 387     if( p_buf )
 388     {
 389         p_buf->i_pts = date_Get( &p_sys->end_date );
 390         p_buf->i_length = date_Increment( &p_sys->end_date,
 391                                           p_sys->frame.i_samples ) - p_buf->i_pts;
 392     }
 393
 394     return p_buf;
 395 }
 396
 397 /*****************************************************************************
 398  * GetSoutBuffer:
 399  *****************************************************************************/
 400 static block_t *GetSoutBuffer( decoder_t *p_dec )
 401 {
 402     decoder_sys_t *p_sys = p_dec->p_sys;
 403
 404     block_t *p_block = block_New( p_dec, p_sys->frame.i_size );
 405     if( p_block )
 406     {
 407         p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 408         p_block->i_length =
 409             date_Increment( &p_sys->end_date, p_sys->frame.i_samples ) - p_block->i_pts;
 410     }
 411
 412     return p_block;
 413 }
 414