modules/packetizer/a52.c

   1 /*****************************************************************************
   2  * a52.c: parse A/52 audio sync info and packetize the stream
   3  *****************************************************************************
   4  * Copyright (C) 2001-2016 VLC authors and VideoLAN
   5  *
   6  * Authors: Stéphane Borel <stef@via.ecp.fr>
   7  *          Christophe Massiot <massiot@via.ecp.fr>
   8  *          Gildas Bazin <gbazin@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <assert.h>
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_codec.h>
  37 #include <vlc_block_helper.h>
  38 #include <vlc_modules.h>
  39
  40 #include "a52.h"
  41
  42 #include "packetizer_helper.h"
  43
  44 static int  Open( vlc_object_t * );
  45 static void Close( vlc_object_t * );
  46
  47 vlc_module_begin ()
  48     set_category(CAT_SOUT)
  49     set_subcategory(SUBCAT_SOUT_PACKETIZER)
  50     set_description( N_("A/52 audio packetizer") )
  51     set_capability( "packetizer", 10 )
  52     set_callbacks( Open, Close )
  53 vlc_module_end ()
  54
  55 typedef struct
  56 {
  57     /*
  58      * Input properties
  59      */
  60     int i_state;
  61
  62     block_bytestream_t bytestream;
  63
  64     /*
  65      * Common properties
  66      */
  67     date_t  end_date;
  68     vlc_tick_t i_prev_bytestream_pts;
  69     bool    b_discontuinity;
  70
  71     vlc_a52_header_t frame;
  72     size_t  i_input_size;
  73 } decoder_sys_t;
  74
  75 static void PacketizeFlush( decoder_t *p_dec )
  76 {
  77     decoder_sys_t *p_sys = p_dec->p_sys;
  78
  79     p_sys->b_discontuinity = true;
  80     date_Set( &p_sys->end_date, VLC_TICK_INVALID );
  81     p_sys->i_state = STATE_NOSYNC;
  82     p_sys->i_prev_bytestream_pts = VLC_TICK_INVALID;
  83     block_BytestreamEmpty( &p_sys->bytestream );
  84 }
  85
  86 static block_t *GetOutBuffer( decoder_t *p_dec )
  87 {
  88     decoder_sys_t *p_sys = p_dec->p_sys;
  89
  90     assert( p_sys->frame.i_rate > 0 );
  91
  92     block_t *p_block = block_Alloc( p_sys->i_input_size );
  93     if( p_block == NULL )
  94         return NULL;
  95
  96     if( p_dec->fmt_out.audio.i_rate != p_sys->frame.i_rate )
  97     {
  98         msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
  99                  p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );
 100         if( p_sys->end_date.i_divider_num )
 101             date_Change( &p_sys->end_date, p_sys->frame.i_rate, 1 );
 102         else
 103             date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );
 104     }
 105
 106     if( p_sys->bytestream.p_block->i_pts != date_Get( &p_sys->end_date ) &&
 107         p_sys->bytestream.p_block->i_pts != VLC_TICK_INVALID )
 108     {
 109         /* Make sure we don't reuse the same pts twice
 110          * as A/52 in PES sends multiple times the same pts */
 111         if( p_sys->bytestream.p_block->i_pts != p_sys->i_prev_bytestream_pts )
 112         {
 113             date_t tempdate = p_sys->end_date;
 114             date_Increment( &tempdate, p_sys->frame.i_samples );
 115             vlc_tick_t samplesduration = date_Get( &tempdate ) - date_Get( &p_sys->end_date );
 116             if( llabs(p_sys->bytestream.p_block->i_pts  - date_Get( &p_sys->end_date )) > samplesduration )
 117                 date_Set( &p_sys->end_date, p_sys->bytestream.p_block->i_pts );
 118             p_sys->i_prev_bytestream_pts = p_sys->bytestream.p_block->i_pts;
 119             p_sys->bytestream.p_block->i_pts = VLC_TICK_INVALID;
 120         }
 121     }
 122
 123     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 124     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 125     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 126         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 127     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 128
 129     p_dec->fmt_out.audio.i_chan_mode = p_sys->frame.i_chan_mode;
 130     p_dec->fmt_out.audio.i_physical_channels = p_sys->frame.i_channels_conf;
 131
 132     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 133
 134     p_block->i_nb_samples = p_sys->frame.i_samples;
 135     p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 136     if( p_block->i_pts != VLC_TICK_INVALID )
 137         p_block->i_length = date_Increment( &p_sys->end_date,
 138                                             p_block->i_nb_samples ) - p_block->i_pts;
 139
 140     return p_block;
 141 }
 142
 143 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
 144 {
 145     decoder_sys_t *p_sys = p_dec->p_sys;
 146     uint8_t p_header[VLC_A52_MIN_HEADER_SIZE];
 147     block_t *p_out_buffer;
 148
 149     block_t *p_block = pp_block ? *pp_block : NULL;
 150
 151     if( p_block )
 152     {
 153         if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
 154         {
 155             /* First always drain complete blocks before discontinuity */
 156             block_t *p_drain = PacketizeBlock( p_dec, NULL );
 157             if(p_drain)
 158                 return p_drain;
 159
 160             PacketizeFlush( p_dec );
 161
 162             if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
 163             {
 164                 block_Release( p_block );
 165                 return NULL;
 166             }
 167         }
 168
 169         block_BytestreamPush( &p_sys->bytestream, p_block );
 170     }
 171
 172     while( 1 )
 173     {
 174         switch( p_sys->i_state )
 175         {
 176         case STATE_NOSYNC:
 177             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 178                    == VLC_SUCCESS )
 179             {
 180                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 181                 {
 182                     p_sys->i_state = STATE_SYNC;
 183                     break;
 184                 }
 185                 block_SkipByte( &p_sys->bytestream );
 186             }
 187             if( p_sys->i_state != STATE_SYNC )
 188             {
 189                 block_BytestreamFlush( &p_sys->bytestream );
 190
 191                 /* Need more data */
 192                 return NULL;
 193             }
 194             /* fallthrough */
 195
 196         case STATE_SYNC:
 197             p_sys->i_state = STATE_HEADER;
 198             /* fallthrough */
 199
 200         case STATE_HEADER:
 201             /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
 202             if( block_PeekBytes( &p_sys->bytestream, p_header,
 203                                  VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )
 204             {
 205                 /* Need more data */
 206                 return NULL;
 207             }
 208
 209             /* Check if frame is valid and get frame info */
 210             if( vlc_a52_header_Parse( &p_sys->frame, p_header,
 211                                       VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )
 212             {
 213                 msg_Dbg( p_dec, "emulated sync word" );
 214                 block_SkipByte( &p_sys->bytestream );
 215                 p_sys->i_state = STATE_NOSYNC;
 216                 break;
 217             }
 218
 219             if( p_sys->frame.b_eac3 && p_sys->frame.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )
 220             {
 221                 msg_Warn( p_dec, "starting with dependent stream, skip it" );
 222                 p_sys->i_state = STATE_NOSYNC;
 223                 if( block_SkipBytes( &p_sys->bytestream,
 224                                      p_sys->frame.i_size ) != VLC_SUCCESS )
 225                     return NULL;
 226                 break;
 227             }
 228
 229             p_sys->i_input_size = p_sys->frame.i_size;
 230             p_sys->i_state = STATE_NEXT_SYNC;
 231             /* fallthrough */
 232
 233         case STATE_NEXT_SYNC:
 234             /* Check if next expected frame contains the sync word */
 235             if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_input_size,
 236                                        p_header, VLC_A52_MIN_HEADER_SIZE )
 237                                        != VLC_SUCCESS )
 238             {
 239                 if( p_block == NULL ) /* drain */
 240                 {
 241                     p_sys->i_state = STATE_GET_DATA;
 242                     break;
 243                 }
 244                 /* Need more data */
 245                 return NULL;
 246             }
 247
 248             if( p_header[0] == 0 || p_header[1] == 0 )
 249             {
 250                 /* A52 wav files and audio CD's use stuffing */
 251                 p_sys->i_state = STATE_GET_DATA;
 252                 break;
 253             }
 254
 255             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 256             {
 257                 msg_Dbg( p_dec, "emulated sync word "
 258                          "(no sync on following frame)" );
 259                 p_sys->i_state = STATE_NOSYNC;
 260                 block_SkipByte( &p_sys->bytestream );
 261                 break;
 262             }
 263
 264             vlc_a52_header_t a52;
 265             if( !vlc_a52_header_Parse( &a52, p_header, VLC_A52_MIN_HEADER_SIZE )
 266              && a52.b_eac3 && a52.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )
 267             {
 268                 p_sys->i_input_size += a52.i_size;
 269                 p_dec->fmt_out.i_codec = VLC_CODEC_A52;
 270                 p_dec->fmt_out.i_profile = VLC_A52_PROFILE_EAC3_DEPENDENT;
 271             }
 272
 273             p_sys->i_state = STATE_GET_DATA;
 274             break;
 275
 276         case STATE_GET_DATA:
 277             /* Make sure we have enough data. */
 278             if( block_WaitBytes( &p_sys->bytestream,
 279                                  p_sys->i_input_size ) != VLC_SUCCESS )
 280             {
 281                 /* Need more data */
 282                 return NULL;
 283             }
 284             p_sys->i_state = STATE_SEND_DATA;
 285             /* fallthrough */
 286
 287         case STATE_SEND_DATA:
 288             if( !(p_out_buffer = GetOutBuffer( p_dec )) )
 289             {
 290                 return NULL;
 291             }
 292
 293             /* Copy the whole frame into the buffer. When we reach this point
 294              * we already know we have enough data available. */
 295             block_GetBytes( &p_sys->bytestream, p_out_buffer->p_buffer,
 296                             p_out_buffer->i_buffer );
 297
 298             p_sys->i_state = STATE_NOSYNC;
 299
 300             if( p_out_buffer->i_dts == VLC_TICK_INVALID )
 301             {
 302                 block_Release( p_out_buffer );
 303                 return NULL;
 304             }
 305
 306             if( p_sys->b_discontuinity )
 307             {
 308                 p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY;
 309                 p_sys->b_discontuinity = false;
 310             }
 311
 312             /* So p_block doesn't get re-added several times */
 313             if( pp_block )
 314                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 315
 316             return p_out_buffer;
 317         }
 318     }
 319 }
 320
 321 static void Close( vlc_object_t *p_this )
 322 {
 323     decoder_t *p_dec = (decoder_t*)p_this;
 324     decoder_sys_t *p_sys = p_dec->p_sys;
 325
 326     block_BytestreamRelease( &p_sys->bytestream );
 327
 328     free( p_sys );
 329 }
 330
 331 static int Open( vlc_object_t *p_this )
 332 {
 333     decoder_t *p_dec = (decoder_t*)p_this;
 334     decoder_sys_t *p_sys;
 335
 336     switch( p_dec->fmt_in.i_codec )
 337     {
 338     case VLC_CODEC_EAC3:
 339     case VLC_CODEC_A52:
 340         break;
 341     default:
 342         return VLC_EGENERIC;
 343     }
 344
 345     /* Allocate the memory needed to store the decoder's structure */
 346     if( ( p_dec->p_sys = p_sys =
 347           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 348         return VLC_ENOMEM;
 349
 350     /* Misc init */
 351     p_sys->i_state = STATE_NOSYNC;
 352     date_Set( &p_sys->end_date, VLC_TICK_INVALID );
 353     p_sys->b_discontuinity = false;
 354     p_sys->i_prev_bytestream_pts = VLC_TICK_INVALID;
 355     memset(&p_sys->frame, 0, sizeof(vlc_a52_header_t));
 356
 357     block_BytestreamInit( &p_sys->bytestream );
 358
 359     /* Set output properties (Passthrough ONLY) */
 360     p_dec->fmt_out.i_codec = p_dec->fmt_in.i_codec;
 361     p_dec->fmt_out.audio = p_dec->fmt_in.audio;
 362     p_dec->fmt_out.audio.i_rate = 0;
 363
 364     /* Set callback */
 365     p_dec->pf_packetize = PacketizeBlock;
 366     p_dec->pf_flush     = PacketizeFlush;
 367     p_dec->pf_get_cc    = NULL;
 368     return VLC_SUCCESS;
 369 }