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  * $Id$
   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 it
  12  * under the terms of the GNU Lesser General Public License as published by
  13  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * 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_block_helper.h>
  37 #include <vlc_modules.h>
  38
  39 #include "a52.h"
  40
  41 #include "packetizer_helper.h"
  42
  43 static int  Open( vlc_object_t * );
  44 static void Close( vlc_object_t * );
  45
  46 vlc_module_begin ()
  47     set_category(CAT_SOUT)
  48     set_subcategory(SUBCAT_SOUT_PACKETIZER)
  49     set_description( N_("A/52 audio packetizer") )
  50     set_capability( "packetizer", 10 )
  51     set_callbacks( Open, Close )
  52 vlc_module_end ()
  53
  54 struct decoder_sys_t
  55 {
  56     /*
  57      * Input properties
  58      */
  59     int i_state;
  60
  61     block_bytestream_t bytestream;
  62
  63     /*
  64      * Common properties
  65      */
  66     date_t  end_date;
  67     bool    b_date_set;
  68
  69     mtime_t i_pts;
  70     bool    b_discontuinity;
  71
  72     vlc_a52_header_t frame;
  73 };
  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, 0 );
  81     p_sys->i_state = STATE_NOSYNC;
  82     block_BytestreamEmpty( &p_sys->bytestream );
  83 }
  84
  85 static block_t *GetOutBuffer( decoder_t *p_dec )
  86 {
  87     decoder_sys_t *p_sys = p_dec->p_sys;
  88
  89     if( !p_sys->b_date_set
  90      || p_dec->fmt_out.audio.i_rate != p_sys->frame.i_rate )
  91     {
  92         msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
  93                  p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );
  94
  95         date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );
  96         date_Set( &p_sys->end_date, p_sys->i_pts );
  97         p_sys->b_date_set = true;
  98     }
  99
 100     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 101     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 102     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 103         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 104     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 105
 106     p_dec->fmt_out.audio.i_chan_mode = p_sys->frame.i_chan_mode;
 107     p_dec->fmt_out.audio.i_physical_channels = p_sys->frame.i_channels_conf;
 108
 109     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 110
 111     block_t *p_block = block_Alloc( p_sys->frame.i_size );
 112     if( p_block == NULL )
 113         return NULL;
 114
 115     p_block->i_nb_samples = p_sys->frame.i_samples;
 116     p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 117     p_block->i_length =
 118         date_Increment( &p_sys->end_date, p_block->i_nb_samples ) - p_block->i_pts;
 119     return p_block;
 120 }
 121
 122 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
 123 {
 124     decoder_sys_t *p_sys = p_dec->p_sys;
 125     uint8_t p_header[VLC_A52_HEADER_SIZE];
 126     block_t *p_out_buffer;
 127
 128     block_t *p_block = pp_block ? *pp_block : NULL;
 129
 130     if( p_block )
 131     {
 132         if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
 133         {
 134             /* First always drain complete blocks before discontinuity */
 135             block_t *p_drain = PacketizeBlock( p_dec, NULL );
 136             if(p_drain)
 137                 return p_drain;
 138
 139             PacketizeFlush( p_dec );
 140
 141             if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
 142             {
 143                 block_Release( p_block );
 144                 return NULL;
 145             }
 146         }
 147
 148         if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TS_INVALID)
 149         {
 150             /* We've just started the stream, wait for the first PTS. */
 151             block_Release( p_block );
 152             return NULL;
 153         }
 154
 155         block_BytestreamPush( &p_sys->bytestream, p_block );
 156     }
 157
 158     while( 1 )
 159     {
 160         switch( p_sys->i_state )
 161         {
 162         case STATE_NOSYNC:
 163             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 164                    == VLC_SUCCESS )
 165             {
 166                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 167                 {
 168                     p_sys->i_state = STATE_SYNC;
 169                     break;
 170                 }
 171                 block_SkipByte( &p_sys->bytestream );
 172             }
 173             if( p_sys->i_state != STATE_SYNC )
 174             {
 175                 block_BytestreamFlush( &p_sys->bytestream );
 176
 177                 /* Need more data */
 178                 return NULL;
 179             }
 180
 181         case STATE_SYNC:
 182             /* New frame, set the Presentation Time Stamp */
 183             p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
 184             if( p_sys->i_pts > VLC_TS_INVALID &&
 185                 p_sys->i_pts != date_Get( &p_sys->end_date ) )
 186             {
 187                 date_Set( &p_sys->end_date, p_sys->i_pts );
 188             }
 189             p_sys->i_state = STATE_HEADER;
 190
 191         case STATE_HEADER:
 192             /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
 193             if( block_PeekBytes( &p_sys->bytestream, p_header,
 194                                  VLC_A52_HEADER_SIZE ) != VLC_SUCCESS )
 195             {
 196                 /* Need more data */
 197                 return NULL;
 198             }
 199
 200             /* Check if frame is valid and get frame info */
 201             vlc_a52_header_t a52;
 202             if( vlc_a52_header_Parse( &a52, p_header, VLC_A52_HEADER_SIZE ) )
 203             {
 204                 msg_Dbg( p_dec, "emulated sync word" );
 205                 block_SkipByte( &p_sys->bytestream );
 206                 p_sys->i_state = STATE_NOSYNC;
 207                 break;
 208             }
 209
 210             if( a52.b_eac3 && a52.eac3.strmtyp != EAC3_STRMTYP_INDEPENDENT )
 211             {
 212                 /* Use the channel configuration of the independent stream */
 213                 p_sys->frame.i_samples = a52.i_samples;
 214                 p_sys->frame.i_size = a52.i_size;
 215             }
 216             else
 217                 p_sys->frame = a52;
 218
 219             p_sys->i_state = STATE_NEXT_SYNC;
 220
 221         case STATE_NEXT_SYNC:
 222             /* Check if next expected frame contains the sync word */
 223             if( block_PeekOffsetBytes( &p_sys->bytestream,
 224                                        p_sys->frame.i_size, p_header, 2 )
 225                 != VLC_SUCCESS )
 226             {
 227                 if( p_block == NULL ) /* drain */
 228                 {
 229                     p_sys->i_state = STATE_GET_DATA;
 230                     break;
 231                 }
 232                 /* Need more data */
 233                 return NULL;
 234             }
 235
 236             if( p_header[0] == 0 && p_header[1] == 0 )
 237             {
 238                 /* A52 wav files and audio CD's use stuffing */
 239                 p_sys->i_state = STATE_GET_DATA;
 240                 break;
 241             }
 242
 243             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 244             {
 245                 msg_Dbg( p_dec, "emulated sync word "
 246                          "(no sync on following frame)" );
 247                 p_sys->i_state = STATE_NOSYNC;
 248                 block_SkipByte( &p_sys->bytestream );
 249                 break;
 250             }
 251             p_sys->i_state = STATE_GET_DATA;
 252             break;
 253
 254         case STATE_GET_DATA:
 255             /* Make sure we have enough data. */
 256             if( block_WaitBytes( &p_sys->bytestream,
 257                                  p_sys->frame.i_size ) != VLC_SUCCESS )
 258             {
 259                 /* Need more data */
 260                 return NULL;
 261             }
 262             p_sys->i_state = STATE_SEND_DATA;
 263
 264         case STATE_SEND_DATA:
 265             if( !(p_out_buffer = GetOutBuffer( p_dec )) )
 266             {
 267                 return NULL;
 268             }
 269
 270             /* Copy the whole frame into the buffer. When we reach this point
 271              * we already know we have enough data available. */
 272             block_GetBytes( &p_sys->bytestream, p_out_buffer->p_buffer,
 273                             __MIN( p_sys->frame.i_size, p_out_buffer->i_buffer ) );
 274
 275             /* Make sure we don't reuse the same pts twice */
 276             if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
 277                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
 278
 279             if( p_sys->b_discontuinity )
 280             {
 281                 p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY;
 282                 p_sys->b_discontuinity = false;
 283             }
 284
 285             /* So p_block doesn't get re-added several times */
 286             if( pp_block )
 287                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 288
 289             p_sys->i_state = STATE_NOSYNC;
 290
 291             return p_out_buffer;
 292         }
 293     }
 294 }
 295
 296 static void Close( vlc_object_t *p_this )
 297 {
 298     decoder_t *p_dec = (decoder_t*)p_this;
 299     decoder_sys_t *p_sys = p_dec->p_sys;
 300
 301     block_BytestreamRelease( &p_sys->bytestream );
 302
 303     free( p_sys );
 304 }
 305
 306 static int Open( vlc_object_t *p_this )
 307 {
 308     decoder_t *p_dec = (decoder_t*)p_this;
 309     decoder_sys_t *p_sys;
 310
 311     switch( p_dec->fmt_in.i_codec )
 312     {
 313     case VLC_CODEC_EAC3:
 314     case VLC_CODEC_A52:
 315         break;
 316     default:
 317         return VLC_EGENERIC;
 318     }
 319
 320     /* Allocate the memory needed to store the decoder's structure */
 321     if( ( p_dec->p_sys = p_sys =
 322           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 323         return VLC_ENOMEM;
 324
 325     /* Misc init */
 326     p_sys->i_state = STATE_NOSYNC;
 327     date_Set( &p_sys->end_date, 0 );
 328     p_sys->i_pts = VLC_TS_INVALID;
 329     p_sys->b_date_set = false;
 330     p_sys->b_discontuinity = false;
 331     memset(&p_sys->frame, 0, sizeof(vlc_a52_header_t));
 332
 333     block_BytestreamInit( &p_sys->bytestream );
 334
 335     /* Set output properties (Passthrough ONLY) */
 336     p_dec->fmt_out.i_codec = p_dec->fmt_in.i_codec;
 337     p_dec->fmt_out.audio = p_dec->fmt_in.audio;
 338
 339     /* Set callback */
 340     p_dec->pf_packetize = PacketizeBlock;
 341     p_dec->pf_flush     = PacketizeFlush;
 342     return VLC_SUCCESS;
 343 }