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 <assert.h>
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_codec.h>
  38 #include <vlc_block_helper.h>
  39 #include <vlc_modules.h>
  40
  41 #include "a52.h"
  42
  43 #include "packetizer_helper.h"
  44
  45 static int  Open( vlc_object_t * );
  46 static void Close( vlc_object_t * );
  47
  48 vlc_module_begin ()
  49     set_category(CAT_SOUT)
  50     set_subcategory(SUBCAT_SOUT_PACKETIZER)
  51     set_description( N_("A/52 audio packetizer") )
  52     set_capability( "packetizer", 10 )
  53     set_callbacks( Open, Close )
  54 vlc_module_end ()
  55
  56 struct decoder_sys_t
  57 {
  58     /*
  59      * Input properties
  60      */
  61     int i_state;
  62
  63     block_bytestream_t bytestream;
  64
  65     /*
  66      * Common properties
  67      */
  68     date_t  end_date;
  69     mtime_t i_prev_bytestream_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, VLC_TS_INVALID );
  81     p_sys->i_state = STATE_NOSYNC;
  82     p_sys->i_prev_bytestream_pts = VLC_TS_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->frame.i_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_TS_INVALID )
 108     {
 109         date_Set( &p_sys->end_date, p_sys->bytestream.p_block->i_pts );
 110         p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
 111     }
 112
 113     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 114     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 115     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 116         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 117     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 118
 119     p_dec->fmt_out.audio.i_chan_mode = p_sys->frame.i_chan_mode;
 120     p_dec->fmt_out.audio.i_physical_channels = p_sys->frame.i_channels_conf;
 121
 122     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 123
 124     p_block->i_nb_samples = p_sys->frame.i_samples;
 125     p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 126     if( p_block->i_pts != VLC_TS_INVALID )
 127         p_block->i_length = date_Increment( &p_sys->end_date,
 128                                             p_block->i_nb_samples ) - p_block->i_pts;
 129
 130     return p_block;
 131 }
 132
 133 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
 134 {
 135     decoder_sys_t *p_sys = p_dec->p_sys;
 136     uint8_t p_header[VLC_A52_HEADER_SIZE];
 137     block_t *p_out_buffer;
 138
 139     block_t *p_block = pp_block ? *pp_block : NULL;
 140
 141     if( p_block )
 142     {
 143         if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
 144         {
 145             /* First always drain complete blocks before discontinuity */
 146             block_t *p_drain = PacketizeBlock( p_dec, NULL );
 147             if(p_drain)
 148                 return p_drain;
 149
 150             PacketizeFlush( p_dec );
 151
 152             if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
 153             {
 154                 block_Release( p_block );
 155                 return NULL;
 156             }
 157         }
 158
 159         /* Make sure we don't reuse the same pts twice */
 160         if( p_block->i_pts > VLC_TS_INVALID )
 161         {
 162             if( p_block->i_pts == p_sys->i_prev_bytestream_pts )
 163                 p_block->i_pts = VLC_TS_INVALID;
 164             else
 165                 p_sys->i_prev_bytestream_pts = p_block->i_pts;
 166         }
 167
 168         block_BytestreamPush( &p_sys->bytestream, p_block );
 169     }
 170
 171     while( 1 )
 172     {
 173         switch( p_sys->i_state )
 174         {
 175         case STATE_NOSYNC:
 176             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 177                    == VLC_SUCCESS )
 178             {
 179                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 180                 {
 181                     p_sys->i_state = STATE_SYNC;
 182                     break;
 183                 }
 184                 block_SkipByte( &p_sys->bytestream );
 185             }
 186             if( p_sys->i_state != STATE_SYNC )
 187             {
 188                 block_BytestreamFlush( &p_sys->bytestream );
 189
 190                 /* Need more data */
 191                 return NULL;
 192             }
 193             /* fallthrough */
 194
 195         case STATE_SYNC:
 196             p_sys->i_state = STATE_HEADER;
 197             /* fallthrough */
 198
 199         case STATE_HEADER:
 200             /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
 201             if( block_PeekBytes( &p_sys->bytestream, p_header,
 202                                  VLC_A52_HEADER_SIZE ) != VLC_SUCCESS )
 203             {
 204                 /* Need more data */
 205                 return NULL;
 206             }
 207
 208             /* Check if frame is valid and get frame info */
 209             vlc_a52_header_t a52;
 210             if( vlc_a52_header_Parse( &a52, p_header, VLC_A52_HEADER_SIZE ) )
 211             {
 212                 msg_Dbg( p_dec, "emulated sync word" );
 213                 block_SkipByte( &p_sys->bytestream );
 214                 p_sys->i_state = STATE_NOSYNC;
 215                 break;
 216             }
 217
 218             if( a52.b_eac3 && a52.eac3.strmtyp != EAC3_STRMTYP_INDEPENDENT )
 219             {
 220                 /* Use the channel configuration of the independent stream */
 221                 if( !p_sys->frame.i_blocks_per_sync_frame )
 222                 {
 223                     /* Not synced on main stream yet */
 224                     block_SkipByte( &p_sys->bytestream );
 225                     p_sys->i_state = STATE_NOSYNC;
 226                     break;
 227                 }
 228                 p_sys->frame.i_samples = a52.i_samples;
 229                 p_sys->frame.i_size = a52.i_size;
 230             }
 231             else
 232                 p_sys->frame = a52;
 233
 234             p_sys->i_state = STATE_NEXT_SYNC;
 235             /* fallthrough */
 236
 237         case STATE_NEXT_SYNC:
 238             /* Check if next expected frame contains the sync word */
 239             if( block_PeekOffsetBytes( &p_sys->bytestream,
 240                                        p_sys->frame.i_size, p_header, 2 )
 241                 != VLC_SUCCESS )
 242             {
 243                 if( p_block == NULL ) /* drain */
 244                 {
 245                     p_sys->i_state = STATE_GET_DATA;
 246                     break;
 247                 }
 248                 /* Need more data */
 249                 return NULL;
 250             }
 251
 252             if( p_header[0] == 0 && p_header[1] == 0 )
 253             {
 254                 /* A52 wav files and audio CD's use stuffing */
 255                 p_sys->i_state = STATE_GET_DATA;
 256                 break;
 257             }
 258
 259             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 260             {
 261                 msg_Dbg( p_dec, "emulated sync word "
 262                          "(no sync on following frame)" );
 263                 p_sys->i_state = STATE_NOSYNC;
 264                 block_SkipByte( &p_sys->bytestream );
 265                 break;
 266             }
 267             p_sys->i_state = STATE_GET_DATA;
 268             break;
 269
 270         case STATE_GET_DATA:
 271             /* Make sure we have enough data. */
 272             if( block_WaitBytes( &p_sys->bytestream,
 273                                  p_sys->frame.i_size ) != VLC_SUCCESS )
 274             {
 275                 /* Need more data */
 276                 return NULL;
 277             }
 278             p_sys->i_state = STATE_SEND_DATA;
 279             /* fallthrough */
 280
 281         case STATE_SEND_DATA:
 282             if( !(p_out_buffer = GetOutBuffer( p_dec )) )
 283             {
 284                 return NULL;
 285             }
 286
 287             /* Copy the whole frame into the buffer. When we reach this point
 288              * we already know we have enough data available. */
 289             block_GetBytes( &p_sys->bytestream, p_out_buffer->p_buffer,
 290                             __MIN( p_sys->frame.i_size, p_out_buffer->i_buffer ) );
 291
 292             p_sys->i_state = STATE_NOSYNC;
 293
 294             if( p_out_buffer->i_dts == VLC_TS_INVALID )
 295             {
 296                 block_Release( p_out_buffer );
 297                 return NULL;
 298             }
 299
 300             if( p_sys->b_discontuinity )
 301             {
 302                 p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY;
 303                 p_sys->b_discontuinity = false;
 304             }
 305
 306             /* So p_block doesn't get re-added several times */
 307             if( pp_block )
 308                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 309
 310             return p_out_buffer;
 311         }
 312     }
 313 }
 314
 315 static void Close( vlc_object_t *p_this )
 316 {
 317     decoder_t *p_dec = (decoder_t*)p_this;
 318     decoder_sys_t *p_sys = p_dec->p_sys;
 319
 320     block_BytestreamRelease( &p_sys->bytestream );
 321
 322     free( p_sys );
 323 }
 324
 325 static int Open( vlc_object_t *p_this )
 326 {
 327     decoder_t *p_dec = (decoder_t*)p_this;
 328     decoder_sys_t *p_sys;
 329
 330     switch( p_dec->fmt_in.i_codec )
 331     {
 332     case VLC_CODEC_EAC3:
 333     case VLC_CODEC_A52:
 334         break;
 335     default:
 336         return VLC_EGENERIC;
 337     }
 338
 339     /* Allocate the memory needed to store the decoder's structure */
 340     if( ( p_dec->p_sys = p_sys =
 341           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 342         return VLC_ENOMEM;
 343
 344     /* Misc init */
 345     p_sys->i_state = STATE_NOSYNC;
 346     date_Set( &p_sys->end_date, VLC_TS_INVALID );
 347     p_sys->b_discontuinity = false;
 348     p_sys->i_prev_bytestream_pts = VLC_TS_INVALID;
 349     memset(&p_sys->frame, 0, sizeof(vlc_a52_header_t));
 350
 351     block_BytestreamInit( &p_sys->bytestream );
 352
 353     /* Set output properties (Passthrough ONLY) */
 354     p_dec->fmt_out.i_codec = p_dec->fmt_in.i_codec;
 355     p_dec->fmt_out.audio = p_dec->fmt_in.audio;
 356     p_dec->fmt_out.audio.i_rate = 0;
 357
 358     /* Set callback */
 359     p_dec->pf_packetize = PacketizeBlock;
 360     p_dec->pf_flush     = PacketizeFlush;
 361     return VLC_SUCCESS;
 362 }