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             date_Set( &p_sys->end_date, p_sys->bytestream.p_block->i_pts );
 113         p_sys->i_prev_bytestream_pts = p_sys->bytestream.p_block->i_pts;
 114         p_sys->bytestream.p_block->i_pts = VLC_TICK_INVALID;
 115     }
 116
 117     p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;
 118     p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
 119     if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
 120         p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
 121     p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
 122
 123     p_dec->fmt_out.audio.i_chan_mode = p_sys->frame.i_chan_mode;
 124     p_dec->fmt_out.audio.i_physical_channels = p_sys->frame.i_channels_conf;
 125
 126     p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
 127
 128     p_block->i_nb_samples = p_sys->frame.i_samples;
 129     p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
 130     if( p_block->i_pts != VLC_TICK_INVALID )
 131         p_block->i_length = date_Increment( &p_sys->end_date,
 132                                             p_block->i_nb_samples ) - p_block->i_pts;
 133
 134     return p_block;
 135 }
 136
 137 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
 138 {
 139     decoder_sys_t *p_sys = p_dec->p_sys;
 140     uint8_t p_header[VLC_A52_MIN_HEADER_SIZE];
 141     block_t *p_out_buffer;
 142
 143     block_t *p_block = pp_block ? *pp_block : NULL;
 144
 145     if( p_block )
 146     {
 147         if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
 148         {
 149             /* First always drain complete blocks before discontinuity */
 150             block_t *p_drain = PacketizeBlock( p_dec, NULL );
 151             if(p_drain)
 152                 return p_drain;
 153
 154             PacketizeFlush( p_dec );
 155
 156             if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
 157             {
 158                 block_Release( p_block );
 159                 return NULL;
 160             }
 161         }
 162
 163         block_BytestreamPush( &p_sys->bytestream, p_block );
 164     }
 165
 166     while( 1 )
 167     {
 168         switch( p_sys->i_state )
 169         {
 170         case STATE_NOSYNC:
 171             while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
 172                    == VLC_SUCCESS )
 173             {
 174                 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
 175                 {
 176                     p_sys->i_state = STATE_SYNC;
 177                     break;
 178                 }
 179                 block_SkipByte( &p_sys->bytestream );
 180             }
 181             if( p_sys->i_state != STATE_SYNC )
 182             {
 183                 block_BytestreamFlush( &p_sys->bytestream );
 184
 185                 /* Need more data */
 186                 return NULL;
 187             }
 188             /* fallthrough */
 189
 190         case STATE_SYNC:
 191             p_sys->i_state = STATE_HEADER;
 192             /* fallthrough */
 193
 194         case STATE_HEADER:
 195             /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
 196             if( block_PeekBytes( &p_sys->bytestream, p_header,
 197                                  VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )
 198             {
 199                 /* Need more data */
 200                 return NULL;
 201             }
 202
 203             /* Check if frame is valid and get frame info */
 204             if( vlc_a52_header_Parse( &p_sys->frame, p_header,
 205                                       VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )
 206             {
 207                 msg_Dbg( p_dec, "emulated sync word" );
 208                 block_SkipByte( &p_sys->bytestream );
 209                 p_sys->i_state = STATE_NOSYNC;
 210                 break;
 211             }
 212
 213             if( p_sys->frame.b_eac3 && p_sys->frame.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )
 214             {
 215                 msg_Warn( p_dec, "starting with dependent stream, skip it" );
 216                 p_sys->i_state = STATE_NOSYNC;
 217                 if( block_SkipBytes( &p_sys->bytestream,
 218                                      p_sys->frame.i_size ) != VLC_SUCCESS )
 219                     return NULL;
 220                 break;
 221             }
 222
 223             p_sys->i_input_size = p_sys->frame.i_size;
 224             p_sys->i_state = STATE_NEXT_SYNC;
 225             /* fallthrough */
 226
 227         case STATE_NEXT_SYNC:
 228             /* Check if next expected frame contains the sync word */
 229             if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_input_size,
 230                                        p_header, VLC_A52_MIN_HEADER_SIZE )
 231                                        != VLC_SUCCESS )
 232             {
 233                 if( p_block == NULL ) /* drain */
 234                 {
 235                     p_sys->i_state = STATE_GET_DATA;
 236                     break;
 237                 }
 238                 /* Need more data */
 239                 return NULL;
 240             }
 241
 242             if( p_header[0] == 0 || p_header[1] == 0 )
 243             {
 244                 /* A52 wav files and audio CD's use stuffing */
 245                 p_sys->i_state = STATE_GET_DATA;
 246                 break;
 247             }
 248
 249             if( p_header[0] != 0x0b || p_header[1] != 0x77 )
 250             {
 251                 msg_Dbg( p_dec, "emulated sync word "
 252                          "(no sync on following frame)" );
 253                 p_sys->i_state = STATE_NOSYNC;
 254                 block_SkipByte( &p_sys->bytestream );
 255                 break;
 256             }
 257
 258             vlc_a52_header_t a52;
 259             if( !vlc_a52_header_Parse( &a52, p_header, VLC_A52_MIN_HEADER_SIZE )
 260              && a52.b_eac3 && a52.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )
 261             {
 262                 p_sys->i_input_size += a52.i_size;
 263                 p_dec->fmt_out.i_codec = VLC_CODEC_A52;
 264                 p_dec->fmt_out.i_profile = VLC_A52_PROFILE_EAC3_DEPENDENT;
 265             }
 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->i_input_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                             p_out_buffer->i_buffer );
 291
 292             p_sys->i_state = STATE_NOSYNC;
 293
 294             if( p_out_buffer->i_dts == VLC_TICK_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_TICK_INVALID );
 347     p_sys->b_discontuinity = false;
 348     p_sys->i_prev_bytestream_pts = VLC_TICK_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     p_dec->pf_get_cc    = NULL;
 362     return VLC_SUCCESS;
 363 }