git.sesse.net Git - vlc/blob - modules/demux/a52.c

   1 /*****************************************************************************
   2  * a52.c : raw A/52 stream input module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2001 VideoLAN
   5  * $Id: a52.c,v 1.2 2004/02/13 22:10:00 gbazin Exp $
   6  *
   7  * Authors: Gildas Bazin <gbazin@netcourrier.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <vlc/vlc.h>
  28 #include <vlc/input.h>
  29 #include <vlc_codec.h>
  30
  31 #ifdef HAVE_UNISTD_H
  32 #   include <unistd.h>
  33 #endif
  34
  35 #define A52_PACKET_SIZE 16384
  36 #define A52_MAX_HEADER_SIZE 10
  37
  38 /*****************************************************************************
  39  * Local prototypes
  40  *****************************************************************************/
  41 static int  Open  ( vlc_object_t * );
  42 static void Close ( vlc_object_t * );
  43 static int  Demux ( input_thread_t * );
  44
  45 static int Control( input_thread_t *, int, va_list );
  46
  47 struct demux_sys_t
  48 {
  49     vlc_bool_t  b_start;
  50     es_out_id_t *p_es;
  51
  52     /* Packetizer */
  53     decoder_t *p_packetizer;
  54
  55     int i_mux_rate;
  56     vlc_bool_t b_big_endian;
  57 };
  58
  59 /*****************************************************************************
  60  * Module descriptor
  61  *****************************************************************************/
  62 vlc_module_begin();
  63     set_description( _("Raw A/52 demuxer") );
  64     set_capability( "demux", 155 );
  65     set_callbacks( Open, Close );
  66     add_shortcut( "a52" );
  67 vlc_module_end();
  68
  69 /*****************************************************************************
  70  * CheckSync: Check if buffer starts with an A52 sync code
  71  *****************************************************************************/
  72 int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian )
  73 {
  74     /* Little endian version of the bitstream */
  75     if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
  76         p_peek[4] < 0x60 /* bsid < 12 */ )
  77     {
  78         return VLC_SUCCESS;
  79     }
  80     /* Big endian version of the bitstream */
  81     else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
  82              p_peek[5] < 0x60 /* bsid < 12 */ )
  83     {
  84         return VLC_SUCCESS;
  85     }
  86
  87     return VLC_EGENERIC;
  88 }
  89
  90 /*****************************************************************************
  91  * Open: initializes ES structures
  92  *****************************************************************************/
  93 static int Open( vlc_object_t * p_this )
  94 {
  95     input_thread_t *p_input = (input_thread_t *)p_this;
  96     demux_sys_t    *p_sys;
  97     byte_t *       p_peek;
  98     int            i_peek = 0;
  99     vlc_bool_t     b_big_endian;
 100
 101     p_input->pf_demux = Demux;
 102     p_input->pf_demux_control = Control;
 103     p_input->pf_rewind = NULL;
 104
 105     /* Check if we are dealing with a WAV file */
 106     if( input_Peek( p_input, &p_peek, 12 ) == 12 &&
 107         !strncmp( p_peek, "RIFF", 4 ) && !strncmp( &p_peek[8], "WAVE", 4 ) )
 108     {
 109         int i_size;
 110
 111         /* Skip the wave header */
 112         i_peek = 12 + 8;
 113         while( input_Peek( p_input, &p_peek, i_peek ) == i_peek &&
 114                strncmp( p_peek + i_peek - 8, "data", 4 ) )
 115         {
 116             i_peek += GetDWLE( p_peek + i_peek - 4 ) + 8;
 117         }
 118
 119         /* TODO: should check wave format and sample_rate */
 120
 121         /* Some A52 wav files don't begin with a sync code so we do a more
 122          * extensive search */
 123         i_size = input_Peek( p_input, &p_peek, i_peek + A52_PACKET_SIZE * 2);
 124         i_size -= A52_MAX_HEADER_SIZE;
 125
 126         while( i_peek < i_size )
 127         {
 128             if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
 129                 /* The data is stored in 16 bits words */
 130                 i_peek += 2;
 131             else
 132                 break;
 133         }
 134     }
 135
 136     /* Have a peep at the show. */
 137     if( input_Peek( p_input, &p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 ) <
 138         i_peek + A52_MAX_HEADER_SIZE * 2 )
 139     {
 140         /* Stream too short */
 141         msg_Warn( p_input, "cannot peek()" );
 142         return VLC_EGENERIC;
 143     }
 144
 145     if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
 146     {
 147         if( p_input->psz_demux && !strncmp( p_input->psz_demux, "a52", 3 ) )
 148         {
 149             /* User forced */
 150             msg_Err( p_input, "this doesn't look like a A52 audio stream, "
 151                      "continuing anyway" );
 152         }
 153         else
 154         {
 155             return VLC_EGENERIC;
 156         }
 157     }
 158
 159     p_input->p_demux_data = p_sys = malloc( sizeof( demux_sys_t ) );
 160     p_sys->b_start = VLC_TRUE;
 161     p_sys->i_mux_rate = 0;
 162     p_sys->b_big_endian = b_big_endian;
 163
 164     /*
 165      * Load the A52 packetizer
 166      */
 167     p_sys->p_packetizer = vlc_object_create( p_input, VLC_OBJECT_DECODER );
 168     p_sys->p_packetizer->pf_decode_audio = 0;
 169     p_sys->p_packetizer->pf_decode_video = 0;
 170     p_sys->p_packetizer->pf_decode_sub = 0;
 171     p_sys->p_packetizer->pf_packetize = 0;
 172
 173     /* Initialization of decoder structure */
 174     es_format_Init( &p_sys->p_packetizer->fmt_in, AUDIO_ES,
 175                     VLC_FOURCC( 'a', '5', '2', ' ' ) );
 176
 177     p_sys->p_packetizer->p_module =
 178         module_Need( p_sys->p_packetizer, "packetizer", NULL );
 179     if( !p_sys->p_packetizer->p_module )
 180     {
 181         msg_Err( p_input, "cannot find A52 packetizer" );
 182         return VLC_EGENERIC;
 183     }
 184
 185     /* Create one program */
 186     vlc_mutex_lock( &p_input->stream.stream_lock );
 187     if( input_InitStream( p_input, 0 ) == -1 )
 188     {
 189         vlc_mutex_unlock( &p_input->stream.stream_lock );
 190         msg_Err( p_input, "cannot init stream" );
 191         return VLC_EGENERIC;
 192     }
 193     p_input->stream.i_mux_rate = 0;
 194     vlc_mutex_unlock( &p_input->stream.stream_lock );
 195
 196     p_sys->p_es =
 197         es_out_Add( p_input->p_es_out, &p_sys->p_packetizer->fmt_in );
 198
 199     return VLC_SUCCESS;
 200 }
 201
 202 /*****************************************************************************
 203  * Close: frees unused data
 204  *****************************************************************************/
 205 static void Close( vlc_object_t * p_this )
 206 {
 207     input_thread_t *p_input = (input_thread_t*)p_this;
 208     demux_sys_t    *p_sys = p_input->p_demux_data;
 209
 210     /* Unneed module */
 211     module_Unneed( p_sys->p_packetizer, p_sys->p_packetizer->p_module );
 212
 213     /* Delete the decoder */
 214     vlc_object_destroy( p_sys->p_packetizer );
 215
 216     free( p_sys );
 217 }
 218
 219 /*****************************************************************************
 220  * Demux: reads and demuxes data packets
 221  *****************************************************************************
 222  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 223  *****************************************************************************/
 224 static int Demux( input_thread_t * p_input )
 225 {
 226     demux_sys_t  *p_sys = p_input->p_demux_data;
 227     block_t *p_block_in, *p_block_out;
 228
 229      /* Align stream */
 230     int64_t i_pos = stream_Tell( p_input->s );
 231     if( i_pos % 2 ) stream_Read( p_input->s, NULL, 1 );
 232
 233     if( !( p_block_in = stream_Block( p_input->s, A52_PACKET_SIZE ) ) )
 234     {
 235         return 0;
 236     }
 237
 238     if( !p_sys->b_big_endian && p_block_in->i_buffer )
 239     {
 240         /* Convert to big endian */
 241
 242 #ifdef HAVE_SWAB
 243         swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
 244
 245 #else
 246         int i;
 247         byte_t *p_tmp, tmp;
 248         p_tmp = p_block_in->p_buffer;
 249         for( i = p_block_in->i_buffer / 2 ; i-- ; )
 250         {
 251             tmp = p_tmp[0];
 252             p_tmp[0] = p_tmp[1];
 253             p_tmp[1] = tmp;
 254             p_tmp += 2;
 255         }
 256 #endif
 257     }
 258
 259     if( p_sys->b_start )
 260         p_block_in->i_pts = p_block_in->i_dts = 1;
 261     else
 262         p_block_in->i_pts = p_block_in->i_dts = 0;
 263
 264     while( (p_block_out = p_sys->p_packetizer->pf_packetize(
 265                 p_sys->p_packetizer, &p_block_in )) )
 266     {
 267         p_sys->b_start = VLC_FALSE;
 268
 269         while( p_block_out )
 270         {
 271             block_t *p_next = p_block_out->p_next;
 272
 273             /* We assume a constant bitrate */
 274             if( p_block_out->i_length )
 275             p_sys->i_mux_rate =
 276                 p_block_out->i_buffer * I64C(1000000) / p_block_out->i_length;
 277             p_input->stream.i_mux_rate = p_sys->i_mux_rate / 50;
 278
 279             input_ClockManageRef( p_input,
 280                                   p_input->stream.p_selected_program,
 281                                   p_block_out->i_pts * 9 / 100 );
 282
 283             p_block_in->b_discontinuity = 0;
 284             p_block_out->i_dts = p_block_out->i_pts =
 285                 input_ClockGetTS( p_input, p_input->stream.p_selected_program,
 286                                   p_block_out->i_pts * 9 / 100 );
 287
 288             es_out_Send( p_input->p_es_out, p_sys->p_es, p_block_out );
 289
 290             p_block_out = p_next;
 291         }
 292     }
 293
 294     return 1;
 295 }
 296
 297 /*****************************************************************************
 298  * Control:
 299  *****************************************************************************/
 300 static int Control( input_thread_t *p_input, int i_query, va_list args )
 301 {
 302     demux_sys_t *p_sys  = (demux_sys_t *)p_input->p_demux_data;
 303     int64_t *pi64;
 304
 305     switch( i_query )
 306     {
 307         case DEMUX_GET_TIME:
 308             pi64 = (int64_t*)va_arg( args, int64_t * );
 309             if( p_sys->i_mux_rate > 0 )
 310             {
 311                 *pi64 = I64C(1000000) * stream_Tell( p_input->s ) /
 312                         p_sys->i_mux_rate;
 313                 return VLC_SUCCESS;
 314             }
 315             *pi64 = 0;
 316             return VLC_EGENERIC;
 317
 318         case DEMUX_GET_LENGTH:
 319             pi64 = (int64_t*)va_arg( args, int64_t * );
 320             if( p_sys->i_mux_rate > 0 )
 321             {
 322                 *pi64 = I64C(1000000) * stream_Size( p_input->s ) /
 323                         p_sys->i_mux_rate;
 324                 return VLC_SUCCESS;
 325             }
 326             *pi64 = 0;
 327             return VLC_EGENERIC;
 328
 329         default:
 330             return demux_vaControlDefault( p_input, i_query, args );
 331     }
 332 }