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 1.4 2004/02/13 22:37:35 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 PCM_FRAME_SIZE (1536 * 4)
  36 #define A52_PACKET_SIZE (4 * PCM_FRAME_SIZE)
  37 #define A52_MAX_HEADER_SIZE 10
  38
  39 /*****************************************************************************
  40  * Local prototypes
  41  *****************************************************************************/
  42 static int  Open  ( vlc_object_t * );
  43 static void Close ( vlc_object_t * );
  44 static int  Demux ( input_thread_t * );
  45
  46 static int Control( input_thread_t *, int, va_list );
  47
  48 struct demux_sys_t
  49 {
  50     vlc_bool_t  b_start;
  51     es_out_id_t *p_es;
  52
  53     /* Packetizer */
  54     decoder_t *p_packetizer;
  55
  56     int i_mux_rate;
  57     vlc_bool_t b_big_endian;
  58 };
  59
  60 /*****************************************************************************
  61  * Module descriptor
  62  *****************************************************************************/
  63 vlc_module_begin();
  64     set_description( _("Raw A/52 demuxer") );
  65     set_capability( "demux", 145 );
  66     set_callbacks( Open, Close );
  67     add_shortcut( "a52" );
  68 vlc_module_end();
  69
  70 /*****************************************************************************
  71  * CheckSync: Check if buffer starts with an A52 sync code
  72  *****************************************************************************/
  73 int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian )
  74 {
  75     /* Little endian version of the bitstream */
  76     if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
  77         p_peek[4] < 0x60 /* bsid < 12 */ )
  78     {
  79         *p_big_endian = VLC_FALSE;
  80         return VLC_SUCCESS;
  81     }
  82     /* Big endian version of the bitstream */
  83     else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
  84              p_peek[5] < 0x60 /* bsid < 12 */ )
  85     {
  86         *p_big_endian = VLC_TRUE;
  87         return VLC_SUCCESS;
  88     }
  89
  90     return VLC_EGENERIC;
  91 }
  92
  93 /*****************************************************************************
  94  * Open: initializes ES structures
  95  *****************************************************************************/
  96 static int Open( vlc_object_t * p_this )
  97 {
  98     input_thread_t *p_input = (input_thread_t *)p_this;
  99     demux_sys_t    *p_sys;
 100     byte_t *       p_peek;
 101     int            i_peek = 0;
 102     vlc_bool_t     b_big_endian;
 103
 104     p_input->pf_demux = Demux;
 105     p_input->pf_demux_control = Control;
 106     p_input->pf_rewind = NULL;
 107
 108     /* Check if we are dealing with a WAV file */
 109     if( input_Peek( p_input, &p_peek, 12 ) == 12 &&
 110         !strncmp( p_peek, "RIFF", 4 ) && !strncmp( &p_peek[8], "WAVE", 4 ) )
 111     {
 112         int i_size;
 113
 114         /* Skip the wave header */
 115         i_peek = 12 + 8;
 116         while( input_Peek( p_input, &p_peek, i_peek ) == i_peek &&
 117                strncmp( p_peek + i_peek - 8, "data", 4 ) )
 118         {
 119             i_peek += GetDWLE( p_peek + i_peek - 4 ) + 8;
 120         }
 121
 122         /* TODO: should check wave format and sample_rate */
 123
 124         /* Some A52 wav files don't begin with a sync code so we do a more
 125          * extensive search */
 126         i_size = input_Peek( p_input, &p_peek, i_peek + A52_PACKET_SIZE * 2);
 127         i_size -= (PCM_FRAME_SIZE + A52_MAX_HEADER_SIZE);
 128
 129         while( i_peek < i_size )
 130         {
 131             if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
 132                 /* The data is stored in 16 bits words */
 133                 i_peek += 2;
 134             else
 135             {
 136                 /* Check following sync code */
 137                 if( CheckSync( p_peek + i_peek + PCM_FRAME_SIZE,
 138                                &b_big_endian ) != VLC_SUCCESS )
 139                 {
 140                     i_peek += 2;
 141                     continue;
 142                 }
 143
 144                 break;
 145             }
 146         }
 147     }
 148
 149     /* Have a peep at the show. */
 150     if( input_Peek( p_input, &p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 ) <
 151         i_peek + A52_MAX_HEADER_SIZE * 2 )
 152     {
 153         /* Stream too short */
 154         msg_Warn( p_input, "cannot peek()" );
 155         return VLC_EGENERIC;
 156     }
 157
 158     if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
 159     {
 160         if( p_input->psz_demux && !strncmp( p_input->psz_demux, "a52", 3 ) )
 161         {
 162             /* User forced */
 163             msg_Err( p_input, "this doesn't look like a A52 audio stream, "
 164                      "continuing anyway" );
 165         }
 166         else
 167         {
 168             return VLC_EGENERIC;
 169         }
 170     }
 171
 172     p_input->p_demux_data = p_sys = malloc( sizeof( demux_sys_t ) );
 173     p_sys->b_start = VLC_TRUE;
 174     p_sys->i_mux_rate = 0;
 175     p_sys->b_big_endian = b_big_endian;
 176
 177     /*
 178      * Load the A52 packetizer
 179      */
 180     p_sys->p_packetizer = vlc_object_create( p_input, VLC_OBJECT_DECODER );
 181     p_sys->p_packetizer->pf_decode_audio = 0;
 182     p_sys->p_packetizer->pf_decode_video = 0;
 183     p_sys->p_packetizer->pf_decode_sub = 0;
 184     p_sys->p_packetizer->pf_packetize = 0;
 185
 186     /* Initialization of decoder structure */
 187     es_format_Init( &p_sys->p_packetizer->fmt_in, AUDIO_ES,
 188                     VLC_FOURCC( 'a', '5', '2', ' ' ) );
 189
 190     p_sys->p_packetizer->p_module =
 191         module_Need( p_sys->p_packetizer, "packetizer", NULL );
 192     if( !p_sys->p_packetizer->p_module )
 193     {
 194         msg_Err( p_input, "cannot find A52 packetizer" );
 195         return VLC_EGENERIC;
 196     }
 197
 198     /* Create one program */
 199     vlc_mutex_lock( &p_input->stream.stream_lock );
 200     if( input_InitStream( p_input, 0 ) == -1 )
 201     {
 202         vlc_mutex_unlock( &p_input->stream.stream_lock );
 203         msg_Err( p_input, "cannot init stream" );
 204         return VLC_EGENERIC;
 205     }
 206     p_input->stream.i_mux_rate = 0;
 207     vlc_mutex_unlock( &p_input->stream.stream_lock );
 208
 209     p_sys->p_es =
 210         es_out_Add( p_input->p_es_out, &p_sys->p_packetizer->fmt_in );
 211
 212     return VLC_SUCCESS;
 213 }
 214
 215 /*****************************************************************************
 216  * Close: frees unused data
 217  *****************************************************************************/
 218 static void Close( vlc_object_t * p_this )
 219 {
 220     input_thread_t *p_input = (input_thread_t*)p_this;
 221     demux_sys_t    *p_sys = p_input->p_demux_data;
 222
 223     /* Unneed module */
 224     module_Unneed( p_sys->p_packetizer, p_sys->p_packetizer->p_module );
 225
 226     /* Delete the decoder */
 227     vlc_object_destroy( p_sys->p_packetizer );
 228
 229     free( p_sys );
 230 }
 231
 232 /*****************************************************************************
 233  * Demux: reads and demuxes data packets
 234  *****************************************************************************
 235  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 236  *****************************************************************************/
 237 static int Demux( input_thread_t * p_input )
 238 {
 239     demux_sys_t  *p_sys = p_input->p_demux_data;
 240     block_t *p_block_in, *p_block_out;
 241
 242      /* Align stream */
 243     int64_t i_pos = stream_Tell( p_input->s );
 244     if( i_pos % 2 ) stream_Read( p_input->s, NULL, 1 );
 245
 246     if( !( p_block_in = stream_Block( p_input->s, A52_PACKET_SIZE ) ) )
 247     {
 248         return 0;
 249     }
 250
 251     if( !p_sys->b_big_endian && p_block_in->i_buffer )
 252     {
 253         /* Convert to big endian */
 254
 255 #ifdef HAVE_SWAB
 256         swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
 257
 258 #else
 259         int i;
 260         byte_t *p_tmp, tmp;
 261         p_tmp = p_block_in->p_buffer;
 262         for( i = p_block_in->i_buffer / 2 ; i-- ; )
 263         {
 264             tmp = p_tmp[0];
 265             p_tmp[0] = p_tmp[1];
 266             p_tmp[1] = tmp;
 267             p_tmp += 2;
 268         }
 269 #endif
 270     }
 271
 272     if( p_sys->b_start )
 273         p_block_in->i_pts = p_block_in->i_dts = 1;
 274     else
 275         p_block_in->i_pts = p_block_in->i_dts = 0;
 276
 277     while( (p_block_out = p_sys->p_packetizer->pf_packetize(
 278                 p_sys->p_packetizer, &p_block_in )) )
 279     {
 280         p_sys->b_start = VLC_FALSE;
 281
 282         while( p_block_out )
 283         {
 284             block_t *p_next = p_block_out->p_next;
 285
 286             /* We assume a constant bitrate */
 287             if( p_block_out->i_length )
 288             p_sys->i_mux_rate =
 289                 p_block_out->i_buffer * I64C(1000000) / p_block_out->i_length;
 290             p_input->stream.i_mux_rate = p_sys->i_mux_rate / 50;
 291
 292             input_ClockManageRef( p_input,
 293                                   p_input->stream.p_selected_program,
 294                                   p_block_out->i_pts * 9 / 100 );
 295
 296             p_block_in->b_discontinuity = 0;
 297             p_block_out->i_dts = p_block_out->i_pts =
 298                 input_ClockGetTS( p_input, p_input->stream.p_selected_program,
 299                                   p_block_out->i_pts * 9 / 100 );
 300
 301             es_out_Send( p_input->p_es_out, p_sys->p_es, p_block_out );
 302
 303             p_block_out = p_next;
 304         }
 305     }
 306
 307     return 1;
 308 }
 309
 310 /*****************************************************************************
 311  * Control:
 312  *****************************************************************************/
 313 static int Control( input_thread_t *p_input, int i_query, va_list args )
 314 {
 315     demux_sys_t *p_sys  = (demux_sys_t *)p_input->p_demux_data;
 316     int64_t *pi64;
 317
 318     switch( i_query )
 319     {
 320         case DEMUX_GET_TIME:
 321             pi64 = (int64_t*)va_arg( args, int64_t * );
 322             if( p_sys->i_mux_rate > 0 )
 323             {
 324                 *pi64 = I64C(1000000) * stream_Tell( p_input->s ) /
 325                         p_sys->i_mux_rate;
 326                 return VLC_SUCCESS;
 327             }
 328             *pi64 = 0;
 329             return VLC_EGENERIC;
 330
 331         case DEMUX_GET_LENGTH:
 332             pi64 = (int64_t*)va_arg( args, int64_t * );
 333             if( p_sys->i_mux_rate > 0 )
 334             {
 335                 *pi64 = I64C(1000000) * stream_Size( p_input->s ) /
 336                         p_sys->i_mux_rate;
 337                 return VLC_SUCCESS;
 338             }
 339             *pi64 = 0;
 340             return VLC_EGENERIC;
 341
 342         default:
 343             return demux_vaControlDefault( p_input, i_query, args );
 344     }
 345 }