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

   1 /*****************************************************************************
   2  * mpga.c : MPEG-I/II Audio input module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2001-2004 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Gildas Bazin <gbazin@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 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 General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #include <vlc/vlc.h>
  30 #include <vlc_demux.h>
  31 #include <vlc_codec.h>
  32 #include <vlc_input.h>
  33
  34 #define MPGA_PACKET_SIZE 1024
  35
  36 /*****************************************************************************
  37  * Module descriptor
  38  *****************************************************************************/
  39 static int  Open ( vlc_object_t * );
  40 static void Close( vlc_object_t * );
  41
  42 vlc_module_begin();
  43     set_category( CAT_INPUT );
  44     set_subcategory( SUBCAT_INPUT_DEMUX );
  45     set_description( _("MPEG audio / MP3 demuxer" ) );
  46     set_capability( "demux2", 100 );
  47     set_callbacks( Open, Close );
  48     add_shortcut( "mpga" );
  49     add_shortcut( "mp3" );
  50 vlc_module_end();
  51
  52 /*****************************************************************************
  53  * Local prototypes
  54  *****************************************************************************/
  55 static int Demux  ( demux_t * );
  56 static int Control( demux_t *, int, va_list );
  57
  58 struct demux_sys_t
  59 {
  60     es_out_id_t *p_es;
  61     vlc_meta_t  *meta;
  62
  63     vlc_bool_t  b_start;
  64     decoder_t   *p_packetizer;
  65
  66     mtime_t     i_pts;
  67     mtime_t     i_time_offset;
  68     int         i_bitrate_avg;  /* extracted from Xing header */
  69
  70     vlc_bool_t b_initial_sync_failed;
  71
  72     int i_xing_frames;
  73     int i_xing_bytes;
  74     int i_xing_bitrate_avg;
  75     int i_xing_frame_samples;
  76     block_t *p_block_in, *p_block_out;
  77 };
  78
  79 static int HeaderCheck( uint32_t h )
  80 {
  81     if( ((( h >> 21 )&0x07FF) != 0x07FF )   /* header sync */
  82         || (((h >> 17)&0x03) == 0 )         /* valid layer ?*/
  83         || (((h >> 12)&0x0F) == 0x0F )
  84         || (((h >> 12)&0x0F) == 0x00 )      /* valid bitrate ? */
  85         || (((h >> 10) & 0x03) == 0x03 )    /* valide sampling freq ? */
  86         || ((h & 0x03) == 0x02 ))           /* valid emphasis ? */
  87     {
  88         return VLC_FALSE;
  89     }
  90     return VLC_TRUE;
  91 }
  92
  93 #define MPGA_VERSION( h )   ( 1 - (((h)>>19)&0x01) )
  94 #define MPGA_LAYER( h )     ( 3 - (((h)>>17)&0x03) )
  95 #define MPGA_MODE(h)        (((h)>> 6)&0x03)
  96
  97 static int mpga_frame_samples( uint32_t h )
  98 {
  99     switch( MPGA_LAYER(h) )
 100     {
 101         case 0:
 102             return 384;
 103         case 1:
 104             return 1152;
 105         case 2:
 106             return MPGA_VERSION(h) ? 576 : 1152;
 107         default:
 108             return 0;
 109     }
 110 }
 111
 112
 113 /*****************************************************************************
 114  * Open: initializes demux structures
 115  *****************************************************************************/
 116 static int Open( vlc_object_t * p_this )
 117 {
 118     demux_t     *p_demux = (demux_t*)p_this;
 119     demux_sys_t *p_sys;
 120     vlc_bool_t   b_forced = VLC_FALSE;
 121
 122     uint32_t     header;
 123     uint8_t     *p_peek;
 124     module_t    *p_id3;
 125     block_t     *p_block_in, *p_block_out;
 126
 127     if( p_demux->psz_path )
 128     {
 129         int  i_len = strlen( p_demux->psz_path );
 130         if( i_len > 4 && !strcasecmp( &p_demux->psz_path[i_len - 4], ".mp3" ) )
 131         {
 132             b_forced = VLC_TRUE;
 133         }
 134     }
 135
 136     if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
 137
 138     if( !HeaderCheck( header = GetDWBE( p_peek ) ) )
 139     {
 140         vlc_bool_t b_ok = VLC_FALSE;
 141         int i_peek;
 142
 143         if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;
 144
 145         i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );
 146         while( i_peek > 4 )
 147         {
 148             if( HeaderCheck( header = GetDWBE( p_peek ) ) )
 149             {
 150                 b_ok = VLC_TRUE;
 151                 break;
 152             }
 153             p_peek += 1;
 154             i_peek -= 1;
 155         }
 156         if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;
 157     }
 158
 159     STANDARD_DEMUX_INIT; p_sys = p_demux->p_sys;
 160     memset( p_sys, 0, sizeof( demux_sys_t ) );
 161     p_sys->p_es = 0;
 162     p_sys->b_start = VLC_TRUE;
 163     p_sys->meta = 0;
 164
 165     /* Load the mpeg audio packetizer */
 166     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 167     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 168     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 169
 170     /* Xing header */
 171     if( HeaderCheck( header ) )
 172     {
 173         int i_xing, i_skip;
 174         uint8_t *p_xing;
 175
 176         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 177             return VLC_SUCCESS; /* No header */
 178
 179         if( MPGA_VERSION( header ) == 0 )
 180         {
 181             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 182         }
 183         else
 184         {
 185             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 186         }
 187
 188         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 189         {
 190             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 191
 192             p_xing += i_skip + 8;
 193             i_xing -= i_skip + 8;
 194
 195             i_skip = 0;
 196             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 197             {
 198                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 199                 i_skip += 4;
 200             }
 201             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 202             {
 203                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 204                 i_skip += 4;
 205             }
 206             if( i_flags&0x04 )   /* XING_TOC */
 207             {
 208                 i_skip += 100;
 209             }
 210
 211             // FIXME: doesn't return the right bitrage average, at least
 212             // with some MP3's
 213             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 214             {
 215                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 216                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 217                          p_sys->i_xing_bitrate_avg );
 218             }
 219
 220             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 221             {
 222                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 223                 msg_Dbg( p_demux, "xing frames&bytes value present "
 224                          "(%d bytes, %d frames, %d samples/frame)",
 225                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 226                          p_sys->i_xing_frame_samples );
 227             }
 228         }
 229     }
 230
 231     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 232     {
 233         return VLC_EGENERIC;
 234     }
 235     p_block_in->i_pts = p_block_in->i_dts = 1;
 236     p_block_out = p_sys->p_packetizer->pf_packetize(
 237         p_sys->p_packetizer, &p_block_in );
 238
 239     if( p_block_out == NULL )
 240     {
 241         msg_Dbg( p_demux, "did not sync on first block" );
 242         p_sys->b_initial_sync_failed = VLC_TRUE;
 243     }
 244     else
 245         p_sys->b_initial_sync_failed = VLC_FALSE;
 246
 247     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 248
 249     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 250         p_sys->i_xing_frame_samples )
 251     {
 252         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * I64C(8) *
 253             p_sys->p_packetizer->fmt_out.audio.i_rate /
 254             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 255     }
 256
 257     p_sys->p_block_in = p_block_in;
 258     p_sys->p_block_out = p_block_out;
 259
 260     /* Parse possible id3 header */
 261     if( ( p_id3 = module_Need( p_demux, "meta reader", NULL, 0 ) ) )
 262     {
 263         p_sys->meta = (vlc_meta_t *)p_demux->p_private;
 264         p_demux->p_private = NULL;
 265         module_Unneed( p_demux, p_id3 );
 266     }
 267
 268     /* */
 269     p_sys->p_packetizer->fmt_out.b_packetized = VLC_TRUE;
 270     vlc_audio_replay_gain_MergeFromMeta( &p_sys->p_packetizer->fmt_out.audio_replay_gain,
 271                                          p_sys->meta );
 272     p_sys->p_es = es_out_Add( p_demux->out,
 273                               &p_sys->p_packetizer->fmt_out);
 274     return VLC_SUCCESS;
 275 }
 276
 277 /*****************************************************************************
 278  * Demux: reads and demuxes data packets
 279  *****************************************************************************
 280  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 281  *****************************************************************************/
 282 static int Demux( demux_t *p_demux )
 283 {
 284     demux_sys_t *p_sys = p_demux->p_sys;
 285     block_t *p_block_in, *p_block_out;
 286     if( p_sys->b_start )
 287     {
 288         p_sys->b_start = VLC_FALSE;
 289         p_block_in = p_sys->p_block_in;
 290         p_sys->p_block_in = NULL;
 291         p_block_out = p_sys->p_block_out;
 292         p_sys->p_block_out = NULL;
 293     }
 294     else
 295     {
 296         if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) )
 297             == NULL )
 298         {
 299             return 0;
 300         }
 301         if( p_demux->p_sys->b_initial_sync_failed == VLC_TRUE )
 302         {
 303             p_block_in->i_pts = p_block_in->i_dts = 1;
 304             /* Only try to resync once */
 305             p_demux->p_sys->b_initial_sync_failed = 0;
 306         }
 307         else
 308             p_block_in->i_pts = p_block_in->i_dts = 0;
 309         p_block_out = p_sys->p_packetizer->pf_packetize(
 310             p_sys->p_packetizer, &p_block_in );
 311     }
 312
 313
 314     while( p_block_out )
 315     {
 316         while( p_block_out )
 317         {
 318             block_t *p_next = p_block_out->p_next;
 319
 320             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 321
 322             p_block_out->p_next = NULL;
 323             p_sys->i_pts = p_block_out->i_pts;
 324             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 325
 326             p_block_out = p_next;
 327         }
 328         p_block_out = p_sys->p_packetizer->pf_packetize(
 329             p_sys->p_packetizer, &p_block_in );
 330     }
 331     return 1;
 332 }
 333
 334 /*****************************************************************************
 335  * Close: frees unused data
 336  *****************************************************************************/
 337 static void Close( vlc_object_t * p_this )
 338 {
 339     demux_t     *p_demux = (demux_t*)p_this;
 340     demux_sys_t *p_sys = p_demux->p_sys;
 341
 342     DESTROY_PACKETIZER( p_sys->p_packetizer );
 343     if( p_sys->meta ) vlc_meta_Delete( p_sys->meta );
 344     if( p_sys->p_block_out ) block_Release( p_sys->p_block_out );
 345
 346     free( p_sys );
 347 }
 348
 349 /*****************************************************************************
 350  * Control:
 351  *****************************************************************************/
 352 static int Control( demux_t *p_demux, int i_query, va_list args )
 353 {
 354     demux_sys_t *p_sys  = p_demux->p_sys;
 355     int64_t *pi64;
 356     vlc_meta_t *p_meta;
 357     int i_ret;
 358
 359     switch( i_query )
 360     {
 361         case DEMUX_GET_META:
 362             p_meta = (vlc_meta_t *)va_arg( args, vlc_meta_t* );
 363             vlc_meta_Merge( p_meta, p_sys->meta );
 364             return VLC_SUCCESS;
 365
 366         case DEMUX_GET_TIME:
 367             pi64 = (int64_t*)va_arg( args, int64_t * );
 368             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 369             return VLC_SUCCESS;
 370
 371         case DEMUX_SET_TIME:
 372             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 373              * needed for multi-input */
 374
 375         default:
 376             i_ret = demux2_vaControlHelper( p_demux->s, 0, -1,
 377                                             p_sys->i_bitrate_avg, 1, i_query,
 378                                             args );
 379             /* No bitrate, we can't have it precisely, but we can compute
 380              * a raw approximation with time/position */
 381             if( i_ret && i_query == DEMUX_GET_LENGTH &&!p_sys->i_bitrate_avg )
 382             {
 383                 float f_pos = (double)( stream_Tell( p_demux->s ) ) /
 384                               (double)( stream_Size( p_demux->s ) );
 385                 /* The first few seconds are guaranteed to be very whacky,
 386                  * don't bother trying ... Too bad */
 387                 if( f_pos < 0.01 ||
 388                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 389                     return VLC_EGENERIC;
 390
 391                 pi64 = (int64_t *)va_arg( args, int64_t * );
 392                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 393                 return VLC_SUCCESS;
 394             }
 395             if( !i_ret && p_sys->i_bitrate_avg > 0 &&
 396                 (i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME) )
 397             {
 398                 int64_t i_time = I64C(8000000) * stream_Tell(p_demux->s) /
 399                     p_sys->i_bitrate_avg;
 400
 401                 /* Fix time_offset */
 402                 if( i_time >= 0 ) p_sys->i_time_offset = i_time - p_sys->i_pts;
 403             }
 404             return i_ret;
 405     }
 406 }