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     const uint8_t     *p_peek;
 124     module_t    *p_id3;
 125     block_t     *p_block_in, *p_block_out;
 126
 127     if( demux2_IsPathExtension( p_demux, ".mp3" ) )
 128         b_forced = VLC_TRUE;
 129
 130     if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
 131
 132     if( !HeaderCheck( header = GetDWBE( p_peek ) ) )
 133     {
 134         vlc_bool_t b_ok = VLC_FALSE;
 135         int i_peek;
 136
 137         if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;
 138
 139         i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );
 140         while( i_peek > 4 )
 141         {
 142             if( HeaderCheck( header = GetDWBE( p_peek ) ) )
 143             {
 144                 b_ok = VLC_TRUE;
 145                 break;
 146             }
 147             p_peek += 1;
 148             i_peek -= 1;
 149         }
 150         if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;
 151     }
 152
 153     DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
 154     memset( p_sys, 0, sizeof( demux_sys_t ) );
 155     p_sys->p_es = 0;
 156     p_sys->b_start = VLC_TRUE;
 157     p_sys->meta = 0;
 158
 159     /* Load the mpeg audio packetizer */
 160     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 161     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 162     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 163
 164     /* Xing header */
 165     if( HeaderCheck( header ) )
 166     {
 167         int i_xing, i_skip;
 168         const uint8_t *p_xing;
 169
 170         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 171             return VLC_SUCCESS; /* No header */
 172
 173         if( MPGA_VERSION( header ) == 0 )
 174         {
 175             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 176         }
 177         else
 178         {
 179             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 180         }
 181
 182         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 183         {
 184             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 185
 186             p_xing += i_skip + 8;
 187             i_xing -= i_skip + 8;
 188
 189             i_skip = 0;
 190             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 191             {
 192                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 193                 i_skip += 4;
 194             }
 195             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 196             {
 197                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 198                 i_skip += 4;
 199             }
 200             if( i_flags&0x04 )   /* XING_TOC */
 201             {
 202                 i_skip += 100;
 203             }
 204
 205             // FIXME: doesn't return the right bitrage average, at least
 206             // with some MP3's
 207             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 208             {
 209                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 210                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 211                          p_sys->i_xing_bitrate_avg );
 212             }
 213
 214             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 215             {
 216                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 217                 msg_Dbg( p_demux, "xing frames&bytes value present "
 218                          "(%d bytes, %d frames, %d samples/frame)",
 219                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 220                          p_sys->i_xing_frame_samples );
 221             }
 222         }
 223     }
 224
 225     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 226     {
 227         return VLC_EGENERIC;
 228     }
 229     p_block_in->i_pts = p_block_in->i_dts = 1;
 230     p_block_out = p_sys->p_packetizer->pf_packetize(
 231         p_sys->p_packetizer, &p_block_in );
 232
 233     if( p_block_out == NULL )
 234     {
 235         msg_Dbg( p_demux, "did not sync on first block" );
 236         p_sys->b_initial_sync_failed = VLC_TRUE;
 237     }
 238     else
 239         p_sys->b_initial_sync_failed = VLC_FALSE;
 240
 241     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 242
 243     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 244         p_sys->i_xing_frame_samples )
 245     {
 246         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * I64C(8) *
 247             p_sys->p_packetizer->fmt_out.audio.i_rate /
 248             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 249     }
 250
 251     p_sys->p_block_in = p_block_in;
 252     p_sys->p_block_out = p_block_out;
 253
 254     /* Parse possible id3 header */
 255     if( ( p_id3 = module_Need( p_demux, "meta reader", NULL, 0 ) ) )
 256     {
 257         p_sys->meta = (vlc_meta_t *)p_demux->p_private;
 258         p_demux->p_private = NULL;
 259         module_Unneed( p_demux, p_id3 );
 260     }
 261
 262     /* */
 263     p_sys->p_packetizer->fmt_out.b_packetized = VLC_TRUE;
 264     vlc_audio_replay_gain_MergeFromMeta( &p_sys->p_packetizer->fmt_out.audio_replay_gain,
 265                                          p_sys->meta );
 266     p_sys->p_es = es_out_Add( p_demux->out,
 267                               &p_sys->p_packetizer->fmt_out);
 268     return VLC_SUCCESS;
 269 }
 270
 271 /*****************************************************************************
 272  * Demux: reads and demuxes data packets
 273  *****************************************************************************
 274  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 275  *****************************************************************************/
 276 static int Demux( demux_t *p_demux )
 277 {
 278     demux_sys_t *p_sys = p_demux->p_sys;
 279     block_t *p_block_in, *p_block_out;
 280     if( p_sys->b_start )
 281     {
 282         p_sys->b_start = VLC_FALSE;
 283         p_block_in = p_sys->p_block_in;
 284         p_sys->p_block_in = NULL;
 285         p_block_out = p_sys->p_block_out;
 286         p_sys->p_block_out = NULL;
 287     }
 288     else
 289     {
 290         if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) )
 291             == NULL )
 292         {
 293             return 0;
 294         }
 295         if( p_demux->p_sys->b_initial_sync_failed == VLC_TRUE )
 296         {
 297             p_block_in->i_pts = p_block_in->i_dts = 1;
 298             /* Only try to resync once */
 299             p_demux->p_sys->b_initial_sync_failed = 0;
 300         }
 301         else
 302             p_block_in->i_pts = p_block_in->i_dts = 0;
 303         p_block_out = p_sys->p_packetizer->pf_packetize(
 304             p_sys->p_packetizer, &p_block_in );
 305     }
 306
 307
 308     while( p_block_out )
 309     {
 310         while( p_block_out )
 311         {
 312             block_t *p_next = p_block_out->p_next;
 313
 314             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 315
 316             p_block_out->p_next = NULL;
 317             p_sys->i_pts = p_block_out->i_pts;
 318             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 319
 320             p_block_out = p_next;
 321         }
 322         p_block_out = p_sys->p_packetizer->pf_packetize(
 323             p_sys->p_packetizer, &p_block_in );
 324     }
 325     return 1;
 326 }
 327
 328 /*****************************************************************************
 329  * Close: frees unused data
 330  *****************************************************************************/
 331 static void Close( vlc_object_t * p_this )
 332 {
 333     demux_t     *p_demux = (demux_t*)p_this;
 334     demux_sys_t *p_sys = p_demux->p_sys;
 335
 336     DESTROY_PACKETIZER( p_sys->p_packetizer );
 337     if( p_sys->meta ) vlc_meta_Delete( p_sys->meta );
 338     if( p_sys->p_block_out ) block_Release( p_sys->p_block_out );
 339
 340     free( p_sys );
 341 }
 342
 343 /*****************************************************************************
 344  * Control:
 345  *****************************************************************************/
 346 static int Control( demux_t *p_demux, int i_query, va_list args )
 347 {
 348     demux_sys_t *p_sys  = p_demux->p_sys;
 349     int64_t *pi64;
 350     vlc_meta_t *p_meta;
 351     int i_ret;
 352
 353     switch( i_query )
 354     {
 355         case DEMUX_GET_META:
 356             p_meta = (vlc_meta_t *)va_arg( args, vlc_meta_t* );
 357             vlc_meta_Merge( p_meta, p_sys->meta );
 358             return VLC_SUCCESS;
 359
 360         case DEMUX_GET_TIME:
 361             pi64 = (int64_t*)va_arg( args, int64_t * );
 362             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 363             return VLC_SUCCESS;
 364
 365         case DEMUX_SET_TIME:
 366             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 367              * needed for multi-input */
 368
 369         default:
 370             i_ret = demux2_vaControlHelper( p_demux->s, 0, -1,
 371                                             p_sys->i_bitrate_avg, 1, i_query,
 372                                             args );
 373             /* No bitrate, we can't have it precisely, but we can compute
 374              * a raw approximation with time/position */
 375             if( i_ret && i_query == DEMUX_GET_LENGTH &&!p_sys->i_bitrate_avg )
 376             {
 377                 float f_pos = (double)( stream_Tell( p_demux->s ) ) /
 378                               (double)( stream_Size( p_demux->s ) );
 379                 /* The first few seconds are guaranteed to be very whacky,
 380                  * don't bother trying ... Too bad */
 381                 if( f_pos < 0.01 ||
 382                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 383                     return VLC_EGENERIC;
 384
 385                 pi64 = (int64_t *)va_arg( args, int64_t * );
 386                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 387                 return VLC_SUCCESS;
 388             }
 389             if( !i_ret && p_sys->i_bitrate_avg > 0 &&
 390                 (i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME) )
 391             {
 392                 int64_t i_time = I64C(8000000) * stream_Tell(p_demux->s) /
 393                     p_sys->i_bitrate_avg;
 394
 395                 /* Fix time_offset */
 396                 if( i_time >= 0 ) p_sys->i_time_offset = i_time - p_sys->i_pts;
 397             }
 398             return i_ret;
 399     }
 400 }