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 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <vlc_common.h>
  34 #include <vlc_plugin.h>
  35 #include <vlc_demux.h>
  36 #include <vlc_codec.h>
  37 #include <vlc_input.h>
  38
  39 #define MPGA_PACKET_SIZE 1024
  40
  41 /*****************************************************************************
  42  * Module descriptor
  43  *****************************************************************************/
  44 static int  Open ( vlc_object_t * );
  45 static void Close( vlc_object_t * );
  46
  47 vlc_module_begin();
  48     set_category( CAT_INPUT );
  49     set_subcategory( SUBCAT_INPUT_DEMUX );
  50     set_description( N_("MPEG audio / MP3 demuxer" ) );
  51     set_capability( "demux", 100 );
  52     set_callbacks( Open, Close );
  53     add_shortcut( "mpga" );
  54     add_shortcut( "mp3" );
  55 vlc_module_end();
  56
  57 /*****************************************************************************
  58  * Local prototypes
  59  *****************************************************************************/
  60 static int Demux  ( demux_t * );
  61 static int Control( demux_t *, int, va_list );
  62
  63 struct demux_sys_t
  64 {
  65     es_out_id_t *p_es;
  66
  67     bool  b_start;
  68     decoder_t   *p_packetizer;
  69
  70     mtime_t     i_pts;
  71     mtime_t     i_time_offset;
  72     int         i_bitrate_avg;  /* extracted from Xing header */
  73
  74     bool b_initial_sync_failed;
  75
  76     int i_xing_frames;
  77     int i_xing_bytes;
  78     int i_xing_bitrate_avg;
  79     int i_xing_frame_samples;
  80     block_t *p_block_in, *p_block_out;
  81 };
  82
  83 static int HeaderCheck( uint32_t h )
  84 {
  85     if( ((( h >> 21 )&0x07FF) != 0x07FF )   /* header sync */
  86         || (((h >> 17)&0x03) == 0 )         /* valid layer ?*/
  87         || (((h >> 12)&0x0F) == 0x0F )
  88         || (((h >> 12)&0x0F) == 0x00 )      /* valid bitrate ? */
  89         || (((h >> 10) & 0x03) == 0x03 )    /* valide sampling freq ? */
  90         || ((h & 0x03) == 0x02 ))           /* valid emphasis ? */
  91     {
  92         return false;
  93     }
  94     return true;
  95 }
  96
  97 #define MPGA_VERSION( h )   ( 1 - (((h)>>19)&0x01) )
  98 #define MPGA_LAYER( h )     ( 3 - (((h)>>17)&0x03) )
  99 #define MPGA_MODE(h)        (((h)>> 6)&0x03)
 100
 101 static int mpga_frame_samples( uint32_t h )
 102 {
 103     switch( MPGA_LAYER(h) )
 104     {
 105         case 0:
 106             return 384;
 107         case 1:
 108             return 1152;
 109         case 2:
 110             return MPGA_VERSION(h) ? 576 : 1152;
 111         default:
 112             return 0;
 113     }
 114 }
 115
 116
 117 /*****************************************************************************
 118  * Open: initializes demux structures
 119  *****************************************************************************/
 120 static int Open( vlc_object_t * p_this )
 121 {
 122     demux_t     *p_demux = (demux_t*)p_this;
 123     demux_sys_t *p_sys;
 124     bool   b_forced = false;
 125
 126     uint32_t     header;
 127     const uint8_t     *p_peek;
 128     block_t     *p_block_in, *p_block_out;
 129
 130     if( demux_IsPathExtension( p_demux, ".mp3" ) )
 131         b_forced = true;
 132
 133     if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
 134
 135     if( !HeaderCheck( header = GetDWBE( p_peek ) ) )
 136     {
 137         bool b_ok = false;
 138         int i_peek;
 139
 140         if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;
 141
 142         i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );
 143         while( i_peek > 4 )
 144         {
 145             if( HeaderCheck( header = GetDWBE( p_peek ) ) )
 146             {
 147                 b_ok = true;
 148                 break;
 149             }
 150             p_peek += 1;
 151             i_peek -= 1;
 152         }
 153         if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;
 154     }
 155
 156     DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
 157     memset( p_sys, 0, sizeof( demux_sys_t ) );
 158     p_sys->p_es = 0;
 159     p_sys->b_start = true;
 160
 161     /* Load the mpeg audio packetizer */
 162     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 163     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 164     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 165
 166     /* Xing header */
 167     if( HeaderCheck( header ) )
 168     {
 169         int i_xing, i_skip;
 170         const uint8_t *p_xing;
 171
 172         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 173             return VLC_SUCCESS; /* No header */
 174
 175         if( MPGA_VERSION( header ) == 0 )
 176         {
 177             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 178         }
 179         else
 180         {
 181             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 182         }
 183
 184         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 185         {
 186             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 187
 188             p_xing += i_skip + 8;
 189             i_xing -= i_skip + 8;
 190
 191             i_skip = 0;
 192             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 193             {
 194                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 195                 i_skip += 4;
 196             }
 197             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 198             {
 199                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 200                 i_skip += 4;
 201             }
 202             if( i_flags&0x04 )   /* XING_TOC */
 203             {
 204                 i_skip += 100;
 205             }
 206
 207             // FIXME: doesn't return the right bitrage average, at least
 208             // with some MP3's
 209             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 210             {
 211                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 212                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 213                          p_sys->i_xing_bitrate_avg );
 214             }
 215
 216             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 217             {
 218                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 219                 msg_Dbg( p_demux, "xing frames&bytes value present "
 220                          "(%d bytes, %d frames, %d samples/frame)",
 221                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 222                          p_sys->i_xing_frame_samples );
 223             }
 224         }
 225     }
 226
 227     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 228     {
 229         return VLC_EGENERIC;
 230     }
 231     p_block_in->i_pts = p_block_in->i_dts = 1;
 232     p_block_out = p_sys->p_packetizer->pf_packetize(
 233         p_sys->p_packetizer, &p_block_in );
 234
 235     if( p_block_out == NULL )
 236     {
 237         msg_Dbg( p_demux, "did not sync on first block" );
 238         p_sys->b_initial_sync_failed = true;
 239     }
 240     else
 241         p_sys->b_initial_sync_failed = false;
 242
 243     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 244
 245     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 246         p_sys->i_xing_frame_samples )
 247     {
 248         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * INT64_C(8) *
 249             p_sys->p_packetizer->fmt_out.audio.i_rate /
 250             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 251     }
 252
 253     p_sys->p_block_in = p_block_in;
 254     p_sys->p_block_out = p_block_out;
 255
 256     /* */
 257     p_sys->p_packetizer->fmt_out.b_packetized = true;
 258     p_sys->p_es = es_out_Add( p_demux->out,
 259                               &p_sys->p_packetizer->fmt_out);
 260     return VLC_SUCCESS;
 261 }
 262
 263 /*****************************************************************************
 264  * Demux: reads and demuxes data packets
 265  *****************************************************************************
 266  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 267  *****************************************************************************/
 268 static int Demux( demux_t *p_demux )
 269 {
 270     demux_sys_t *p_sys = p_demux->p_sys;
 271     block_t *p_block_in, *p_block_out;
 272     if( p_sys->b_start )
 273     {
 274         p_sys->b_start = false;
 275         p_block_in = p_sys->p_block_in;
 276         p_sys->p_block_in = NULL;
 277         p_block_out = p_sys->p_block_out;
 278         p_sys->p_block_out = NULL;
 279     }
 280     else
 281     {
 282         if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) )
 283             == NULL )
 284         {
 285             return 0;
 286         }
 287         if( p_demux->p_sys->b_initial_sync_failed == true )
 288         {
 289             p_block_in->i_pts = p_block_in->i_dts = 1;
 290             /* Only try to resync once */
 291             p_demux->p_sys->b_initial_sync_failed = 0;
 292         }
 293         else
 294             p_block_in->i_pts = p_block_in->i_dts = 0;
 295         p_block_out = p_sys->p_packetizer->pf_packetize(
 296             p_sys->p_packetizer, &p_block_in );
 297     }
 298
 299
 300     while( p_block_out )
 301     {
 302         while( p_block_out )
 303         {
 304             block_t *p_next = p_block_out->p_next;
 305
 306             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 307
 308             p_block_out->p_next = NULL;
 309             p_sys->i_pts = p_block_out->i_pts;
 310             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 311
 312             p_block_out = p_next;
 313         }
 314         p_block_out = p_sys->p_packetizer->pf_packetize(
 315             p_sys->p_packetizer, &p_block_in );
 316     }
 317     return 1;
 318 }
 319
 320 /*****************************************************************************
 321  * Close: frees unused data
 322  *****************************************************************************/
 323 static void Close( vlc_object_t * p_this )
 324 {
 325     demux_t     *p_demux = (demux_t*)p_this;
 326     demux_sys_t *p_sys = p_demux->p_sys;
 327
 328     DESTROY_PACKETIZER( p_sys->p_packetizer );
 329     if( p_sys->p_block_out ) block_Release( p_sys->p_block_out );
 330
 331     free( p_sys );
 332 }
 333
 334 /*****************************************************************************
 335  * Control:
 336  *****************************************************************************/
 337 static int Control( demux_t *p_demux, int i_query, va_list args )
 338 {
 339     demux_sys_t *p_sys  = p_demux->p_sys;
 340     int64_t *pi64;
 341     bool *pb_bool;
 342     int i_ret;
 343     va_list args_save;
 344
 345     va_copy ( args_save, args );
 346
 347     switch( i_query )
 348     {
 349         case DEMUX_HAS_UNSUPPORTED_META:
 350             pb_bool = (bool*)va_arg( args, bool* );
 351             *pb_bool = true;
 352             return VLC_SUCCESS;
 353
 354         case DEMUX_GET_TIME:
 355             pi64 = (int64_t*)va_arg( args, int64_t * );
 356             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 357             return VLC_SUCCESS;
 358
 359         case DEMUX_GET_LENGTH:
 360             i_ret = demux_vaControlHelper( p_demux->s, 0, -1,
 361                                             p_sys->i_bitrate_avg, 1, i_query,
 362                                             args );
 363             /* No bitrate, we can't have it precisely, but we can compute
 364              * a raw approximation with time/position */
 365             if( i_ret && !p_sys->i_bitrate_avg )
 366             {
 367                 float f_pos = (double)(uint64_t)( stream_Tell( p_demux->s ) ) /
 368                               (double)(uint64_t)( stream_Size( p_demux->s ) );
 369                 /* The first few seconds are guaranteed to be very whacky,
 370                  * don't bother trying ... Too bad */
 371                 if( f_pos < 0.01 ||
 372                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 373                     return VLC_EGENERIC;
 374
 375                 pi64 = (int64_t *)va_arg( args_save, int64_t * );
 376                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 377                 return VLC_SUCCESS;
 378             }
 379             va_end( args_save );
 380             return i_ret;
 381
 382         case DEMUX_SET_TIME:
 383             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 384              * needed for multi-input */
 385         default:
 386             i_ret = demux_vaControlHelper( p_demux->s, 0, -1,
 387                                             p_sys->i_bitrate_avg, 1, i_query,
 388                                             args );
 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 = INT64_C(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 }