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
  62     vlc_bool_t  b_start;
  63     decoder_t   *p_packetizer;
  64
  65     mtime_t     i_pts;
  66     mtime_t     i_time_offset;
  67     int         i_bitrate_avg;  /* extracted from Xing header */
  68
  69     vlc_bool_t b_initial_sync_failed;
  70
  71     int i_xing_frames;
  72     int i_xing_bytes;
  73     int i_xing_bitrate_avg;
  74     int i_xing_frame_samples;
  75     block_t *p_block_in, *p_block_out;
  76 };
  77
  78 static int HeaderCheck( uint32_t h )
  79 {
  80     if( ((( h >> 21 )&0x07FF) != 0x07FF )   /* header sync */
  81         || (((h >> 17)&0x03) == 0 )         /* valid layer ?*/
  82         || (((h >> 12)&0x0F) == 0x0F )
  83         || (((h >> 12)&0x0F) == 0x00 )      /* valid bitrate ? */
  84         || (((h >> 10) & 0x03) == 0x03 )    /* valide sampling freq ? */
  85         || ((h & 0x03) == 0x02 ))           /* valid emphasis ? */
  86     {
  87         return VLC_FALSE;
  88     }
  89     return VLC_TRUE;
  90 }
  91
  92 #define MPGA_VERSION( h )   ( 1 - (((h)>>19)&0x01) )
  93 #define MPGA_LAYER( h )     ( 3 - (((h)>>17)&0x03) )
  94 #define MPGA_MODE(h)        (((h)>> 6)&0x03)
  95
  96 static int mpga_frame_samples( uint32_t h )
  97 {
  98     switch( MPGA_LAYER(h) )
  99     {
 100         case 0:
 101             return 384;
 102         case 1:
 103             return 1152;
 104         case 2:
 105             return MPGA_VERSION(h) ? 576 : 1152;
 106         default:
 107             return 0;
 108     }
 109 }
 110
 111
 112 /*****************************************************************************
 113  * Open: initializes demux structures
 114  *****************************************************************************/
 115 static int Open( vlc_object_t * p_this )
 116 {
 117     demux_t     *p_demux = (demux_t*)p_this;
 118     demux_sys_t *p_sys;
 119     vlc_bool_t   b_forced = VLC_FALSE;
 120
 121     uint32_t     header;
 122     const uint8_t     *p_peek;
 123     block_t     *p_block_in, *p_block_out;
 124
 125     if( demux2_IsPathExtension( p_demux, ".mp3" ) )
 126         b_forced = VLC_TRUE;
 127
 128     if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
 129
 130     if( !HeaderCheck( header = GetDWBE( p_peek ) ) )
 131     {
 132         vlc_bool_t b_ok = VLC_FALSE;
 133         int i_peek;
 134
 135         if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;
 136
 137         i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );
 138         while( i_peek > 4 )
 139         {
 140             if( HeaderCheck( header = GetDWBE( p_peek ) ) )
 141             {
 142                 b_ok = VLC_TRUE;
 143                 break;
 144             }
 145             p_peek += 1;
 146             i_peek -= 1;
 147         }
 148         if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;
 149     }
 150
 151     DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
 152     memset( p_sys, 0, sizeof( demux_sys_t ) );
 153     p_sys->p_es = 0;
 154     p_sys->b_start = VLC_TRUE;
 155
 156     /* Load the mpeg audio packetizer */
 157     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 158     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 159     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 160
 161     /* Xing header */
 162     if( HeaderCheck( header ) )
 163     {
 164         int i_xing, i_skip;
 165         const uint8_t *p_xing;
 166
 167         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 168             return VLC_SUCCESS; /* No header */
 169
 170         if( MPGA_VERSION( header ) == 0 )
 171         {
 172             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 173         }
 174         else
 175         {
 176             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 177         }
 178
 179         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 180         {
 181             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 182
 183             p_xing += i_skip + 8;
 184             i_xing -= i_skip + 8;
 185
 186             i_skip = 0;
 187             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 188             {
 189                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 190                 i_skip += 4;
 191             }
 192             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 193             {
 194                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 195                 i_skip += 4;
 196             }
 197             if( i_flags&0x04 )   /* XING_TOC */
 198             {
 199                 i_skip += 100;
 200             }
 201
 202             // FIXME: doesn't return the right bitrage average, at least
 203             // with some MP3's
 204             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 205             {
 206                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 207                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 208                          p_sys->i_xing_bitrate_avg );
 209             }
 210
 211             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 212             {
 213                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 214                 msg_Dbg( p_demux, "xing frames&bytes value present "
 215                          "(%d bytes, %d frames, %d samples/frame)",
 216                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 217                          p_sys->i_xing_frame_samples );
 218             }
 219         }
 220     }
 221
 222     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 223     {
 224         return VLC_EGENERIC;
 225     }
 226     p_block_in->i_pts = p_block_in->i_dts = 1;
 227     p_block_out = p_sys->p_packetizer->pf_packetize(
 228         p_sys->p_packetizer, &p_block_in );
 229
 230     if( p_block_out == NULL )
 231     {
 232         msg_Dbg( p_demux, "did not sync on first block" );
 233         p_sys->b_initial_sync_failed = VLC_TRUE;
 234     }
 235     else
 236         p_sys->b_initial_sync_failed = VLC_FALSE;
 237
 238     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 239
 240     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 241         p_sys->i_xing_frame_samples )
 242     {
 243         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * I64C(8) *
 244             p_sys->p_packetizer->fmt_out.audio.i_rate /
 245             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 246     }
 247
 248     p_sys->p_block_in = p_block_in;
 249     p_sys->p_block_out = p_block_out;
 250
 251     /* */
 252     p_sys->p_packetizer->fmt_out.b_packetized = VLC_TRUE;
 253     p_sys->p_es = es_out_Add( p_demux->out,
 254                               &p_sys->p_packetizer->fmt_out);
 255     return VLC_SUCCESS;
 256 }
 257
 258 /*****************************************************************************
 259  * Demux: reads and demuxes data packets
 260  *****************************************************************************
 261  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 262  *****************************************************************************/
 263 static int Demux( demux_t *p_demux )
 264 {
 265     demux_sys_t *p_sys = p_demux->p_sys;
 266     block_t *p_block_in, *p_block_out;
 267     if( p_sys->b_start )
 268     {
 269         p_sys->b_start = VLC_FALSE;
 270         p_block_in = p_sys->p_block_in;
 271         p_sys->p_block_in = NULL;
 272         p_block_out = p_sys->p_block_out;
 273         p_sys->p_block_out = NULL;
 274     }
 275     else
 276     {
 277         if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) )
 278             == NULL )
 279         {
 280             return 0;
 281         }
 282         if( p_demux->p_sys->b_initial_sync_failed == VLC_TRUE )
 283         {
 284             p_block_in->i_pts = p_block_in->i_dts = 1;
 285             /* Only try to resync once */
 286             p_demux->p_sys->b_initial_sync_failed = 0;
 287         }
 288         else
 289             p_block_in->i_pts = p_block_in->i_dts = 0;
 290         p_block_out = p_sys->p_packetizer->pf_packetize(
 291             p_sys->p_packetizer, &p_block_in );
 292     }
 293
 294
 295     while( p_block_out )
 296     {
 297         while( p_block_out )
 298         {
 299             block_t *p_next = p_block_out->p_next;
 300
 301             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 302
 303             p_block_out->p_next = NULL;
 304             p_sys->i_pts = p_block_out->i_pts;
 305             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 306
 307             p_block_out = p_next;
 308         }
 309         p_block_out = p_sys->p_packetizer->pf_packetize(
 310             p_sys->p_packetizer, &p_block_in );
 311     }
 312     return 1;
 313 }
 314
 315 /*****************************************************************************
 316  * Close: frees unused data
 317  *****************************************************************************/
 318 static void Close( vlc_object_t * p_this )
 319 {
 320     demux_t     *p_demux = (demux_t*)p_this;
 321     demux_sys_t *p_sys = p_demux->p_sys;
 322
 323     DESTROY_PACKETIZER( p_sys->p_packetizer );
 324     if( p_sys->p_block_out ) block_Release( p_sys->p_block_out );
 325
 326     free( p_sys );
 327 }
 328
 329 /*****************************************************************************
 330  * Control:
 331  *****************************************************************************/
 332 static int Control( demux_t *p_demux, int i_query, va_list args )
 333 {
 334     demux_sys_t *p_sys  = p_demux->p_sys;
 335     int64_t *pi64;
 336     vlc_bool_t *pb_bool;
 337     int i_ret;
 338
 339     switch( i_query )
 340     {
 341         case DEMUX_HAS_UNSUPPORTED_META:
 342             pb_bool = (vlc_bool_t*)va_arg( args, vlc_bool_t* );
 343             *pb_bool = VLC_TRUE;
 344             return VLC_SUCCESS;
 345
 346         case DEMUX_GET_TIME:
 347             pi64 = (int64_t*)va_arg( args, int64_t * );
 348             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 349             return VLC_SUCCESS;
 350
 351         case DEMUX_SET_TIME:
 352             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 353              * needed for multi-input */
 354
 355         default:
 356             i_ret = demux2_vaControlHelper( p_demux->s, 0, -1,
 357                                             p_sys->i_bitrate_avg, 1, i_query,
 358                                             args );
 359             /* No bitrate, we can't have it precisely, but we can compute
 360              * a raw approximation with time/position */
 361             if( i_ret && i_query == DEMUX_GET_LENGTH &&!p_sys->i_bitrate_avg )
 362             {
 363                 float f_pos = (double)(uint64_t)( stream_Tell( p_demux->s ) ) /
 364                               (double)(uint64_t)( stream_Size( p_demux->s ) );
 365                 /* The first few seconds are guaranteed to be very whacky,
 366                  * don't bother trying ... Too bad */
 367                 if( f_pos < 0.01 ||
 368                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 369                     return VLC_EGENERIC;
 370
 371                 pi64 = (int64_t *)va_arg( args, int64_t * );
 372                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 373                 return VLC_SUCCESS;
 374             }
 375             if( !i_ret && p_sys->i_bitrate_avg > 0 &&
 376                 (i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME) )
 377             {
 378                 int64_t i_time = I64C(8000000) * stream_Tell(p_demux->s) /
 379                     p_sys->i_bitrate_avg;
 380
 381                 /* Fix time_offset */
 382                 if( i_time >= 0 ) p_sys->i_time_offset = i_time - p_sys->i_pts;
 383             }
 384             return i_ret;
 385     }
 386 }