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