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/vlc.h>
  34 #include <vlc_demux.h>
  35 #include <vlc_codec.h>
  36 #include <vlc_input.h>
  37
  38 #define MPGA_PACKET_SIZE 1024
  39
  40 /*****************************************************************************
  41  * Module descriptor
  42  *****************************************************************************/
  43 static int  Open ( vlc_object_t * );
  44 static void Close( vlc_object_t * );
  45
  46 vlc_module_begin();
  47     set_category( CAT_INPUT );
  48     set_subcategory( SUBCAT_INPUT_DEMUX );
  49     set_description( _("MPEG audio / MP3 demuxer" ) );
  50     set_capability( "demux2", 100 );
  51     set_callbacks( Open, Close );
  52     add_shortcut( "mpga" );
  53     add_shortcut( "mp3" );
  54 vlc_module_end();
  55
  56 /*****************************************************************************
  57  * Local prototypes
  58  *****************************************************************************/
  59 static int Demux  ( demux_t * );
  60 static int Control( demux_t *, int, va_list );
  61
  62 struct demux_sys_t
  63 {
  64     es_out_id_t *p_es;
  65
  66     vlc_bool_t  b_start;
  67     decoder_t   *p_packetizer;
  68
  69     mtime_t     i_pts;
  70     mtime_t     i_time_offset;
  71     int         i_bitrate_avg;  /* extracted from Xing header */
  72
  73     vlc_bool_t b_initial_sync_failed;
  74
  75     int i_xing_frames;
  76     int i_xing_bytes;
  77     int i_xing_bitrate_avg;
  78     int i_xing_frame_samples;
  79     block_t *p_block_in, *p_block_out;
  80 };
  81
  82 static int HeaderCheck( uint32_t h )
  83 {
  84     if( ((( h >> 21 )&0x07FF) != 0x07FF )   /* header sync */
  85         || (((h >> 17)&0x03) == 0 )         /* valid layer ?*/
  86         || (((h >> 12)&0x0F) == 0x0F )
  87         || (((h >> 12)&0x0F) == 0x00 )      /* valid bitrate ? */
  88         || (((h >> 10) & 0x03) == 0x03 )    /* valide sampling freq ? */
  89         || ((h & 0x03) == 0x02 ))           /* valid emphasis ? */
  90     {
  91         return VLC_FALSE;
  92     }
  93     return VLC_TRUE;
  94 }
  95
  96 #define MPGA_VERSION( h )   ( 1 - (((h)>>19)&0x01) )
  97 #define MPGA_LAYER( h )     ( 3 - (((h)>>17)&0x03) )
  98 #define MPGA_MODE(h)        (((h)>> 6)&0x03)
  99
 100 static int mpga_frame_samples( uint32_t h )
 101 {
 102     switch( MPGA_LAYER(h) )
 103     {
 104         case 0:
 105             return 384;
 106         case 1:
 107             return 1152;
 108         case 2:
 109             return MPGA_VERSION(h) ? 576 : 1152;
 110         default:
 111             return 0;
 112     }
 113 }
 114
 115
 116 /*****************************************************************************
 117  * Open: initializes demux structures
 118  *****************************************************************************/
 119 static int Open( vlc_object_t * p_this )
 120 {
 121     demux_t     *p_demux = (demux_t*)p_this;
 122     demux_sys_t *p_sys;
 123     vlc_bool_t   b_forced = VLC_FALSE;
 124
 125     uint32_t     header;
 126     const uint8_t     *p_peek;
 127     block_t     *p_block_in, *p_block_out;
 128
 129     if( demux2_IsPathExtension( p_demux, ".mp3" ) )
 130         b_forced = VLC_TRUE;
 131
 132     if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
 133
 134     if( !HeaderCheck( header = GetDWBE( p_peek ) ) )
 135     {
 136         vlc_bool_t b_ok = VLC_FALSE;
 137         int i_peek;
 138
 139         if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;
 140
 141         i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );
 142         while( i_peek > 4 )
 143         {
 144             if( HeaderCheck( header = GetDWBE( p_peek ) ) )
 145             {
 146                 b_ok = VLC_TRUE;
 147                 break;
 148             }
 149             p_peek += 1;
 150             i_peek -= 1;
 151         }
 152         if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;
 153     }
 154
 155     DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
 156     memset( p_sys, 0, sizeof( demux_sys_t ) );
 157     p_sys->p_es = 0;
 158     p_sys->b_start = VLC_TRUE;
 159
 160     /* Load the mpeg audio packetizer */
 161     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 162     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 163     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 164
 165     /* Xing header */
 166     if( HeaderCheck( header ) )
 167     {
 168         int i_xing, i_skip;
 169         const uint8_t *p_xing;
 170
 171         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 172             return VLC_SUCCESS; /* No header */
 173
 174         if( MPGA_VERSION( header ) == 0 )
 175         {
 176             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 177         }
 178         else
 179         {
 180             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 181         }
 182
 183         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 184         {
 185             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 186
 187             p_xing += i_skip + 8;
 188             i_xing -= i_skip + 8;
 189
 190             i_skip = 0;
 191             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 192             {
 193                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 194                 i_skip += 4;
 195             }
 196             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 197             {
 198                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 199                 i_skip += 4;
 200             }
 201             if( i_flags&0x04 )   /* XING_TOC */
 202             {
 203                 i_skip += 100;
 204             }
 205
 206             // FIXME: doesn't return the right bitrage average, at least
 207             // with some MP3's
 208             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 209             {
 210                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 211                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 212                          p_sys->i_xing_bitrate_avg );
 213             }
 214
 215             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 216             {
 217                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 218                 msg_Dbg( p_demux, "xing frames&bytes value present "
 219                          "(%d bytes, %d frames, %d samples/frame)",
 220                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 221                          p_sys->i_xing_frame_samples );
 222             }
 223         }
 224     }
 225
 226     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 227     {
 228         return VLC_EGENERIC;
 229     }
 230     p_block_in->i_pts = p_block_in->i_dts = 1;
 231     p_block_out = p_sys->p_packetizer->pf_packetize(
 232         p_sys->p_packetizer, &p_block_in );
 233
 234     if( p_block_out == NULL )
 235     {
 236         msg_Dbg( p_demux, "did not sync on first block" );
 237         p_sys->b_initial_sync_failed = VLC_TRUE;
 238     }
 239     else
 240         p_sys->b_initial_sync_failed = VLC_FALSE;
 241
 242     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 243
 244     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 245         p_sys->i_xing_frame_samples )
 246     {
 247         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * I64C(8) *
 248             p_sys->p_packetizer->fmt_out.audio.i_rate /
 249             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 250     }
 251
 252     p_sys->p_block_in = p_block_in;
 253     p_sys->p_block_out = p_block_out;
 254
 255     /* */
 256     p_sys->p_packetizer->fmt_out.b_packetized = VLC_TRUE;
 257     p_sys->p_es = es_out_Add( p_demux->out,
 258                               &p_sys->p_packetizer->fmt_out);
 259     return VLC_SUCCESS;
 260 }
 261
 262 /*****************************************************************************
 263  * Demux: reads and demuxes data packets
 264  *****************************************************************************
 265  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 266  *****************************************************************************/
 267 static int Demux( demux_t *p_demux )
 268 {
 269     demux_sys_t *p_sys = p_demux->p_sys;
 270     block_t *p_block_in, *p_block_out;
 271     if( p_sys->b_start )
 272     {
 273         p_sys->b_start = VLC_FALSE;
 274         p_block_in = p_sys->p_block_in;
 275         p_sys->p_block_in = NULL;
 276         p_block_out = p_sys->p_block_out;
 277         p_sys->p_block_out = NULL;
 278     }
 279     else
 280     {
 281         if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) )
 282             == NULL )
 283         {
 284             return 0;
 285         }
 286         if( p_demux->p_sys->b_initial_sync_failed == VLC_TRUE )
 287         {
 288             p_block_in->i_pts = p_block_in->i_dts = 1;
 289             /* Only try to resync once */
 290             p_demux->p_sys->b_initial_sync_failed = 0;
 291         }
 292         else
 293             p_block_in->i_pts = p_block_in->i_dts = 0;
 294         p_block_out = p_sys->p_packetizer->pf_packetize(
 295             p_sys->p_packetizer, &p_block_in );
 296     }
 297
 298
 299     while( p_block_out )
 300     {
 301         while( p_block_out )
 302         {
 303             block_t *p_next = p_block_out->p_next;
 304
 305             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 306
 307             p_block_out->p_next = NULL;
 308             p_sys->i_pts = p_block_out->i_pts;
 309             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 310
 311             p_block_out = p_next;
 312         }
 313         p_block_out = p_sys->p_packetizer->pf_packetize(
 314             p_sys->p_packetizer, &p_block_in );
 315     }
 316     return 1;
 317 }
 318
 319 /*****************************************************************************
 320  * Close: frees unused data
 321  *****************************************************************************/
 322 static void Close( vlc_object_t * p_this )
 323 {
 324     demux_t     *p_demux = (demux_t*)p_this;
 325     demux_sys_t *p_sys = p_demux->p_sys;
 326
 327     DESTROY_PACKETIZER( p_sys->p_packetizer );
 328     if( p_sys->p_block_out ) block_Release( p_sys->p_block_out );
 329
 330     free( p_sys );
 331 }
 332
 333 /*****************************************************************************
 334  * Control:
 335  *****************************************************************************/
 336 static int Control( demux_t *p_demux, int i_query, va_list args )
 337 {
 338     demux_sys_t *p_sys  = p_demux->p_sys;
 339     int64_t *pi64;
 340     vlc_bool_t *pb_bool;
 341     int i_ret;
 342     va_list args_save;
 343
 344     va_copy ( args_save, args );
 345
 346     switch( i_query )
 347     {
 348         case DEMUX_HAS_UNSUPPORTED_META:
 349             pb_bool = (vlc_bool_t*)va_arg( args, vlc_bool_t* );
 350             *pb_bool = VLC_TRUE;
 351             return VLC_SUCCESS;
 352
 353         case DEMUX_GET_TIME:
 354             pi64 = (int64_t*)va_arg( args, int64_t * );
 355             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 356             return VLC_SUCCESS;
 357
 358         case DEMUX_SET_TIME:
 359             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 360              * needed for multi-input */
 361
 362         case DEMUX_GET_LENGTH:
 363             i_ret = demux2_vaControlHelper( p_demux->s, 0, -1,
 364                                             p_sys->i_bitrate_avg, 1, i_query,
 365                                             args );
 366             /* No bitrate, we can't have it precisely, but we can compute
 367              * a raw approximation with time/position */
 368             if( i_ret && !p_sys->i_bitrate_avg )
 369             {
 370                 float f_pos = (double)(uint64_t)( stream_Tell( p_demux->s ) ) /
 371                               (double)(uint64_t)( stream_Size( p_demux->s ) );
 372                 /* The first few seconds are guaranteed to be very whacky,
 373                  * don't bother trying ... Too bad */
 374                 if( f_pos < 0.01 ||
 375                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 376                     return VLC_EGENERIC;
 377
 378                 pi64 = (int64_t *)va_arg( args_save, int64_t * );
 379                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 380                 return VLC_SUCCESS;
 381             }
 382             va_end( args_save );
 383             return i_ret;
 384
 385         default:
 386             i_ret = demux2_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 = 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 }