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 };
  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 false;
  92     }
  93     return 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  * Open: initializes demux structures
 117  *****************************************************************************/
 118 static int Open( vlc_object_t * p_this )
 119 {
 120     demux_t     *p_demux = (demux_t*)p_this;
 121     demux_sys_t *p_sys;
 122     bool   b_forced = false;
 123
 124     uint32_t     header;
 125     const uint8_t     *p_peek;
 126
 127     if( demux_IsPathExtension( p_demux, ".mp3" ) )
 128         b_forced = 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         bool b_ok = 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 = 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 = true;
 157
 158     /* Load the mpeg audio packetizer */
 159     INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );
 160     es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );
 161     LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );
 162
 163     /* Xing header */
 164     if( HeaderCheck( header ) )
 165     {
 166         int i_xing, i_skip;
 167         const uint8_t *p_xing;
 168
 169         if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )
 170             return VLC_SUCCESS; /* No header */
 171
 172         if( MPGA_VERSION( header ) == 0 )
 173         {
 174             i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;
 175         }
 176         else
 177         {
 178             i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;
 179         }
 180
 181         if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )
 182         {
 183             unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );
 184
 185             p_xing += i_skip + 8;
 186             i_xing -= i_skip + 8;
 187
 188             i_skip = 0;
 189             if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */
 190             {
 191                 p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );
 192                 i_skip += 4;
 193             }
 194             if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */
 195             {
 196                 p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );
 197                 i_skip += 4;
 198             }
 199             if( i_flags&0x04 )   /* XING_TOC */
 200             {
 201                 i_skip += 100;
 202             }
 203
 204             // FIXME: doesn't return the right bitrage average, at least
 205             // with some MP3's
 206             if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */
 207             {
 208                 p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );
 209                 msg_Dbg( p_demux, "xing vbr value present (%d)",
 210                          p_sys->i_xing_bitrate_avg );
 211             }
 212
 213             if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )
 214             {
 215                 p_sys->i_xing_frame_samples = mpga_frame_samples( header );
 216                 msg_Dbg( p_demux, "xing frames&bytes value present "
 217                          "(%d bytes, %d frames, %d samples/frame)",
 218                          p_sys->i_xing_bytes, p_sys->i_xing_frames,
 219                          p_sys->i_xing_frame_samples );
 220             }
 221         }
 222     }
 223
 224     if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&
 225         p_sys->i_xing_frame_samples )
 226     {
 227         p_sys->i_bitrate_avg = p_sys->i_xing_bytes * INT64_C(8) *
 228             p_sys->p_packetizer->fmt_out.audio.i_rate /
 229             p_sys->i_xing_frames / p_sys->i_xing_frame_samples;
 230     }
 231
 232     return VLC_SUCCESS;
 233 }
 234
 235 /*****************************************************************************
 236  * Demux: reads and demuxes data packets
 237  *****************************************************************************
 238  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 239  *****************************************************************************/
 240 static int Demux( demux_t *p_demux )
 241 {
 242     demux_sys_t *p_sys = p_demux->p_sys;
 243     block_t *p_block_in, *p_block_out;
 244
 245     if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )
 246     {
 247         return 0;
 248     }
 249
 250     p_block_in->i_pts = p_block_in->i_dts = p_sys->b_start || p_sys->b_initial_sync_failed ? 1 : 0;
 251     p_sys->b_initial_sync_failed = p_sys->b_start; /* Only try to resync once */
 252
 253     while( ( p_block_out = p_sys->p_packetizer->pf_packetize( p_sys->p_packetizer, &p_block_in ) ) )
 254     {
 255         p_sys->b_initial_sync_failed = false;
 256         while( p_block_out )
 257         {
 258             block_t *p_next = p_block_out->p_next;
 259
 260             if( !p_sys->p_es )
 261             {
 262                 p_sys->p_packetizer->fmt_out.b_packetized = true;
 263                 p_sys->p_es = es_out_Add( p_demux->out,
 264                                           &p_sys->p_packetizer->fmt_out);
 265
 266                 if( p_sys->i_bitrate_avg <= 0 )
 267                     p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;
 268             }
 269
 270             p_sys->i_pts = p_block_out->i_pts;
 271
 272             /* Correct timestamp */
 273             p_block_out->i_pts += p_sys->i_time_offset;
 274             p_block_out->i_dts += p_sys->i_time_offset;
 275
 276             es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
 277
 278             es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
 279
 280             p_block_out = p_next;
 281         }
 282     }
 283
 284     if( p_sys->b_initial_sync_failed )
 285         msg_Dbg( p_demux, "did not sync on first block" );
 286     p_sys->b_start = false;
 287     return 1;
 288 }
 289
 290 /*****************************************************************************
 291  * Close: frees unused data
 292  *****************************************************************************/
 293 static void Close( vlc_object_t * p_this )
 294 {
 295     demux_t     *p_demux = (demux_t*)p_this;
 296     demux_sys_t *p_sys = p_demux->p_sys;
 297
 298     DESTROY_PACKETIZER( p_sys->p_packetizer );
 299
 300     free( p_sys );
 301 }
 302
 303 /*****************************************************************************
 304  * Control:
 305  *****************************************************************************/
 306 static int Control( demux_t *p_demux, int i_query, va_list args )
 307 {
 308     demux_sys_t *p_sys  = p_demux->p_sys;
 309     int64_t *pi64;
 310     bool *pb_bool;
 311     int i_ret;
 312     va_list args_save;
 313
 314     va_copy ( args_save, args );
 315
 316     switch( i_query )
 317     {
 318         case DEMUX_HAS_UNSUPPORTED_META:
 319             pb_bool = (bool*)va_arg( args, bool* );
 320             *pb_bool = true;
 321             return VLC_SUCCESS;
 322
 323         case DEMUX_GET_TIME:
 324             pi64 = (int64_t*)va_arg( args, int64_t * );
 325             *pi64 = p_sys->i_pts + p_sys->i_time_offset;
 326             return VLC_SUCCESS;
 327
 328         case DEMUX_GET_LENGTH:
 329             i_ret = demux_vaControlHelper( p_demux->s, 0, -1,
 330                                             p_sys->i_bitrate_avg, 1, i_query,
 331                                             args );
 332             /* No bitrate, we can't have it precisely, but we can compute
 333              * a raw approximation with time/position */
 334             if( i_ret && !p_sys->i_bitrate_avg )
 335             {
 336                 float f_pos = (double)(uint64_t)( stream_Tell( p_demux->s ) ) /
 337                               (double)(uint64_t)( stream_Size( p_demux->s ) );
 338                 /* The first few seconds are guaranteed to be very whacky,
 339                  * don't bother trying ... Too bad */
 340                 if( f_pos < 0.01 ||
 341                     (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )
 342                     return VLC_EGENERIC;
 343
 344                 pi64 = (int64_t *)va_arg( args_save, int64_t * );
 345                 *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;
 346                 return VLC_SUCCESS;
 347             }
 348             va_end( args_save );
 349             return i_ret;
 350
 351         case DEMUX_SET_TIME:
 352             /* FIXME TODO: implement a high precision seek (with mp3 parsing)
 353              * needed for multi-input */
 354         default:
 355             i_ret = demux_vaControlHelper( p_demux->s, 0, -1,
 356                                             p_sys->i_bitrate_avg, 1, i_query,
 357                                             args );
 358             if( !i_ret && p_sys->i_bitrate_avg > 0 &&
 359                 (i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME) )
 360             {
 361                 int64_t i_time = INT64_C(8000000) * stream_Tell(p_demux->s) /
 362                     p_sys->i_bitrate_avg;
 363
 364                 /* Fix time_offset */
 365                 if( i_time >= 0 )
 366                     p_sys->i_time_offset = i_time - p_sys->i_pts;
 367             }
 368             return i_ret;
 369     }
 370 }