libhb/demuxmpeg.c

   1 /* $Id: demuxmpeg.c,v 1.4 2004/10/19 23:11:36 titer Exp $
   2
   3    This file is part of the HandBrake source code.
   4    Homepage: <http://handbrake.m0k.org/>.
   5    It may be used under the terms of the GNU General Public License. */
   6
   7 #include "hb.h"
   8
   9 /* Basic MPEG demuxer, only works with DVDs (2048 bytes packets) */
  10
  11 int hb_demux_ps( hb_buffer_t * buf_ps, hb_list_t * list_es )
  12 {
  13     hb_buffer_t * buf_es;
  14     int           pos;
  15
  16     pos = 0;
  17
  18 #define d (buf_ps->data)
  19
  20     /* pack_header */
  21     if( d[pos] != 0 || d[pos+1] != 0 ||
  22         d[pos+2] != 0x1 || d[pos+3] != 0xBA )
  23     {
  24         hb_log( "hb_demux_ps: not a PS packet (%02x%02x%02x%02x)",
  25                 d[pos], d[pos+1], d[pos+2], d[pos+3] );
  26         return 0;
  27     }
  28     pos += 4;                    /* pack_start_code */
  29     pos += 9;                    /* pack_header */
  30     pos += 1 + ( d[pos] & 0x7 ); /* stuffing bytes */
  31
  32     /* system_header */
  33     if( d[pos] == 0 && d[pos+1] == 0 &&
  34         d[pos+2] == 0x1 && d[pos+3] == 0xBB )
  35     {
  36         int header_length;
  37
  38         pos           += 4; /* system_header_start_code */
  39         header_length  = ( d[pos] << 8 ) + d[pos+1];
  40         pos           += 2 + header_length;
  41     }
  42
  43     /* pes */
  44     while( pos + 6 < buf_ps->size &&
  45            d[pos] == 0 && d[pos+1] == 0 && d[pos+2] == 0x1 )
  46     {
  47         int      id;
  48         int      pes_packet_length;
  49         int      pes_packet_end;
  50         int      pes_header_d_length;
  51         int      pes_header_end;
  52         int      has_pts;
  53         int64_t  pts = -1;
  54
  55         pos               += 3;               /* packet_start_code_prefix */
  56         id           = d[pos];
  57         pos               += 1;
  58
  59         pes_packet_length  = ( d[pos] << 8 ) + d[pos+1];
  60         pos               += 2;               /* pes_packet_length */
  61         pes_packet_end     = pos + pes_packet_length;
  62
  63         if( id != 0xE0 && id != 0xBD &&
  64             ( id & 0xC0 ) != 0xC0  )
  65         {
  66             /* Not interesting */
  67             pos = pes_packet_end;
  68             continue;
  69         }
  70
  71         has_pts             = ( ( d[pos+1] >> 6 ) & 0x2 ) ? 1 : 0;
  72         pos               += 2;               /* Required headers */
  73
  74         pes_header_d_length  = d[pos];
  75         pos                    += 1;
  76         pes_header_end          = pos + pes_header_d_length;
  77
  78         if( has_pts )
  79         {
  80             pts = ( ( ( (uint64_t) d[pos] >> 1 ) & 0x7 ) << 30 ) +
  81                   ( d[pos+1] << 22 ) +
  82                   ( ( d[pos+2] >> 1 ) << 15 ) +
  83                   ( d[pos+3] << 7 ) +
  84                   ( d[pos+4] >> 1 );
  85         }
  86
  87         pos = pes_header_end;
  88
  89         if( id == 0xBD )
  90         {
  91             id |= ( d[pos] << 8 );
  92             if( ( id & 0xF0FF ) == 0x80BD ) /* A52 */
  93             {
  94                 pos += 4;
  95             }
  96             else if( ( id & 0xE0FF ) == 0x20BD || /* SPU */
  97                      ( id & 0xF0FF ) == 0xA0BD )  /* LPCM */
  98             {
  99                 pos += 1;
 100             }
 101         }
 102
 103         /* Sanity check */
 104         if( pos >= pes_packet_end )
 105         {
 106             pos = pes_packet_end;
 107             continue;
 108         }
 109
 110         /* Here we hit we ES payload */
 111         buf_es = hb_buffer_init( pes_packet_end - pos );
 112
 113         buf_es->id       = id;
 114         buf_es->start    = pts;
 115         if (id == 0xE0) {
 116             // Consume a chapter break, and apply it to the ES.
 117             buf_es->new_chap = buf_ps->new_chap;
 118             buf_ps->new_chap = 0;
 119         }
 120         memcpy( buf_es->data, d + pos, pes_packet_end - pos );
 121
 122         hb_list_add( list_es, buf_es );
 123
 124         pos = pes_packet_end;
 125     }
 126
 127 #undef d
 128
 129     return 1;
 130 }