width   = 1024 * 1024
bytes   = 32 * width;
p       = new BYTE[ bytes ];

ID = n * width * 8 + bit;
p[ID] |= ( 1 << ( ID % 8 ) );

p[ID] &= ~( 1 << ( ID % 8 ) );

num_channels = 32;
labels       = new INT[ num_channels ];
width        = 1024 * 1024; /* один МБайт */
p            = new BYTE[ num_channels * width ];
...
for( lbl = 0 ; lbl < num_labels ; ++lbl ){
  for( i = 0 ; i < num_channels ; ++i ){
    if( labels[i] == lbl ){
      set_label_array( lbl, p + i * width );
    }
  }
}