Conoscere il numero di titoli e di capitoli presenti in un DVD video con le funzioni del API di libdvdread

Usando alcune funzioni esterne della libreria "libdvdread" è possibile conoscere quanti titoli e quanti capitoli sono presenti un un disco DVD video.

Per fruire in Gambas delle risorse di libdvdread bisognerà avere installata nel sistema la libreria condivisa: "libdvdread.so.7.0.0".

Mostriamo di seguito un breve codice esemplificativo:

Library "libdvdread:7.0.0"

Public Struct ifo_handle_t
  file_ As Pointer
  vmgi_mat As Pointer
  tt_srpt As Pointer
  first_play_pgc As Pointer
  ptl_mait As Pointer
  vts_atrt As Pointer
  txtdt_mgi As Pointer
  pgci_ut As Pointer
  menu_c_adt As Pointer
  menu_vobu_admap As Pointer
  vtsi_mat As Pointer
  vts_ptt_srpt As Pointer
  vts_pgcit As Pointer
  vts_tmapt As Pointer
  vts_c_adt As Pointer
  vts_vobu_admap As Pointer
End Struct

Public Struct tt_srpt_t
  nr_of_srpts As Short
  zero_1 As Short
  last_byte As Integer
  title As Pointer
End Struct

Public Struct title_info_t
  pb_ty As Byte
  nr_of_angles As Byte
  nr_of_ptts As Short
  parental_id As Short
  title_set_nr As Byte
  vts_ttn As Byte
  title_set_sector As Integer
End Struct

' dvd_reader_t* DVDOpen (const char * path)
' Opens a block device of a DVD-ROM file, or an image file, or a directory name for a mounted DVD or HD copy of a DVD.
Private Extern DVDOpen(path As String) As Pointer

' ifo_handle_t * ifoOpen (dvd_reader_t *dvd, int title)
' Opens an IFO and reads in all the data for the IFO file corresponding to the given title.
Private Extern ifoOpen(dvd_reader_t As Pointer, title As Integer) As Ifo_handle_t

' void ifoClose(ifo_handle_t * ifofile)
' Cleans up the IFO information.
Private Extern ifoClose(ifofile As Ifo_handle_t)

' void DVDClose (dvd_reader_t *dvd)
' Closes and cleans up the DVD reader object.
Private Extern DVDClose(dvd_reader_t As Pointer)


Public Sub Main()

 Dim dvd As Pointer
 Dim ifo As Ifo_handle_t
 Dim tt_srpt As Tt_srpt_t
 Dim title As Title_info_t
 Dim i as Integer
  
' Apre il disco. E' necessario individuare l'esatto device !
 dvd = DVDOpen("/dev/dvd")   ' ...oppure in taluni casi potrebbe essere, ad esempio, "/dev/sr0"
 If dvd == 0 Then Error.Raise("Impossibile aprire il DVD: nessun dvd trovato !")
       
' Carica il gestore video per cercare informazioni relative ai titoli sul disco:
 ifo = ifoOpen(dvd, 0)
 If IsNull(ifo) Then
   DVDClose(dvd)
   Error.Raise("Impossibile aprire il gestore video e leggere il file principale IFO !")
 Endif
 
 tt_srpt = ifo.tt_srpt   ' NOTA
 Print "Sono presenti nel DVD-Video "; tt_srpt.nr_of_srpts; " titoli.\n"
 
 For i = 0 To tt_srpt.nr_of_srpts - 1
   Print "TITOLO "; i + 1; ":"
      title = tt_srpt.title + (i * 12)
      Print "   in VTS: "; title.title_set_nr; " [TTN "; title.vts_ttn; "]"
      Print "   il titolo ha "; title.nr_of_ptts; " capitoli\n"
 Next 
  
' Va in chiusura:
 ifoClose(ifo)
 DVDClose(dvd)
   
End