Visualizza wikitesto di 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
 
 <FONT color=gray>' ''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.''</font>
 Private Extern DVDOpen(path As String) As Pointer
 
 <FONT color=gray>' ''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.''</font>
 Private Extern ifoOpen(dvd_reader_t As Pointer, title As Integer) As Ifo_handle_t
 
 <FONT color=gray>' ''void ifoClose(ifo_handle_t * ifofile)''
 ' ''Cleans up the IFO information.''</font>
 Private Extern ifoClose(ifofile As Ifo_handle_t)
 
 <FONT color=gray>' ''void DVDClose (dvd_reader_t *dvd)''
 ' ''Closes and cleans up the DVD reader object.''</font>
 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
   
 <FONT color=gray>' ''Apre il disco. E' necessario individuare l'esatto device !''</font>
  dvd = DVDOpen("/dev/dvd")   <FONT color=gray>' ''...oppure in taluni casi potrebbe essere, ad esempio, "/dev/sr0"''</font>
  If dvd == 0 Then Error.Raise("Impossibile aprire il DVD: nessun dvd trovato !")
        
 <FONT color=gray>' ''Carica il gestore video per cercare informazioni relative ai titoli sul disco:''</font>
  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   <FONT color=gray>' ''NOTA''</font>
  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 
   
 <FONT color=gray>' ''Va in chiusura:''</font>
  ifoClose(ifo)
  DVDClose(dvd)
    
 '''End'''