VM conditional navigation

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  • VRYK
    Super Member
    Super Member
    • Jan 2009
    • 226

    VM conditional navigation

    In a PGC’s pre-commands I wish to direct playback to a given line dependant on the value in an SPRM register (# 8 which holds the highlighted button number). While I find numerous instances of commands conditional on a GPRM value, I have not found commands conditional on an SPRM value. Is this latter approach not normal practice – should a GPRM register be first set equal to the SPRM value ?
  • r0lZ
    Lord of Digital Video
    Lord of Digital Video
    • Mar 2004
    • 1508

    #2
    You're right. The designers of the DVD-Video standard have decided to make things complex without reason. So, you cannot use a SPRM in a condifional command, and you have to copy it first in a GPRM, as you guessed.

    It's really stupid, as it is theoretically possible to use the SPRM directly. It's just a flag to add in the byte that contains the SPRM or GPRM number in the binary command. That flag exists and is used in many commands when a GPRM or SPRM can be used, but it cannot be set in the condition of the conditional commands, although there is room for it. Why they decided to prohibit it is for me a great mystery!
    r0lZ
    PgcEdit homepage (hosted by VideoHelp)
    Unofficial mirror (in Poland)

    Comment

    • VRYK
      Super Member
      Super Member
      • Jan 2009
      • 226

      #3
      Many thanks for your confirmation. Indeed, the logic of the designers is hard to fathom; I guess one can only sigh “Les voies du Seigneur ….”.

      I would like to come back to the problem I had with cutting via VB a long blank which occurred between the end of images and then end of a cell. After having originally tried to edit the relevant episode PGC cell, I found that by acting on the relevant cell in the “Play All” PGC, I was able to split this and subsequently blank the newly-created cell.

      One thing which I left unresolved in this video was an audio track problem. There are two (English) audio tracks – track 0 being AC3 6-Channel and track 1 AC3 2-Channel. I wish to change the default from track 1 to track 0. In the main movie PGC’s pre-commands I inserted [51 00 00 80 00 00 00 00], but the default remains Track 1.

      Comment

      • r0lZ
        Lord of Digital Video
        Lord of Digital Video
        • Mar 2004
        • 1508

        #4
        Are you sure the command is executed, and thet there is no other SetSTN executed after that one?
        If you're not sure, post the pre-commands here.
        r0lZ
        PgcEdit homepage (hosted by VideoHelp)
        Unofficial mirror (in Poland)

        Comment

        • VRYK
          Super Member
          Super Member
          • Jan 2009
          • 226

          #5
          Yes, the command is being executed and it is the only pre-command in the PGC.

          Comment

          • r0lZ
            Lord of Digital Video
            Lord of Digital Video
            • Mar 2004
            • 1508

            #6
            In that case, that must work! What stream number displays the PgcEdit trace when the title is played?
            r0lZ
            PgcEdit homepage (hosted by VideoHelp)
            Unofficial mirror (in Poland)

            Comment

            • VRYK
              Super Member
              Super Member
              • Jan 2009
              • 226

              #7
              When the disque is loaded the SPRM value is 15, but the pre-command sets it to 0. The VLC player shows Track 2 by default whether the SPRM is 15 or 0. As mentioned earlier, PgcEdit shows Audio track 0 as 6-channel AC3 and track 1 as, 2-channel (the latter being very faint).

              Comment

              • r0lZ
                Lord of Digital Video
                Lord of Digital Video
                • Mar 2004
                • 1508

                #8
                Originally Posted by VRYK
                When the disque is loaded the SPRM value is 15, but the pre-command sets it to 0.
                So, when the title is running in trace mode, you see "0: en, unspecified (AC3)" in the virtual player panel of PgcEdit? If it's the case, that confirms that your authoring is correct and that VLC is not at all a DVD-Video standard compliant player.

                Or perhaps it has a function to overwrite the default audio when it finds that another audio track is theoretically better for your hardware. If it's the case, it should be possible to turn that option off.

                BTW, I never use VLC to verify the authoring of a DVD, because it has too many bugs and discrepancies. It's a good multimedia player, except for the DVDs.
                r0lZ
                PgcEdit homepage (hosted by VideoHelp)
                Unofficial mirror (in Poland)

                Comment

                • VRYK
                  Super Member
                  Super Member
                  • Jan 2009
                  • 226

                  #9
                  The trace log window shows:
                  Entering VTST 1 , 1 TTN 1 (1:31:54) Title 1
                  -- pre 1 : (SetSTN) Set Audio stream = 0
                  -> sprm(1:Audio stream number) = 0 (0x0000)
                  ******* Start playback VTST 1 , 1 TTN 1 (1:31:54) Title 1...

                  Or perhaps it has a function to overwrite the default audio<
                  I take it you are referring to the VLC player.

                  What would you recommend for playing DVDs instead of the VLC player ?

                  Comment

                  • r0lZ
                    Lord of Digital Video
                    Lord of Digital Video
                    • Mar 2004
                    • 1508

                    #10
                    Originally Posted by VRYK
                    The trace log window shows:
                    Entering VTST 1 , 1 TTN 1 (1:31:54) Title 1
                    -- pre 1 : (SetSTN) Set Audio stream = 0
                    -> sprm(1:Audio stream number) = 0 (0x0000)
                    ******* Start playback VTST 1 , 1 TTN 1 (1:31:54) Title 1...
                    Seems correct.

                    Originally Posted by VRYK
                    Or perhaps it has a function to overwrite the default audio<
                    I take it you are referring to the VLC player.
                    Yes, of course.

                    Originally Posted by VRYK
                    What would you recommend for playing DVDs instead of the VLC player ?
                    The most recent thread in this forum is (indirectly) on that subject: http://forum.digital-digest.com/f14/...ink-95292.html
                    r0lZ
                    PgcEdit homepage (hosted by VideoHelp)
                    Unofficial mirror (in Poland)

                    Comment

                    • VRYK
                      Super Member
                      Super Member
                      • Jan 2009
                      • 226

                      #11
                      Many thanks - I shall change my test player accordingly.

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