after info about changing TTN conventions

[acid_kewpie]

Hi, i'm writing a dvd ripper front end for linux http://acidrip.thirtythreeandathird.net and having to write a secondary app to parse the structure of a dvd in a really really obivious adn readble format, so I need to find the length of each track in turn, not just the lengths of each TTN.

My app works great most of the time, but a couple of times i've had DVD's where the actual video stream is in a different TTN to the on it starts at (from video_ts.ifo). Now the first cell of the start TTN points to the next TTN, but i want to make sure i'm getting this right.. what are the possible conventions that could happen? can t be split over mupltiple TTN's? The total length of the first TTN has always been 0 so far, with the actaul length i need to get out being in the second TTN. is this the way it will always be? i'm just after a little explanation of what's possible around this area, and such what i realistically need to support in my software

thanks

chris
<edit>for below.. yeah i couldn't really pick a forum that really suited my needs... i mod linuxquestions.org and that always pisses me off... soz</edit>

[TRILIGHT]

@acid: This is a more advanced authoring question so I am going to move it to the advanced section and you may get more help.

@Mods: I think there is a better chance of this person getting help in the IFOedit forum but since this isn't really an IFOedit question, I'm moving to "Advanced Authoring".

[acid_kewpie]

right, i've been looking through various dvd sites and source code, and i've a few queries based around my question

now, my knowledge of the sturcture is based on libdvdread for linux, so mightn't overlap too well, but we have a route through this data structure as such:

video_ts.ifo->tt_srpt->title[i].title_set_nr
video_ts.ifo->tt_srpt->title[i].vts_ttn

these two seem to relate to the vts and ttn location of each title, i. However there is also a different setup, present in each vts_xx_x.ifo which is

vts_xx_x.ifo->vts_ptt_srpt->title[i].ptt[i].pgcn
vts_xx_x.ifo->vts_ptt_srpt->title[i].ptt[i].pgn

this second part of the data structure points to the individual cells (pgcn = program chain number i think..) of each title, but the situation I'm seeing is that these few dvd's i'm trying to accomodate, this pgn code (Program Number i think) relates to the actual ttn in the ifo where the video actaully IS. This contrasts with the easier first version where the video data is not always there. And with another BUT... the title[i] in the second part is (i believe) only the number of the video stream in the ifo file itself, and not the actual title number on the dvd, and i'm unable to see how this little picture pieces itself together.

i'd be seriously grateful for any light that can be shed in my direction.