[Matroska-devel] Spec Change (chapter start time)
steve.lhomme at free.fr
Sat Jan 8 18:00:29 CET 2005
Steve Lhomme a écrit :
> So, is it OK to remove the mandatory flag for ChapterTimeStart ?
> I'm modified DMX to keep most of the start timecodes. But I had to
> remove the PTT level because it's just a seek point. I'm not sure if I
> can remove it totally or I have to take it back with some more changes
> in the code... Actually it's one element which StartTime is vital, but
> I'm not sure it's needed. I'll check if there are DVD commands relating
> to the PTT level, otherwise it will be totally dropped...
> Also another thing we need is a better identification of segments. For
> example the VMG segment (first used when you enter a DVD) usually have a
> command JumpTT # (jump to title # x). That means jumping to another
> segment. But so far we don't know how to map the title/domain to a
> meaningfull element in Matroska. The Segment UID is an ID that should
> unique over a lot (global) of Matroska files. It could work, but only if
> you modify the value in the DVD command. IMO, that's not the way to go.
> We should have a better way to map the domain to an ID in the Segment
> Info. Hopefully something that would not be DVD specific, but more general.
> Comments are welcomed !
PS: It has been decided that for infinite still frames we will use a
"custom" command, using our own Chapter Codec. But we need to define it
now, so that I can add it to DMX (for the moment it outputs something
with a big TODO).
What kind of command should it be ?
- loop this ChapterAtom infinitely
- loop this ChapterAtom a given number of time (-1 = infinite)
- jump to a given timecode
I prefer option #2
Also how are we going to store our commands ? A statis struct-like
format ? Or something EBML like ? With the command ID, the length of the
command and the command data...
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