[DVDnav-discuss] [PATCH] "dvdnav_jump_to_sector" as an alternative to "dvdnav_time_search" (REV 5: combined args to structs)

Joakim Plate elupus at ecce.se
Thu Apr 19 09:50:01 CEST 2012

> 1) Open up the VOB to find out the exact timestamp for VOBU 27.
>    Unfortunately this would require even more code on top of what I
> wrote. I looked at this last year, and I don't think there is code in
> dvdread to easily extract the timestamp for a VOBU from a VOB.
>    Also, I would think that there is a performance hit in doing a
> disc-read of VOBU 27 to get its timestamp. An earlier version of my
> patch was incorrectly reading the IFO on each jump, and this extra
> "read" was noticeable to Roger.

The first data at a vob unit is a NAV packet. This contains time
information for requested vob unit, AS WELL as back time skip
information both back and forward in time, contained in the vobu_sri_t
structure. Doing a read of this single sector won't hurt much I think
(you are going to read it the moment you request playback anyway).

I think a tmap search to a vobunit close to the requested time, read
NAV packet, use the info in vobu_sri_t to figure out how to get a more
exact location jump there is what is the best approach.

But i'd like to add that i think it's better we add the parameter to
the API even if it's currently won't be implemented. That way the API
won't need to be changed to add support.

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