[MPlayer-dev-eng] DVD navigation again

[Kees Cook]

On Fri, Mar 29, 2002 at 12:55:43AM +0100, Arpi wrote:
> sorry, i've never seen dvd menus :)
> i should try ogle, afaik it already supports them...

Yes, which is what got me started on this.  :P  I got my first ever DVD a 
few days ago, played around with regular -dvd playing in MPlayer, and then 
used ogle, and it did all the navigation just fine.

> > navigation.  I've been trying to read through the DVD specs and understand
> hmm, what specs do you have?

They're not great, but here:
http://members.aol.com/mpucoder/DVD/

It doesn't have a "how to use", but it does seem to be a good reference.

> last time (week ago) when i talked about dvdnav with Guenter (xine author)
> he said no specs available on dvd navigation for opensource developers.

Yeah.  There are a few locations where things are not obvious, and so far, 
libdvdnav just guesses based on reports of behavior from different DVDs.

> the biggest problem with dvdnav is the still image detection. afaik it fails
> to detect them all time and xine now uses some heuristics-hack to recognize
> them in the mpeg decoder. i don't want to see such hack in mplayer code,
> it was the main reason of refusing the dvdnav patch first time.
> now i applied, but still don't know how to detect still images in stable,
> compatible, clean way. i'm sure the official dvd spects explain the real
> way.

That's one of the things that is broken right now.  I only have one DVD to
test with, and all the menus seem to be video rather than still.  As for
the stills right now, they just shoot right by.  Instead of a copyright
warning all I saw was a flash of red.  ;P

> hmm. so we should hack spudec to handle these...

Possibly.  After discovering what SPUs were, I spent time looking through 
the dvdnav library.  I think to do it right, large portions of dvdnav will 
need to be rewritten.  The VM state machine is what we're interested in.  
And it will need to feed control information to MPlayer somehow.  "play 
mpg from here", "use this audio now", etc.

Before I go any further I want to familiarize myself with how regular DVD 
playback is being done in MPlayer, and see if a control system can be 
written on top of it, and add a "navdemux" or something to pull nav 
packets from.  Not sure, just thinking out loud here.

-- 
Kees Cook                                            @outflux.net