[DVDnav-discuss] question regarding data coming from libdvdnav

[Sergey 'Jin' Bostandzhyan]

On Fri, Nov 21, 2008 at 10:04:18AM +0100, Nico Sabbi wrote:
> > I can only say the time that the player is printing on the TV, as I
> > mentioned in one of the previous posts I tried playing the stream
> > twice. The first time it crashed after about 34 seconds (0:0:34),
> > the second time it crashed after about 57 seconds (0:0:57).
> 
> uhm, non-deterministic

Unfortunately not...

> > The last theory that I have is, that maybe it is simply "too much"
> > for the player in terms of the overall datarate? 
> 
> I doubt it, but I still have to check this possibility.
> If you run mencoder -of mpeg with a low muxrate you can
> see what's the actual needed datarate

mencoder did not work out for me for some reason, I generated a bitrate 
histogram using avidemux2:
http://www.deadlock.dhs.org/jin/libdvdnav/histogram.jpeg

That's probably not exactly what you were asking?

I tried:

mencoder -of mpeg -oac copy -ovc copy -mpegopts muxrate=1800 -o /tmp/out.mpg libdvdnav.mpg

I am not sure if that is correct but the output I get is:
PACKET SIZE: 2048 bytes, deltascr: 245760
videocodec: framecopy (720x576 24bpp fourcc=10000002)
audiocodec: framecopy (format=2001 chans=2 rate=48000 bits=16 B/s=96000 sample-1)
Limiting audio preload to 0.4s.
Increasing audio density to 4.
Writing header...

And then mencoder simply hangs. The output file stays at 2048 bytes and I
need to kill -9 mencoder to get out of this. Using MEncoder 1.0rc2-4.1.2.

> > Btw, this leads me to another question, libdvdnav has a function
> > called dvdnav_audio_language_select(), what exactly is it good for?
> > This does not alter the incoming data anyway, right?
> >
> 
> it only alters the language selection in the DVD VM (its internal
> state-keeping code) not in the application (infact this leads to a lot
> of mess in -at least- mplayer)

I am not using this in my code, just to be sure I commented it out in menus.c
and reripped the mpeg - both versions of the mpeg are the same so I guess that
was not making any difference in this case.

I'll try keeping only one video and one audio stream and playing it with the 
DSM when I get home tonight.

Kind regards,
Jin