[linux-dvb] Re: VDR 0.80pre8

[Jan Panteltje <root@panteltje.demon.nl>]

On Wed, 30 May 2001, Klaus Schmidinger wrote:

> Jan Panteltje wrote:
> > 
> > On Mon, 28 May 2001, Ralph Metzler wrote:
> > 
> > >  > plaing back with 0.0.4 .
> > >
> > > Just for the audio underflow problem such re-arranging could be
> > > enough. It is probably a lot less overhead than a complete re-muxing.
> > >
> > >
> > >  > It is professional quality really, after more the 15 tapes produced that
> > >  > way I have not had ONE complaint about audio / video sync.
> > >  > And there are NO picture jitters either.
> > >  > Maybe you need to step back and ask: What was so good about 0.0.4?
> > >
> > > It had less strict syncing which I am using now too. There should be
> > > no jitters in the current driver's playback.
> > > Also, 0.4.0 did not always start in sync. This is actually better in
> > True, I solved tha tby doing a seek somewhere a bit into the file,
> > there is a point where the sync is OK, but starting on say a frame (B or
> > whatever) does not seem to do it.
> > So I just added a comman line parameter to my playback / subtitle program
> > and try a couple of values.
> 
> Does this mean that whether or not buffer problems occur depends on where 
> you start replaying a file? This might explain why, in case the sound is
> lost during replay, it returns if I restart replay, and even stays on over
> and beyond the point where it originally went off.
> 
> Klaus
It is possible, but I can only speak for recordings in av_pes I made
with driver 0.7.1 and played back with driver 0.04.
Since it works so well, I will stick with that, better then perfect is not
possible IMO.

This brings me to my opinion on the whole 'big picture'.
IMO this ost stuff has brought a lot of problems.
Two things a software writer (like me) does not like:
1 Change the API so I have to rewrite everything.
2 New version need newer kernels.

On my system upgrading kernel is just not simply possible, as then hundreds
of other programs need recompiling, been there done that.

So if it was me:
For Unix beauty sake use /dev/video and all operations on that.
But I may be wrong about that.
And write kernel independend.
If your argument is: kernel changes are no problem, because VDR will run
just all by itself on a box, then you could just as wel use no modules,
but write a program that directly access the hardware as root, thus
eliminating going via the kernel altogether.
I am aware of the Nokia - Convergence decision of ..ost, but looking at 
it from the point of a user, who wants to use the card to record and
playback DTV, then all I would want would be it to work really.
And without upgrading kernel, or any other experimentation.
Something is wrong in the current approach.
I faced the same problem with my webcam software
( http://www.panteltje.demon.nl/mcam ) and in that case decided to avoid
v4l and kernel modules and simply run as root and write to the ports
directly. Result it runs on all versions of Linux.

I am not sure if there is a theoratical advantage in using a module
over just an application at all.
Interesting was an interview I did read with Linus, where he confirms
tha tthe biggest force against new kernels is that nobody really needs the
new features, the current kernels work great.
FYI there was a few weeks a ago a nice interview with Linus on ZDF I think.,
where he explaines he has a tivo at home.
hey, maybe someone should tell him about VDR :-)
 

Regards
Jan






> -- 
> _______________________________________________________________
> 
> Klaus Schmidinger                       Phone: +49-8635-6989-10
> CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
> Hofmark 2                               Email:   kls@cadsoft.de
> D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
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