[GEM-dev] pwc problem / help appreciated

[Roman Haefeli]

On Thu, 2007-09-20 at 01:36 +0200, cyrille henry wrote:
> hello,
> 
> 
> Roman Haefeli a écrit :
> > hi cyrille
> > 
> > thanks a lot for your effort. the object does instantiate without any
> > troubles. first, when i banged it, i got:
> > 
> > VIDIOCPWCRUSER: Invalid argument
> > 
> > then i realized, that the video device must be hardcoded somewhere and
> > is probably hardcoded to /dev/video0. actually my cam is running
> > on /dev/video1. so i changed it in the code and compiled the object
> > myself. 
> this could easilly be fixed if a clean object was needed.
> 
> > when banging, i get now:
> > 
> > VIDIOCPWCRUSER: Bad file descriptor
> > 
> > unfortunately, i don't have a clue at all, what this means. 
> me neither.
> 
> did you try it before and after creation ot the pix_video object?
> did you try with gem rendering on and off?

ok, i think i sorted it out. when writing the last mail, i only tried
sending the bang, _after_ rendering was started. it seems like i got the
error, because the cam was already 'occupied' by gem. 

now i tried to do it _before_ i start rendering. this seems to work,
since i get no error and the led of the cam is lighting up. BUT: the cam
seems to stay occupied by [setpwc] until i close pd, which means i
cannot access it with [pix_video] anymore, after i banged [setpwc].

i think, it canNOT be solved by adding a 'close' method to [setpwc],
because then i'd have the problem again, that the cam is 'forgetting'
it's settings again. 



> > the idea of having such an object is a genius idea, since it makes the
> > cam usuable for all video externals at the same time without having to
> > change the code of the externals. actually, i didn't know, that it could
> > be done outside of gem, but it seems like that it could.

no, it seems like the 'VIDIOCPWCRUSER' needs to be included in
gem/pix_video/<or whatever code manages the access to the video devices>
the command should be executed, whenever rendering starts in gem (which
is the same as 'whenever the video device is opened').

your [setpwc] and [pix_film] seem to look like two different
applications from the pwc-drivers perspective.


> in fact, i realize that this object would do exactly the same than starting setpwc on a terminal afer pd is starded. 
> did you try using setpwc afer starting pd?

it obviously does the exact same thing, whith the drawbacks.
the problem here is the same: the programm setpwc cannot access the
devices, when pd/gem is using it. same problem as with [setpwc].

would it be difficult to port the exact same thing, as you did in
[setpwc], to gem/pix_videoNEW.cpp, so that it would not use a bang to
trigger 'VIDIOCPWCRUSER', but the start_rendering command?

roman


		
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