Re: [libdc] Ignoring bandwidth allocation.

[Tommi I. <to...@mu...>]

Hi,

2008/2/15, Damien Douxchamps <ddo...@is...>:
>
> Hello Tommi,
>
>
> On Wed, 2008-02-13 at 16:28 +0200, Tommi Ilmonen wrote:
> > Hi,
> >
> > I had some trouble running 4 VGA gray-scale VGA cameras cameras at 60
> > fps (FireWire 800), as one cannot allocate that much bandwidth.
> >
> > I then hacked libdc so that it allocates only one half of the actual
> > bandwidth requirements. Now everything works ;-) I have done this also
> > in the past and with some cameras, it works fine, and with others it
> > does not work (at all).
>
>
> I suppose that you don't really stream 4x60fps continuously, otherwise
> the physical bottleneck would remain.


I do ;-)

Are you using software or external
> trigger? Or maybe you're limiting the framerate with the framerate
> feature?


 I have used free-running and software trigger. We'll also use external
trigger, once we have the relevant hardware set up.


> > I know this is not for the faint of heart. Anyhow, would it be
> > possible to have a function that would allow those of us who wish to
> > bypass the spec, to do so?
>
>
> In Linux and OSX you can choose not to allocate any bandwidth (check the
> capture flags). In OSX I have never tried but the code seems to support
> it (line 307-320 of dc1394/macosx/capture.c).


Ah, so I'll RTFM, and see if that has the desired results :-)


-- 
Tommi Ilmonen
Lead Engineer - MultiTouch Oy