On Sat, 2007-09-08 at 19:43 +0200, Andrew Lunn wrote:
> On Sat, Sep 08, 2007 at 06:37:21PM +0200, Roman Haefeli wrote:
> > hi andrew
> >
> > i am not an expert at all in usb-cameras, but i noticed as well, that
> > this camera has been used for astrononimcal purposes, that is why bought
> > it. though i don't know well other usb-cameras, but some dv-camcorders,
> > and i must say, that this spc900nc camera does require only very little
> > light to give quite good results. even with only a weak bulb in the
> > room, the pictures look like they were recorded at daylight (also
> > because of the good withe balancing function).
>
> That is good to hear. Sounds like it should be suitable for my
> purposes.
>
> > the manufacturer also says, that you can achieve framerates up to 90fps.
> > i never got that working with pwc (couldn't try on windows yet). do you
> > know, if the camera is supposed to really deliver that amount of frames?
>
> The FAQ says it cannot do that high a frame rate with VGA resolution
> because it would require too much bandwidth. However the Philips
> website says it is a Hi-Speed USB device, not a Full Speed USB
> device. This could be more Marketing deception from Philips, but a
> Hi-Speed USB device can do 480Mbps, where as a Full Speed device does
> 12Mbps.
i think, this is a marketing deception again. what they actually try to
say, is that the camera is compatible with highspeed usb plugs. don't
know why, but i've got the impression, that there are probably no real
highspeed usb cams around, at least i didn't hear of any. if someone
knows one, that works under linux, that would be great.
> I could understand it not having enough bandwidth with 12Mbps,
> but with 480Mbps USB should not be the limit.
ok, 12Mbps, but why the hell do they claim, you can have 90fps? i'd be
fine with 160x120 @ 90fps, but i don't know how to achieve that.
> Grab a copy of the perl program usbtree at
>
> http://www.linux-usb.org/usbtree
hey, thank you a lot for pointing me to this useful program. here's my
output, while the cam is attached:
/: Bus 04.Port 1: Dev 1, Class=root_hub, Drv=ehci_hcd/6p, 480M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Drv=uhci_hcd/2p, 12M
|_ Port 1: Dev 2, If 0, Prod=, Class=vend., Drv=Philips, 12M
|_ Port 1: Dev 2, If 1, Prod=, Class=audio, Drv=snd-usb-audio, 12M
|_ Port 1: Dev 2, If 2, Prod=, Class=audio, Drv=snd-usb-audio, 12M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Drv=uhci_hcd/2p, 12M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Drv=uhci_hcd/2p, 12M
|_ Port 1: Dev 2, If 0, Prod=USB-PS/2 Optical Mouse, Class=HID,
Drv=usbhid, 1.5M
the clear proof, that it only uses full speed. these bastards.....
roman
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