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 could understand it not having enough bandwidth with 12Mbps,
but with 480Mbps USB should not be the limit.
Grab a copy of the perl program usbtree at
http://www.linux-usb.org/usbtree
When you run it you should get something like:
/: Bus 04.Port 1: Dev 1, Class=root_hub, Drv=ohci_hcd/2p, 12M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Drv=ohci_hcd/2p, 12M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Drv=ohci_hcd/2p, 12M
|_ Port 1: Dev 2, If 0, Prod=, Class=HID, Drv=usbhid, 1.5M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Drv=ehci_hcd/6p, 480M
|_ Port 3: Dev 3, If 0, Prod=External HDD, Class=stor., Drv=usb-storage,
480M
Port 1 is a USB mouse, running at 1.5Mbps. It is an old USB 1.1 device.
Port 3 is a hard disk, Hi-Speed device, running at 480Mbps.
What does you webcam show? 12 or 480?
Andrew
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