Bandwitth Needed for 640by480 30fps video capture froma we..

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Bandwitth Needed for 640by480 30fps video capture froma webcam is ???


I just bought a Logitech Webcam 4000 Pro. And having a few probs
getting good quality videocaptures with it.

In Automode they are great but when you turn off the lowlight filter
the video becomes grainly. Not sure why it needs a low light filter
turned on to give a good picture as i do have the lights turned on :)

Also with the low light filter is on it is in Automode and the
framerat eis 1/10 10 fps. But if i up the shutter speed to 30 fps the
brightness gos down and i have to up the gamma and brightness to
getthe same brightness.

The problem with that is it makes the video grainyl and white dots all
over the screen. The picure is not horrible. But you loose clarity
and the vividness when it son auto mode :( its just not crisp video
liek when in automode.

Iam think maybe 12mbs speed is just not enough and you realyneed a
REAL usb 2 camera to get the proper captures.


Thanks for any help.
 
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Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

"On Holidays" <abbyrow.com.uk> wrote in message news:iedk919knrju7pr6d440fd013ue47t6gr7@4ax.com...
>
>
> Bandwitth Needed for 640by480 30fps video capture froma webcam is ???
>
>
> I just bought a Logitech Webcam 4000 Pro. And having a few probs
> getting good quality videocaptures with it.
>
> In Automode they are great but when you turn off the lowlight filter
> the video becomes grainly. Not sure why it needs a low light filter
> turned on to give a good picture as i do have the lights turned on :)

"Low" is a relative term. You need very bright* light for good quality pictures.

* another relative term ;o)

> Also with the low light filter is on it is in Automode and the
> framerat eis 1/10 10 fps. But if i up the shutter speed to 30 fps the
> brightness gos down and i have to up the gamma and brightness to
> getthe same brightness.

That's because, at 30fps, you only get one third of the exposure you get at 10fps.

> The problem with that is it makes the video grainyl and white dots all
> over the screen. The picure is not horrible. But you loose clarity
> and the vividness when it son auto mode :( its just not crisp video
> liek when in automode.

Yep. Essentially, the image is under exposed, and it has to be "forced" to get acceptable brightness. This introduces "noise" into
the image (grain + white dots).

> Iam think maybe 12mbs speed is just not enough and you realyneed a
> REAL usb 2 camera to get the proper captures.

Try a bigger lightbulb, or a spotlight - it should help.

cheers,

Brian