On Wed, 14 Feb 2007 08:18:10 -0800, Thad Phetteplace <[EMAIL PROTECTED]>
wrote:
> On 2/14/07, Laurent Pinchart <[EMAIL PROTECTED]> wrote:
>>
>> The good news is the QC notebook pro can capture video at 1.3 megapixel
>> as well :-) All UVC webcams I am aware of implement still image capture
>> method 1, which means they don't implement still image capture at all
>> (method 1
>> emulates still image capture in software).
Laurent is right for the first part, all our Logitech QuickCam UVC cameras
(except the QuickCam Pro 5000, which has a VGA sensor) can indeed stream
at 1.3 MP. It's done without interpolation.
However, they have method 2 still image capture support. Here's the
corresponding section from the UVC descriptor: (This happens to be from a
Pro 5000, but the others should be the same.)
===>Video Class-Specific VS Video Input Header Descriptor<===
bLength: 0x10
bDescriptorType: 0x24
bDescriptorSubtype: 0x01
bNumFormats: 0x03
wTotalLength: 0x0270 -> Validated
bEndpointAddress: 0x81 -> Direction: IN - EndpointID: 1
bmInfo: 0x00 -> Dynamic Format Change not
Supported
bTerminalLink: 0x05
bStillCaptureMethod: 0x02 -> Still Capture Method 2
bTriggerSupport: 0x01 -> Hardware Triggering Support
bTriggerUsage: 0x00 -> Host will initiate still image
capture
> I seem to remember reading that the QC notebook pro interpolates
> frames when streaming at resolutions greater than 640x480, but does
> a non-interpolated still capture. This is easy enough to test. I can do
> some capturing and compare image quality. I also have a log of usb
> traffic. I can look at the transfer frames and see if the snap sends
> more data.
>
> Not sure if I'll get to that today... I'm currently neck deep in an
> embedded linux driver project. Then again, if my new variable power
> supply doesn't show up soon, I'll be spinning my tires and have plenty
> of free time... :(
I don't want to be unsupportive, but in the name of the Linux webcam
community, let's hope for some shipping delay on your power supply. ;-)
Cheers,
Martin
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