> >> 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
You're right. My UVC parsing code in usb-utils has a small bug which reported invalid values for bStillCaptureMethod. > > 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. ;-) I'll try to work on still image capture in the near future. I'm quite busy with another project right now, so there might be some delay. Still image capture method 2 requires the driver to suspend video streaming, so I might have to change some code deep in the driver. Hopefully I'll find a not too intrusive way. Cheers, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
