USB cameras 4 distinct USB camera functions GPhoto2 vs Video4Linux2 Still camera that downloads to the PC Video clip camera that downloads to the PC Computer controlled still camera Computer controlled video webcam GPhoto2 vs Video4Linux2 Two entirely different, mutually exclusive ways to talk to a USB camera

GPhoto2 Gphoto2 has 3 out of 4 functions Still camera that downloads to the PC Video clip camera that downloads to the PC PC controlled still camera USB protocol for GPhoto2 is contained in a user-level library called libgphoto2 Basically, gphoto2 is a command line interface for libgphoto2 Libgphoto2 uses libusb to do low level USB work

GPhoto2 command line interface Auto-detection gphoto2 --auto-detect Shows you if you camera is recognized by gphoto2 List the context of camera gphoto2 –get-list-files Get files from you camera gphoto2 –get-all-files

GPhoto2 capture capability Defining Your Camera's Abilities gphoto2 -a Capturing 20 frames with an interval of 60 sec. gphoto2 --capture-image --interval 60 –frames 20 Not all the camera support this feature A list of cameras that support capture http://gphoto.sourceforge.net/doc/remote/

Cannon Capture Capture is a tool for periodic image capturing with digital Canon cameras The consecutive shots are taken without the camera lenses being closed and opened again Supposedly increases camera live http://capture.sourceforge.net/

Libusb API External API for applications to use Core functions usb_init()‏ Initialize libusb usb_find_busses() Finds all USB busses on system usb_find_devices()‏ Find all devices on all USB devices usb_get_busses() Return the list of USB busses found

Libusb API Device operation functions Control transfer functions Bulk transfer functions Interrupt transfer functions No portable functions