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Grabbing a single field

With interlaced scanning cameras, 2 fields are grabbed by default; therefore one call to MdigGrab() will grab both the odd and even fields. You can change the number of fields to 1 and have MIL treat each field as one frame using MdigControl() with M_GRAB_FIELD_NUM, grabbing every second row and storing them in sequential rows. Therefore, the grab time is reduced by half. This control type can only be set to 1 or 2, and should only be used for interlaced video. When set to 1, each field is treated like a frame and the following digitizer events occur relative to the grabbed field: M_GRAB_FRAME_START, M_GRAB_END, and M_GRAB_FRAME_END. To achieve 60 fps in NTSC or 50 fps in PAL, the control type M_GRAB_START_MODE must be set to M_FIELD_START.