The video capture API includes enumerated values that specify deinterlacing behavior.

About deinterlacing

Deinterlacing can use a variety of techniques:
Use a motion-adaptive filter. This type of deinterlacing is usually done by the hardware.
Take the lines of each field and double them. This technique retains the original temporal resolution.
Bob 2
Discard one field out of each frame to improve the video quality. The temporal resolution is halved, however.
Combine two consecutive fields together. The temporal resolution is halved: the resulting frame rate is half of the original field rate.
Weave 2
Similar to weave, but the resulting frame rate is the same as the original field rate.
Figure 1. Deinterlacing in BOB mode