V4L2_FIELD_ANY
V4L2_FIELD_NONE
V4L2_FIELD_TOP
V4L2_FIELD_BOTTOM
V4L2_FIELD_INTERLACED
V4L2_FIELD_SEQ_TB
V4L2_FIELD_SEQ_BT
V4L2_FIELD_ALTERNATE
V4L2_FIELD_INTERLACED_TB
V4L2_FIELD_INTERLACED_BT