Perform various types of temporal field interlacing.

Frames are counted starting from 1, so the first input frame is considered odd.

This filter accepts a single parameter specifying the mode. Available modes are:

0

Move odd frames into the upper field, even into the lower field, generating a double height frame at half framerate.

1

Only output even frames, odd frames are dropped, generating a frame with unchanged height at half framerate.

2

Only output odd frames, even frames are dropped, generating a frame with unchanged height at half framerate.

3

Expand each frame to full height, but pad alternate lines with black, generating a frame with double height at the same input framerate.

4

Interleave the upper field from odd frames with the lower field from even frames, generating a frame with unchanged height at half framerate.

5

Interleave the lower field from odd frames with the upper field from even frames, generating a frame with unchanged height at half framerate.

Default mode is 0.