How to capture interleaved frame fro QUAD HDMI Recorder card

Untitled 01 1.jpg (310.95 KiB) Viewed 982 times

The up image is the captured interleaved frame (HD1080i50,upper field first)from QUAD HDMI Recorder card,it seems the interleaved frame is stored as two seperated field images,so I try to copy the upper field image to line1,line3,line5,...,and copy lower field image to line2,line4,line6,...,to combine it as field-interleaved image,but the combined image is wrong,it looks like field is not in the correct line; I also try to copy upper field to line2,line4,line6,lower field to line1,line3,line5,but I failed too; So how to combine the field-seperated image to field-interleaved image?