$ ffmpeg -v info -i test.mp4 -vf idet -f null - 2>&1 | grep idet
[Parsed_idet_0 @ 0x80d4358e0] Repeated Fields: Neither:   250 Top:     0 Bottom:     0
[Parsed_idet_0 @ 0x80d4358e0] Single frame detection: TFF:     0 BFF:     0 Progressive:     1 Undetermined:   249
[Parsed_idet_0 @ 0x80d4358e0] Multi frame detection: TFF:     0 BFF:     0 Progressive:   201 Undetermined:    49