If you observe the output below, you will see that the progressive, repeated fields , single frame and multiple frame have values in them. This should give you an idea that it’s an interlaced video. Also most interlaced videos will have an ‘i’ in them. e.g. 1080i

/Users/darshan/Downloads/ffmpeg -filter:v idet     -frames:v 100     -an     -f rawvideo -y /dev/null     -i /Users/darshan/Dropbox/Public/1080i/interlaced/Mug\ Drop_Interlaced_4ss.mp4 

video:303750kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%
 [Parsed_idet_0 @ 0x7facaf200000] Repeated Fields: Neither:    63 Top:    20 Bottom:    18
 [Parsed_idet_0 @ 0x7facaf200000] Single frame detection: TFF:    81 BFF:     0 Progressive:    20 Undetermined:     0
 [Parsed_idet_0 @ 0x7facaf200000] Multi frame detection: TFF:   101 BFF:     0 Progressive:     0 Undetermined:     0