Apple Final Cut Pro 7 - Manual (Page 1939)

720p DVCPRO HD Duplicate Frames
720p DVCPRO HD camcorders can record 24 fps footage within a 60 fps signal by
duplicating frames. The duplicate frames are usually flagged within the DVCPRO HD video
signal so applications like Final Cut Pro can automatically remove them. You can also
remove duplicate frames using a frame rate converter (such as the DVCPRO HD Frame
Rate Converter in Final Cut Pro).
The duplicate frame pattern used in 720p24 footage is similar to the standard 3:2 NTSC
telecine pull-down pattern, but there is no interlacing because 720p video is progressively
scanned.
1939 Appendix D Working with 24p Video