It is important to use the same frame rate in the project and the source file to avoid frame dropping in DaVinci Resolve.
A 25 FPS film is the same length in a 24 FPS project and a 25 FPS project in Resolve. To achieve this, Resolve drops every 25th frame. Final Cut X and other software change the film’s length instead and stretch the sound with phase sync. This is the preferred method.
(The same applies to 23.98 FPS films in 24 FPS projects)
If you need to use frame rate conversion in Resolve and want to avoid frame dropping, you can:
-convert the films first in Final Cut X
-change the frame rate on the film and change the length of the sound.
In “Media bin,” right-click the film and choose “Clip Attributes,” Change from 24 to 25. Resolve will now interpret the source file as 24 FPS even if it is 25 FPS. Then you can use this sampling trick to stretch the sound and keep phase sync. The film will be longer but with no frame dropping.