For anyone else who has this issue...I was having the same problem and found a workaround.
I have clips shot on a Blackmagic Pocket camera at 50fps that I want to render at 25fps (slow mo). I imported them into Resolve 15.2.2.7 and let the timeline be auto-adjusted to fit the clips. Playback of the clips in the timeline is regular speed. The playback frame rate in the timeline format master settings for the project is set to 50. The Timeline frame rate is locked at 50 (cannot be changed).
- Annotation 2019-02-22 223235.jpg (70.15 KiB) Viewed 13081 times
When I try to render the clip using the "Single Clip" mode the frame rate drop down only allows me to select 50. There are no other options in the drop down.
If I change the project settings Playback frame rate to 25, the clip plays in slow motion in the timeline but still I am only able to export the clip at 50fps. There are no other options available in the drop down:
- Annotation 2019-02-22 220930.jpg (62.09 KiB) Viewed 13081 times
So like Dwaine was saying (I think) I had to create a new project with 25fps as the timeline frame rate. I imported the 50fps footage but didn't let Resolve change the timeline settings. I set the timeline settings to 25fps. Playback in the timeline was then slow motion and I was able to export a 25fps clip. Still no other options were in the frame rate drop down on the render page, but since my timeline was at 25fps the render settings where correct and produced the slow mo clip I needed.