Not possible, I'm afraid.

Cheers
Adrian Life is really simple, but we insist on making it complicated. (see below)
Confucius
AMD Phenom IIX6 1055T, win10, 5 internal drives, 7 usb drives, struggling power supply.

You can choose 25 frames, which is one half of 50 frames. Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

Really???? every NLE I've played with lets you sync the time line to the fps you want for your project.

The downside is that any frame accurate requirment that is not 25 or 30fps gets hard. eg - I'm only going to be able to see each second frame of my 1080/50p video on the timeline. FYI - I noticed this issue when I was trying to make a 50fps test pattern from repeating in order 50 unique still images each set to a duration of 1 frame.

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Also - Just had a play adding a 24fps video to the "PAL" timeline and sure enought it adds a second Frame 0 (eg Frame 0 and 1 are the same) to get a 24fps to appear nicely on a 25fps timeline...very poor approach IMHO.

PD 64 Bit-Win10 64 Bit-32GB RAM-80TB HDD
Sony FX6 - 500Mbps 4k/50p AVC-I HLG
Canon XF400 - 150Mbps 4k/50p AVC
GoPro Hero6 Black
Pana HS700-28Mbps 1080/50p AVC (High@L4.2)
Canon HV20-HDV 25Mbps 16:9 1440x1080/25p MPEG

FYI - The PAL / NTSC selection for the Timeline is stored in the Registry (HKEY_CURRENT_USER --> Software --> Cyberlink --> PowerDirector --> 9.0) in "DisplayCurFrame" where:
00 00 00 00 = PAL
01 00 00 00 = NTSC

....unfortunatly I could find no other value to do anything (all resets it back to 00 00 00 00 = PAL) - so no reg hack here to support other values on the Timeline.... PD 64 Bit-Win10 64 Bit-32GB RAM-80TB HDD
Sony FX6 - 500Mbps 4k/50p AVC-I HLG
Canon XF400 - 150Mbps 4k/50p AVC
GoPro Hero6 Black
Pana HS700-28Mbps 1080/50p AVC (High@L4.2)
Canon HV20-HDV 25Mbps 16:9 1440x1080/25p MPEG