I am working with neo 3D (latest betaversion) and I recognized that the playback within FirstLight is stuttering in my muxed stereofile. I am working in the PAL area and when I take a look to the metadata ->cineform, I see the timecode base is 30, but I need 25. How can I change this?

If it is an AVI I use AVIFrate.exe (free download form many places) to set a new playback speed in the file. Also I often set the playback resolution in FirstLight to half for 3D modes which can take a lot of CPU.

Do I understand it right? The internal framerate if neo is always 30? I do not need a framerate conversion, we shoot in 25 and I will still stay within 25. But if neo translate this internal to 30 frames what happens to my whole worklflow. Do I stay native in 25 (for my project)?

No, frame rate matches the source. If you see otherwise, please contact support.