The HDR-FOX T2 and NTSC files


Hi all - I've converted a few favourite films (Laurel & Hardy), ripped from DVD and saved as .TS files onto a shared drive the T2 has access to using the custom firmware, and these work as well as do those programmes recorded by the T2, with fast forward and bookmarking.
However, I thought I'd try the same with a few favourite episodes of Diana Rigg era Avengers, from discs I bought from the US many years ago.
The files are quite juddery, which I would assume is due to playing back NTSC files on a PAL box. I can, though, use the T2 as a server and then use my smart TV as client and they play back perfectly, but this seems a bit of a roundabout way and I don't get bookmarking etc. going this route.
Is there anything I could set/unset within the T2 that would play back these files smoothly or is this impossible?
Thanks in advance for any help.