frame flickering problems, and question about 23.9fps??

[h8sh8]

G'day, I have 2 avi files which I've converted from 23.9 FPS to 25FPS. They play fine on PC, but in the 2 dvd players I've tested, they both jump or flicker. They don't seem to skip frames - it's more like it quickly flashes up a frame from a couple of frames previous, and then continues. One has AC3 audio, and the other some other audio which I didn't need to demux. There's no audio sync problems either. I used TMPGEnc 3.0 Xpress for conversion. They both had the pixel dimensions closer to 16:9 so I put input and output as that. I'm wondering if it's a problem with choosing 16:9 or something to do with bitrate - they're the 2 main things I didn't know what I was doing with. Other than the quick flicker every 2-3 seconds, everything else seems perfect.
Any help appreciated - cheers.
Let me know if more info is needed.
I used VSO DivxToDVD, to convert 23.9 to 25fps, and the flickering doesn't happen, but I get really bad pixelation every so often using VSO - usually on movement but only occasionally, though it happens on everything I've converted so far (about 6-7 avi) with VSO.

Also, while I'm asking, does it matter if when converting it is left as 23.9 NTSC - all my tvs and dvdplayers play both PAL and NTSC dvds no problems, but these 2 ntsc frame rates are confusing me - will 23.9 be compatible with all ntsc supporting dvdplayers/tvs - I thought ntsc dvds were around 29fps??

cheers.

[guns1inger]

When you convert 23.976fps NTSC for DVD you apply a pulldown flag that tells the playback device to manufacture the frames required to make playback 29.976 fps. VSO does this. DGPulldown also does this to mpegs if you encode standalone with soemthing like tmpgenc.

I don't bother doing doing format conversions because all my kit is multi-system. I encode all NTSC source at 23.976, then apply pulldown before authoring as NTSC.

[h8sh8]

Thanks heaps for the help guns1inger, much appreciated mate.