Wrong m2v duration (GFD/GFM)

[lennu]

When importing m2v (NTSC) file into Gui for Muxman, the duration is not recognized correctly. It says 00:00:00.33, but the actual movie length is 01:36:56.24.
How to i correct it? Because now i can't make chapters.

Btw. I haven't encoded that file myself... (demuxed it from DVD).

GFD/GFM v.0.99.0033

[borax]

...demuxed it from DVD
How (which demultiplexer)?
GfD uses the timecodes in GOP headers to calculate the duration and/or create chapters. If these are wrong, it doesn't work.
Either use another demultiplexer (which already corrects wrong GOP timecodes like projectx), or correct the headers in your m2v file. The later may be done with mpeg2schnitt or cuttermaran (just use the whole m2v file as cut), or maybe with a 'correction' program like restream or videoredo (I have not tried these myself).