different fps with QTGMC

[taigi]

Using QTGMC with ASynth+, VDub2.
Original is 25fps.
Checking what fps result will be.
Instead of 50fps there are 49,425fps (attached).
Maybe that's just me, but it looks sometimes I saw 49,427fps at the same place.
Encoding.
Result is still 49,425fps.
Should I force to 50fps?
Thanks.

[jagabo]

In all likelihood your AviSynth source filter is delivering the wrong frame rate. This typically happens with video that has been trimmed from a longer video and has a few unused b-frames at the start and/or end.

[taigi]

@jagabo, so I just need to force it to 50fps?

[jagabo]

Make sure your source isn't variable frame rate. If it is, force it to constant frame rate with something like LWlibavVideoSource("filename.ext", fpsNum=50000, fpsDen=1000).

If the issue is leading/trailing b-frames you can just assume the source is 25 fps, AssumeFPS(25), or assume the output of QTGMC is 50 fps, AssumeFPS(50).

[taigi]

Can I just click "Change frame rate to" and type "50" in that VDub2 dialog screenshot of which I attached?

[jagabo]

That should work.