AVISynth plugin for converting variable frame rate clips to constant frame rates. To use the plugin you also need to have the FFmpegSource2 plugin.
LoadPlugin("..\build\Release\VfrToCfr.dll")
# Dump the time codes from the VFR clip
ffvideosource("test.mp4",timecodes="timecodes.txt")
# Use the time codes file to figure out when the frames should be
# displayed in the resulting NTSC CFR clip.
vfrtocfr(timecodes="timecodes.txt", fpsnum=30000, fpsden=1001)
For the VapourSynth equivalent, take a look at test/test.vpy
Compile the plugin from the Visual Studio GUI. A project and solution file can be found in the build directory.
The project code and binaries are made available under LGPL v2 license.