Segfaults on vivtc.VDecimate

[polus]

I am just starting to use VapourSynth and I tried to use the vivtc VFM and VDecimate filter on a brief segment from a DVD.
VFM works fine, even though it obviously leaves some duplicate frames. The (subsequent) application of VDecimate, however, reliably produces a segfault when previewing the clip or when viewing in an an external player (mpv) with vspipe.

The error from vsedit in the console is simply:

Floating point exception (core dumped)

mpv gives the same error.

my script is trivially simple:

import vapoursynth as vs
core = vs.get_core()
sourceMovie = core.ffms2.Source(source='/movies/A_VOB_FILE.VOB')
IVTC_clip = core.vivtc.VFM(sourceMovie,1,field=1)
Decimated_clip = core.vivtc.VDecimate(IVTC_clip)
Decimated_clip.set_output()

Is there something I am doing wrong?
I am appending the mediainfo description of the video portion of the file below. I am working on a Linux system with vapoursynth R28-1 and vsedit R5-1

Thanks for the help.

Video
ID                                       : 224 (0xE0)
Format                                   : MPEG Video
Format version                           : Version 2
Format profile                           : Main@Main
Format settings, BVOP                    : Yes
Format settings, Matrix                  : Custom
Format settings, GOP                     : Variable
Format settings, picture structure       : Frame
Duration                                 : 3mn 58s
Bit rate mode                            : Variable
Bit rate                                 : 35.1 Mbps
Maximum bit rate                         : 9 800 Kbps
Width                                    : 720 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 29.970 fps
Standard                                 : NTSC
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 3.391
Time code of first frame                 : 00:59:58:28
Time code source                         : Group of pictures header
Stream size                              : 998 MiB (97%)

[jackoneill]

Originally Posted by polus

Is there something I am doing wrong?

You did nothing wrong. It was just a bug in VDecimate. It's fixed in git now.

[polus]

I am glad to hear I got the basics right! Works like a charm now.