frei0r-mixer-difference gst_segment_to_running_time: assertion 'segment->format == format'

This works:

gst-launch-1.0 -e \
    videotestsrc ! mix. \
    videotestsrc pattern=ball ! mix. \
 frei0r-mixer-difference name=mix ! \
videoconvert ! xvimagesink

This does not:

gst-launch-1.0 -e \
    videotestsrc ! mix. \
    videotestsrc pattern=ball ! mix. \
 frei0r-mixer-difference name=mix ! \
 videoconvert ! x264enc ! mpegtsmux ! filesink location=diff.ts

juser@pdp11:~/temp/gst$ ./gst_diff.sh Setting pipeline to PAUSED ... Pipeline is PREROLLING ... Redistribute latency...

(gst-launch-1.0:2040): GStreamer-CRITICAL **: 18:34:32.390: gst_segment_to_running_time: assertion 'segment->format == format' failed

(gst-launch-1.0:2040): GStreamer-CRITICAL **: 18:34:32.395: gst_segment_to_running_time: assertion 'segment->format == format' failed

juser@pdp11:~/temp/gst$ gst-inspect-1.0 frei0r-mixer-difference Factory Details: Rank none (0) Long-name difference Klass Filter/Editor/Video Description Perform an RGB[A] difference operation between the pixel sources. Author Sebastian Dröge sebastian.droege@collabora.co.uk, Jean-Sebastien Senecal

Plugin Details: Name frei0r Description frei0r plugin library Filename /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstfrei0r.so Version 1.15.90 License LGPL Source module gst-plugins-bad Source release date 2019-04-11 Binary package GStreamer Bad Plugins (Ubuntu) Origin URL https://launchpad.net/distros/ubuntu/+source/gst-plugins-bad1.0