It makes no sense for a decoder to output a BYTES segment, and
many elements one would plug downstream of a video decoder assume
the segments they receive are in TIME format, for example this fixes:
gst-validate-1.0 filesrc location=opacity01.svg ! gdkpixbufdec ! \
videobalance ! videoconvert ! fakesink
In that case, videobalance was emitting an assertion when trying to
call gst_object_sync_values()