in the group by time view, show time elapsed between groups

[kayvonf]

This is worth a try for the view where results are grouped by contiguous time. To make it more obvious how much time has passed between the groups, make a box between the groups that contains the amount of time elapsed between the group to the left and the right.

Note that it's unclear what to do when the group to the left and the right are in different videos. You may want to denote that in a unique way.

This is one of those not-sure-until-I-see-it things.