DVR streaming is included in all free trials, and in any plan except for the Basic. You can add DVR when you create a new stream by clicking on "Advanced Settings" and checking the DVR box.
If you want to add DVR to an already existing stream, let us know and we would be happy to configure it for you.
When we turn on this feature for you, that means that people can skip backwards and watch your stream while you are streaming live. Also, when your encoder stops, that live stream will still be available to people in that screen on demand.