How do Pre-Roll and Post-Roll work together in OnGuard?

Question

How does Pre- and Post-Roll work together in OnGuard?

Pre-Roll: The pre-roll is the number of seconds automatically subtracted from the start time of alarms/events, generated by a camera, to ensure that the video associated with the event includes footage prior to the actual event. For example, if a criminal disables a camera before executing a crime, the pre-roll greatly increases the odds that a video event includes the footage of the criminal disabling the camera.
Post-Roll: The post-roll is the number of seconds automatically added to the end time of alarms/events, generated by a camera, to ensure that video with the event includes footage of the scene after the actual event.

The Playback Post-Roll cannot be effective on the latest event when:

The value entered for Event Post-Roll is less than the value entered for Playback Post-Roll
The selected channel has Event Recording enabled and Continuous Recording disabled

This is expected behavior and is by design. For more information, refer to the following details:

In Event-only recording mode, the End time of the channel on the recorder will be +<:event post-roll>.
For example, assume Event Pre-roll and Post-roll are set to 10 secs, and Playback Pre-roll and Post-roll are set to 20 secs. In this case, if last event occurs at 1:00:30, the channel has recorded video unti1:00:40 (as Event-post roll of 10 secs).
When user tries to launch video on this last Event – it tries to play video from “ - ” till “<:event time> + ” which in this case is from 1:00:10 till 1:00:50.
Since recorded video is available only till 1:00:40 the launch video plays from 1:00:10 till 1:00:40 only.

OnGuard (All versions)