Live stream and recorded stream DVR style buffer/15 second jump back and forward

When viewing playback or live feed, you should be able to jump back 15 or 30 seconds at a time to replay an event.

For livestream, it should save the latest 30 seconds to the local cache in addition to writing to the SD card.

For playback from the SD card, it should allow quick jump back or forward in time like you can on a DVR.

This would make playback much easier for viewing events.