This plugin maintains connections to all connected cameras, and buffers a small amount of recent video for instant replays. This instant replay is used by HomeKit Secure Video, as well as speeding up initial live stream load times.
The Rebroadcast Plugin will automatically select the best stream depending on the use. For example, a Unifi Camera has 3 available streams: High, Medium, and Low. Rebroadcast will automatically Prebuffer High for HomeKit Secure Video, and the stream selection will use the following defaults:
High: Local Stream (HomeKit on LAN) and Local Recording Stream (NVR)
Medium: Remote (Medium Resolution) Stream (HomeKit on cellular) and Remote Recording Stream (HomeKit Secure Video)
Low: Low Resolution Stream for Apple Watch, Video Analysis
Most cameras have at least 2 streams available and should be set up as follows:
High: 1080p+ (2000 Kbps) Medium: 720p (500 Kbps) Low (if available): 320p (100 Kbps)
The Key Frame (IDR) Interval should be set to 4 seconds. This setting is usually configured in frames. So if the camera frame rate is 30, the interval would be 120. If the camera frame rate is 15 the interval would be 60. The value can be calculated as IDR Interval = FPS * 4.
Some cameras may not allow configuration of the video codec (h264) or IDR Interval. The camera may also only have a single high bitrate stream which will fail to stream when viewing on low bandwidth remote connections. In this case, Transcoding should be enabled for Remote Stream and Remote Recording Stream to ensure there isn't a bandwidth issue.