What are mainstream and substream?
The recorder will send out two video streams when you are viewing on your computer, smartphones, tablets, etc.
One is the mainstream - this uses 4-5 Mbps for 1080p 30FPS for each camera and around 6Mbps for a 4MP camera. The mainstream is the exact quality the NVR always records at. Due to the high quality and high bitrates of mainstream some computer’s CPU will struggle to play all available cameras at mainstream and most internet connections upload speed will be unable to keep up.
Substream is a secondary stream coming from the recorder or cameras. This is customizable but at most uses about 512Kbps and is standard definition quality. This is great for viewing on some computers and most internet connections.
Note: Even when viewing substream, the system will still record on the full, main stream quality.