## Recording at Night - variable bit-rate codecs use periodic keyframes followed by deltas to compress the stream, assumption being that most frames change little from frame to frame - variable bit-rate video codecs require more bandwidth in low light or dark. - In low light, camera has to increase gain on the sensor, which increases random noise in each frame. This increases the differences from frame to frame. Low-light, high-noise doesn't compress well under VBR encoding. > When a camera sensor has lower light to work with it has to increase gain to compensate, similar to increasing ISO on a DSLR. This increase in gain also introduces image noise which is completely random from frame to frame and very difficult for the camera or any video encoder to efficiently compress. While noise reduction algorithms are applied to reduce the noise (you'll find a slider for this in the image quality settings), it is impossible to completely remove all noise without risking also removing detail from the recording - thus the encoder requires higher bitrate to retain a suitable image quality. [source](https://community.ui.com/questions/High-overnight-bandwidth-utilization-for-Unifi-Protect/b4089116-9a01-42f4-b1ac-abc1680fd865#answer/f905871b-a747-4381-be46-13538549baeb)