REMB stands for Receiver Estimated Maximum Bitrate. This is an RTCP message that uses bandwidth control to prevent network congestion.

The RTCP message includes a field for transmitting the total estimated available transmission rate on the way to the receiving side of the RTP session (in the mantissa + exponent format). Even if it is defined as the total available bitrate, the sender usually uses it to set the maximum bitrate for video encoding.

In addition to using REMB for notifications of available network bandwidth, it is also used by media servers to limit data transfer rates.

To give a better estimate, REMB is usually used in conjunction with the abs-send-time header extension, since providing accurate timing information is crucial for the accuracy of calculating the REMB value.