The bitrate during a videoconference can be very dynamic, for example being very low if the camera is pointing to a wall and increasing inmediatelly if a person starts moving. This behaviour can be a problem with networks that take some time to adapt changes in traffic (specially mobile networks) and can be alleviated by keeping a constant bitrate by sending fake packets when there is no enough actual data to maintain that bitrate. This is very easy to do by using RTP padding with random data but can be done even better by adding redundancy or retransmissions so that those packets can convey useful information in case of packet loss.
翻譯：
電視會議期間的比特率可能非常動態，例如，如果攝像機指向牆壁，則比特率很低；如果有人開始移動，則比特率會立即增加。 這種行爲可能是需要花費一些時間來適應流量變化的網絡（特別是移動網絡）的問題，並且可以通過在沒有足夠的實際數據維持該比特率的情況下發送僞造的數據包來保持恆定的比特率來緩解。 通過對隨機數據使用RTP填充非常容易做到這一點，但是通過添加冗餘或重傳甚至可以做得更好，以便在丟包的情況下這些包可以傳達有用的信息。
原文：http://www.rtcbits.com/2013/12/pacing-pading-and-automuter.html