Digital video recorder in video monitoring system and network connection control method thereof

The invention relates to the field of video monitoring, and discloses a digital video recorder in a video monitoring system and a network connection control method thereof. The method comprises the following steps: when the residual bandwidth is not sufficient to support newly added code streams, lowering the code stream characteristics step by step to adapt to the overall bandwidth, recoding all the code streams by using the adjusted code stream characteristics and transmitting the code streams, so that the digital video recorder can support more clients by using limited bandwidth while viewing the monitoring video; and when the number of connected clients decreases, under the limit of rated overall bandwidth, trying to rising the code stream characteristics, thereby realizing code stream adjustment in a self-adapting mode.