61General performance considerationsBandwidthAs there are many factors that affect bandwidth, it is very difficult to predict the requiredamounts. The settings that affect bandwidth are:• image resolution• image compression• frame rate• MPEG-4 GOV settings• bit rate control settingsThere are also factors in the monitored scene that will affect the bandwidth. These are:• amount of motion• image complexity• lighting conditionsFor MPEG-4, if there is only limited bandwidth available, and if this is more importantthan the image quality, using a constant bit rate (CBR) is recommended. Use a variable bitrate (VBR) if the image quality needs to be maintained at a higher level. If supported on thenetwork, consider also using MPEG-4 multicasting, as the bandwidth consumption will bemuch lower.