Dahua NVRPRO User Manual page 26

The max. system capability that this product series supports is 16-CH standard definition with
transmission rate 2mbps every channel or 4-ch high definition with transmission rate 8mbps.
The delay time for switch-in is under 500ms every channel.
Model System capability
4-ch series Max. switch-in: 4-channel standard definition device with each channel max.
supports 2 Mbps or 2-ch 720P or 1-ch 1080P.
8-ch series Max. switch-in: 8-channel standard definition device with each channel max.
supports 2 Mbps or 4-ch 720P or 2-ch 1080P.
16-ch series Max. switch-in: 16-channel standard definition device with each channel max.
supports 8-channel 720P /4Mbps or 4-ch 1080P.
Definition:
The standard definition device: the devices whose encoding resolution is under D1;
The high definition device: the devices whose encoding resolution is above 720P.
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