Datavideo HS-1300 Instruction Manual page 55

GOP
GOP pattern with longer GOP length encodes video very efficiently.
Shorter GOP lengths usually work better with video that has quick
movements, but they do not compress the data rate as much. Depending
on your applications, the NVS-31 offers the user 16 GOP sizes ranging
from 1 to 180.
Stream Settings
Stream Type
The NVS-31 offers the user five stream types which are RTSP, RTMP(S),
TS, HLS, and SRT.
Please note that when streaming, the NVS-31 converts video into data,
which are sent across an IP network. High bitrates consume more
bandwidth across the IP network. In a gigabit office LAN, high bitrate may
not be a concern and Speed/Bandwidth is therefore not a limitation in an
NVS-31 application environment.
If your available bandwidth is limited, you should reduce both the
resolution and the bitrate accordingly. A good rule of thumb is for the
bitrate of your stream to use no more than 50% of your available upload
bandwidth capacity on a dedicated line. For example, if the result you get
from a speed test shows that you have 2Mbps of upload speed available,
your combined audio and video bitrate should not exceed 1Mbps.
Stream Type – RTSP
RTSP Port
RTSP Port is 554 by default.
RTSP HTTP Port
RTSP HTTP port is 8000 by default.
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