User Guide

427-0075-01-12 Revision 140 October 2019 49
This document does not contain any export-controlled information.
Basic Operation and Configuration
The time-to-live field controls the ability of IP packets to traverse network boundaries. A value of 1
restricts the stream to the same subnet. Greater values allow increasing access between networks.
The video streaming is done using a protocol generally referred to as Real-time Transport Protocol
(RTP), but there are actually many protocols involved, including Real-Time Transport Control
Protocol (RTCP) and Real Time Streaming Protocol (RTSP). In the background, a “negotiation”
takes place to establish a session between the client (such as FLIR Latitude, a third party VMS, or
video player) and the camera. The ports which form a session are negotiated using a protocol such
as RTSP. A client typically requests a video stream using its preferred settings, and the camera can
respond with its preferred settings. As a result, many of the details are established dynamically,
which may run contrary to network security requirements.
The parameters in the Stream Settings section will have a
significant impact on the quality and bandwidth requirements
of the video stream. In general it is recommended that the
default values be used initially, and then individual
parameters can be modified and tested incrementally to
determine if the bandwidth and quality requirements are
met.
For video streams, the Codec options are H.264 and
MJPEG.
The Frame Rate parameter controls the number of frames
per second in the video stream.
The I-Frame Interval parameter controls the number of P-frames used between I-frames. I-frames
are full frames of video and the P-frames contain the changes that occurred since the last I-frame. A
smaller I-Frame Interval results in higher bandwidth (more full frames sent) and better video quality.
A higher I-Frame Interval number means fewer I-frames are sent and therefore results in lower
bandwidth and possibly lower quality.
When the Rate Control Type parameter is set to VBR (Variable Bit Rate), the Bit Rate parameter is
used as an upper limit bit rate and the system keeps the stream at or under the target bit rate. When
the Rate Control Type parameter is set to CBR (Constant Bit Rate), the Bit Rate parameter is used
as a target bit rate. The system attempts to keep the bit rate of the video at or near the target.