FLIR PT-602CZ Installation Manual page 38

2 Basic Operation and Configuration
There are some challenges with streaming video over an IP network, when compared to other
traditional IP applications which are less time-critical, such as email and web browsing. In particular,
there are requirements which must be fulfilled to ensure satisfactory video quality in professional
security environments. There are many parameters and factors related to network infrastructure,
protocols, codecs, and so on that can affect the quality and bit rate of a video stream when it is
established between the camera and a client.
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.
In some networks, the RTP/RTSP traffic is carried (tunneled) over Hypertext Transfer Protocol (HTTP)
as that may allow the traffic to cross network boundaries and firewalls. While this method involves
more overhead due to encapsulation, it may be necessary for clients to access the video streams
when HTTP proxies are used.
RTSP is originated and received on even port numbers and the associated RTCP communication uses
the next higher odd port number; the default RTSP Port is 554.
The parameters in the 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
are used initially, and then individual parameters can be
modified and tested incrementally to determine if the
bandwidth and quality requirements are met.
For the video streams, the Codec Type options are MPEG4,
H.264 or MJPEG. MPEG4 requires the least amount of
processing and MJPEG requires the most.
The Bit Rate parameter is used with the CBR (Constant Bit
Rate) setting to attempt to keep the resulting bit rate of the
video at or near the target bit rate.
When the Rate Control parameter is set to CVBR (Constrained
Variable Bit Rate), the Bit Rate parameter is used as an upper
limit bit rate and the Quality setting further adjusts the amount
of video data in the stream; the system keeps the stream at or
under the target bit rate.
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.
427-0038-00-12 Version 110 March 2018 38