Specifications
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By using video encoders, analog video cameras of all types, such as xed, indoor/outdoor, dome,
pan/tilt/zoom, and specialty cameras such as highly sensitive thermal cameras and microscope
cameras can be remotely accessed and controlled over an IP network.
A video encoder also oers other benets such as event management and intelligent video
functionalities, as well as advanced security measures. In addition, it provides scalability and
ease of integration with other security systems.
Figure 5.1b A one-channel, standalone video encoder with audio, I/O (input/output) connectors for controlling
external devices such as sensors and alarms, serial ports (RS-422/485) for controlling PTZ analog cameras and
Ethernet connection with Power over Ethernet support.
5.1.1 Video encoder components and considerations
Axis video encoders oer many of the same functions that are available in network cameras.
Some of the main components of a video encoder include:
> Analog video input for connecting an analog camera using a coaxial cable.
> Processor for running the video encoder’s operating system, networking and security
functionalities, for encoding analog video using various compression formats and for video
analysis. The processor determines the performance of a video encoder, normally measured
in frames per second in the highest resolution. Advanced video encoders can provide full
frame rate (30 frames per second with NTSC-based analog cameras or 25 frames per second
with PAL-based analog cameras) in the highest resolution for every video channel. Axis video
encoders also have auto sensing to automatically recognize if the incoming analog video
signal is an NTSC or PAL standard. For more on NTSC and PAL resolutions, see Chapter 6.
> Memory for storing the rmware (computer program) using Flash, as well as buering of
video sequences (using RAM).
> Ethernet/Power over Ethernet port to connect to an IP network for sending and receiving
data, and for powering the unit and the attached camera if Power over Ethernet is supported.
For more on Power over Ethernet, see Chapter 9.
Analog input
Ethernet (PoE)
Power
RS-485
RS-422
Audio
I/O
CHAPTER 5 - VIDEO ENCODERS