Choosing Your Application AXIS 2420 User’s Manual

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Picture frequency for Networking Applications
When used in a TCP/IP networking environment, the AX IS 2420 delivers up to 30/25
(NTSC/PAL) images/second. The perceived frame rate in your browser is typically limited
by:
the number of clients accessing the images
your computer and browser
the chosen image resolution and compression
the lighting conditions at the point of installation
available network bandwidth
the complexity of detail and color variation within the image
Note: The AXIS 2420 is available in NTSC and PAL variants to accommodate the different power supply
frequencies in the USA and Europe.

Image Compression Ratios

Although the file size of a JPEG-compressed image depends upon the actual content of the
image, images containing great detail generally generate larger files. Image quality is
largely controlled through the level of compression; where high compression yields small
files, and low compression maintains higher image quality at the expense of larger files.
The table below is derived from real-life tests, and defines the average file sizes for each
supported image resolution:
* Maximum performance for a single viewing client.
Note: Using a modern computer will avoid introducing any unnecessary constraints on the image fre-
quency.
NTSC PAL
Resolution File size (kb) Max fps* Resolution File size (kb) Max fps*
4CIF (704 x 480) 7 - 150 10 4CIF (704 x 576) 8.5 - 180 8
CIF (352 x 240) 1.4 - 40 30 CIF (352 x 288) 1.7 - 50 25