Axis 2420 User Manual page 34

AXIS 2420 User's Manual
Picture frequency for Networking Applications
When used in a TCP/IP networking environment, the AXIS 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:
Resolution
4CIF (704 x 480)
CIF (352 x 240)
* Maximum performance for a single viewing client.
Note:
Using a modern computer will avoid introducing any unnecessary constraints on the image fre-
quency.
NTSC
File size (kb) Max fps*
7 - 150 10
1.4 - 40 30
Choosing Your Application
PAL
Resolution File size (kb)
4CIF (704 x 576) 8.5 - 180
CIF (352 x 288) 1.7 - 50
33
Max fps*
8
25