User`s manual

Attachment B: Bandwidth Estimation

Since the FPS is dependent on the bandwidth of the camera, the relation between the

size of an image file and the bandwidth is always the major concern of the system

construction engineer.

The table below shows the relation between the resolution and size of an MJPEG file

in the NTSC system. Please note that the values in the table are for reference only,

because the size of an image file is closely related to the complexity of the

environment and the actual situation of the place being monitored.

Image Resolution Average range of Data Sizes

176 x 122 (QCIF) 20 – 40k bit

352 x 240 (CIF) 40– 200k bit

640 x 480 (VGA) 180 – 400k bit

704 x 480 (D1) 200 – 530k bit

Ex.: The transmission speed on the Internet is 2fps under 352 x 240, i.e. 40k*2=80k to

200*2=400k per second. It is suggested to apply for a 512K "upload" bandwidth.

Note 1: What the camera needs at the client end is the “upload” bandwidth. However, most

ISPs in Taiwan provide download bandwidth that is wider than the upload

bandwidth. Therefore, symmetrical bandwidth is a good choice for users who need

wider upload bandwidth. Ex. download/upload = 521K/512K

Note 2: 32 kbps to 64kbps are required for transmission of audit signals.