User`s manual

VPort 251 User’s Manual System Configuration
Resolution
The VPort 251 supports 5 different resolutions: Full D1, 4CIF, VGA, CIF, and QVGA.
Setting Description Default
Select the image size
5 image resolutions (size) are provided.
The administrator can choose each option
with NTSC or PAL modulation.
720
x 480 in NTSC or
720
x 576 in PAL
Resolution NTSC PAL
Full D1
720
x 480 720 x 576
4CIF
704
x 480 704 x 576
VGA
640
x 480 640 x 576
CIF
352
x 240 352 x 288
QVGA
320
x 240 320 x 288
Frame Rate (Frame per second)
Setting Description Default
Maximum frame rate
The maximum frame rate is different to
accommodate different modulations of
video input. Administrators can also set
up the maximum frame rate to optimize
the bandwidth’s occupation.
30 for NTSC
25 for PAL
Key frame interval
(Only for MPEG4)
Administrators can set up the key frame
interval to determine the video quality.
15
NOTE
Frame rate (frames per second) is determined by the resolution, image data size (bit rate), and
transmission traffic status. The Administrator and users can check the frame rate status in the
FPS Status on VPort’s web homepage.
NOTE
A large “Key frame interval” can reduce the bit rate, but will cause the image to be corrupted
longer if there is packet loss during transmission.
4-27