427-0089-00-12 Version 100
July 2016
40
3
Advanced Configuration
After making adjustments, scroll down to save your changes through power cycles.
The parameters in the Encoding section will
have a significant impact on the quality and
bandwidth requirements of the video stream. In
general it is recommended that the default
values are used initially, and then individual
parameters can be modified and tested
incrementally to determine if the bandwidth and
quality requirements are met.
For the video streams, the Codec options are
MPEG4 RTSP, H.264 or MJPEG. MPEG4
RTSP requires the least amount of processing,
and MJPEG requires the most.
The Bit Rate parameter is only used when the
Rate Control parameter is set to CBR (Constant
Bit Rate). With the CBR setting, the system attempts to keep the video at or near the target bit rate.
The I-Frame Interval parameter controls the number of P-frames used between I-frames. I-frames
are full frames of video and the P-frames contain the changes that occurred since the last I-frame. A
smaller I-Frame Interval results in higher bandwidth (more full frames sent) and better video quality. A
higher I-Frame Interval number means fewer I-frames are sent and therefore results in lower
bandwidth and possibly lower quality.
The Resolution parameter controls the video resolution and therefore can have a large impact on
bandwidth usage. The larger the size of the frame, the better the resolution and the larger the
network bandwidth required. Table 3-1 provides the corresponding resolution for each setting.
As a rule of thumb, if the video will be viewed on its own and on a reasonably large screen, a large
image size setting may look better. On the other hand, if the video is shown as a tile in a video wall, a
smaller image size may look as good and consume less bandwidth.
Table 3-1: Image Size Settings
Resolution
NTSC
PAL
NATIVE
a
a.
NATIVE and QNATIVE depend on the size of the sensor array. NATIVE resolution is the same
as the size of the sensor array, while QNATIVE is a quarter of the size of the sensor array.
640 x 512
640 x 512
D1
720 x 480
720 x 576
VGA
640 x 480
640 x 480
QVGA
320 x 240
320 x 240
CIF
352 x 240
352 x 288
4CIF
704 x 480
704 x 576
QCIF
176 x 112
176 x 144
QNATIVE
a
320 x 256
320 x 256
