4xem WL80 User Manual - Video Codec Parameters
- 41 -
Video Codec Parameters
“Text on video” The text will be displayed in the black bar above the video window
with a timestamp. The timestamp is captured from date and time of the Network
Camera that is maintained by a built-in real-time clock.
“Color” Select either for color or monochrome video display.
"Size" There are five options for three video sizes. “Half” is the quarter size of
“Normal” and “Normal” is the quarter size of “Double”. “Half x 2” has the same video
size as “Normal” but of a lesser quality, while consuming less network bandwidth.
“Normal x 2” has the same size as “Double” but of a lesser quality.
“Video codec type” It can be either MJPEG or MPEG4. In MJPEG mode, the video
frames are independent. In MPEG4 mode, there are I frames and P frames. To decode
a P frame need the information of previous frame. MPEG4 consumes much less
network bandwidth than MJPEG.
There are five dependent parameters provided for video performance adjustment.
"Maximum frame rate" This limits the maximal refresh frame rate, which can be
combined with the "Video quality control" to optimize the bandwidth utilization
and video quality. If the User wants to fix the bandwidth utilization regardless of the
video quality, choose "Fix bit rate" and select the desired bandwidth. MPEG4 video
are composed by I frames and P frames as the following sequence.
IPPPPPIPPPPPIPPPP… “Key frame interval” determines how many repeated P
frames will appear after one I frame. Large “Key frame interval” can reduce the bit
rate, but cause image corrupt longer if there is packet loss while transmission. “Fix
bit rate” option and “Key frame interval” option are only available in “MPEG4”
mode. The video quality may be poor due to the sending of maximal frame rate within
the limited bandwidth when images are moving rapidly. Consequently, to ensure
detailed video quality (quantization rate) regardless of the network, it will utilize
more bandwidth to send the maximal frames when images change drastically.
"Flip" Vertically rotate the video.
"Mirror" Horizontally rotate the video. Check options both if the Network Camera is
installed upside down.
“Improve efficiency in the multi-user environment” Check this option to
improve efficiency in the multi-user environment when running in the low bandwidth
environment. But it will cause each connection slow a few minutes when connection