Digital Watchdog MEGApix DWC-MV74Wi28, Руководство пользователя, Страница: 27 / 84

Video Configuration
Setup - Video & Audio Setup
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GOP(Group of Pictures) Size
Set up the number of frames (P-frame) which contain only
changed information based on basic frame (I-frame).
Regarding videos with lots of movement, if you set GOP size
bigger, only the number of P-frames is bigger. As a result,
video resolution will be low but ‘File size’ and ‘Bit-rate can
be decreased.
Profile
GOP(Group of Pictures) Size is..
I-frame and P-frame can be created for MPEG4 and H.264 video
compression. I-frame(=key-frame) means the whole image data
for one specific scene of video. P-frame is image data which has
been changed information compared to I-frame GOP is made up
of one I-frame and corresponding several P-frames. To improve
video quality, set the number of P-frames smaller and to decrease
image size, set the number of P-frames bigger.
The profile defines the subset of bit stream features in an
H.264 stream, including color reproduction and additional
video compression.
Baseline
Main
A simple profile with a low compression ratio.
An intermediate profile with a medium compression ratio.
High
A complex profile with a high compression ratio.
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Smart Bitrate Control
Off
CVBR (Framerate priority)
Does not use the Smart Bitrate Control.
This Mode is for cameras which do not want absolute any
frame drop, but still want to get lower bitrate. It has
limitation when the Target bitrate is set to be very low,
but actual motion is big or scene is very noisy.
CVBR (Quality priority)
When the Target bitrate is set to very low, and motion is big,
then LBR will try to drop frames, and make the final fps to
be lower, so that it can save its and make the output frames
to have better quality.
CBR
This Mode is a CBR alike mode which is close to traditional
security IPCAM, and it's not designed for LBR, It's provided
as an option in LBR library just to help comparison.