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Firmware User
’s Manual V6.04.15
Compression
The section “Compression” allows the user to define the compression settings of the video stream 1 and stream 2. The purpose of compression is to reduce the bandwidth and
VMS storage consumption.
Usually the stream 1 is configured to be the best quality stream for NVR recording purposes while the stream 2 is configured to be with the basic quality for the live view of NVR, to minimize the computing power of NVR used for video decoding.
Parameters
Encoder Type
H.264 Profile
VGA Aspect Ratio
Description
There are two encoder types available: H.264 (High Profile) and
MJPEG.
This item is available only if the Encoder Type is H.264.
The H.264 Profile defines the video compression scheme: High
Profile , Main Profile , and Baseline . These schemes vary from least compressed, Baseline , to most compressed, High Profile . By default, the H.264 Profile is High Profile , which provides the most compression with the best video quality, but more computing power.
Some third-party video management system has longer latency or takes more time to decode High Profile compression scheme, in this case, you can select Main Profile or Baseline . In order to get the same video quality, you can select a higher bit rate with lower compression; this is the same as having a lower bit rate with a High
Profile. For example, a video on High Profile with 2M bit rate will have the same video quality as a video with Baseline Profile at 3.5M bit rate.
It is used to define the aspect ratio of VGA stream – it can be either
4:3 ratio (640x480) or 16:9 ratio (640x360). When “Auto Detected” is chosen, the VGA stream will follow the ratio of the higher resolution stream, to ensure the identical view of stream 1 and stream 2.
Firmware User
’s Manual V6.04.15
Resolution
Frame Rate
Video Bit Rate Mode
(only for H.264)
Video Max Bit Rate
(only for H.264)
Video Bit Rate
(only for H.264)
Quality
Depending on the camera model, the number of available resolutions may be different. The default resolution setting of the camera may not necessarily be the maximum resolution of the camera. If the user wants to use the maximum resolution, it is possible to do it here. The maximum possible resolution of the stream 2 will be smaller than stream 1.
Defines the amount of frames per second.
Under “Constant Bit Rate” mode (CBR), the camera keeps the stable bitrate regardless of the complexity of the scene. Under this mode, the video quality may vary if the bit rate value is set too low. It is easier to do storage and network bandwidth consumption estimations under this mode compared to Variable Bit Rate mode.
Under “Variable Bit Rate” mode (VBR), the camera will keep the video quality stable while the bit rate may occasionally go up or down, depending on the complexity of the scene.
Defines the upper limit of the bitrate (only available under CBR mode).
The bitrate will be floating slightly under that limit. For example, if the limit is set as 2M, the bitrate will be floating around 1.6~2.0 Mbps.
If the Video Max Bit Rate is chosen as
“Unlimited”, then the “Video Bit Rate” selection box will appear that defines the bit rate level.
Under CBR mode, when Video Max Bit Rate is chosen “Unlimited”, the user can define the AVERAGE bit rate. For example, if the Video
Bit Rate is chosen 2M, then occasionally, the actual bit rate may go below or beyond 2M, but in the long run, the average bit rate will be very close to 2M. This mode allows the most accurate storage estimations, however, while planning the bandwidth, please consider the occasional peaks of bit rate.
H.264 Compression:
Under VBR mode, the bit rate will be floating while the video quality will be stable and follows the quality standard set by the user. The user can choose either “High”, “Medium” or “Low” quality. The higher is the quality level, the more bit rate the camera will use to achieve the target quality.
MJPEG Compression:
The user can define the quality with the numeric scale from 1 to 100.
The default MJPEG quality is 60. The higher is the quality level, the more bit rate the camera will use to achieve the target quality.
Firmware User
’s Manual V6.04.15
GOP
(only for H.264)
Under VBR mode it is possible to adjust the GOP length - that is the occurrence rate of I-frames. By default, there is one I-frame per second. For example, in case of 30fps, there will be 1 I-frame and 29
P-frames every second by default. When the GOP is changed to “1
I-frame per 5 seconds ”, then there will be one I-frame, followed by 149
P-frames. In case of the static scenes, long GOP can further minimize the bandwidth and storage consumption.
After changing any of the items above, press Apply to save the changes. The Reset button undoes the changes that had just been made but not Applied yet.
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