Axis 212 PTZ-V User Manual page 18

Low Light Behavior
These settings determine how the camera will function in low light conditions. Adjustments made here affect image quality
and are basically a measure of how much noise to allow in images. Please use the online help
each individual setting.
• Exposure priority
• Max exposure time
• Max gain
Please see the online help
MPEG-4
GOV Settings - The GOV settings control the composition of the MPEG-4 video stream. Setting the length to a high value
saves considerably on bandwidth. The Cyclic refresh parameter gives a smoother bit rate and can be useful if bandwidth is
limited.
Bit Rate Control - Limiting the maximum bit rate is a good way of controlling the bandwidth used by the MPEG-4 video
stream. Leaving the Maximum bit rate as unlimited will provide consistently good image quality, but at the expense of
increased bandwith usage whenever there is more activity in the image. Limiting the bit rate to a defined value will prevent
excessive bandwidth usage, but images will be lost when the limit is exceeded.
Note that a maximum bit rate can be used for both variable and constant bit rates.
The bit rate type can be set as Variable Bit Rate (VBR) or Constant Bit Rate (CBR). VBR will adjust the bit rate according to the
images' complexity, thus using a lot of bandwidth for a lot of activity in the image and less for lower activity in the monitored
area.
CBR allows you to set a fixed Target bit rate that will consume a predictable amount of bandwidth, and which will not change
whatever happens in the image.
As the bit rate would usually need to increase for increased image activity, but in this case cannot, the frame rate and image
quality will be affected negatively. To go some of the way towards compensating for this, it is possible to prioritize either the
frame rate or the image quality whenever the bit rate would normally need to be increased. Not setting a priority means the
frame rate and image quality will be affected approximately equally.
MJPEG
Frame Size Control - In some situation the image size may get quite large due to low light or complex scenery. Adjusting the
maximum frame size is a good way of controlling the bandwidth and storage used by the MJPEG video stream in these
situations. Leaving the frame size at Unlimited will provide consistently good image quality at the expense of increased
bandwidth and storage usage during low light. Limiting the frame size will prevent excessive bandwidth and storage usage,
but image quality will suffer. To prevent increase in bandwidth and storage usage, the maximum frame size should be set to
an optimal amount.
During ideal light conditions follow these instructions to optimize frame size:
1. Click the View button and a pop-up window appears with Frame size and Compression in the text field.
2. Note the current frame size. To calculate a maximum frame size add 10 - 20% to the current frame size.
3. Enter the calculated frame size in the Limited to... field.
4. Verify the quality of the image in low light. Increase the maximum frame size if needed.
Note:
The maximum frame size allowed increases compression in order to maintain a low frame size starting at the
compression value set under Image Settings > Image Appearance > Compression. When compression is 100, the
image cannot be made smaller. You may also need to adjust the Resolution setting if a smaller frame size is needed.
for more information on these settings.
AXIS 212 PTZ/-V - Video and Image settings
18
for more information on