Axis Communications 215 PTZ-E MPEG-4 Settings, Bit Rate Control, Profile@Level Properties

AXIS 215 PTZ/AXIS 215 PTZ-E - Setup

•Image freeze on PTZ - freeze the image either during pan, tilt, zoom movement or between preset positions only. Once the camera has reached its position, the current image is shown.

MPEG-4 Settings

The AXIS 215 PTZ/AXIS 215 PTZ-E supports the following different MPEG-4 profiles and levels:

Profile@Level	Properties
Advanced Simple Profile @ Level 3b	Max bit rate = 1,5 Mbps
	ISMA compliant
Advanced Simple Profile @ Level 5	Max Bit rate = 8 Mbit/s

Level 5 is preferred if there is enough bandwidth available, as the image quality of the video stream will be better than if level 3 is used. The viewing client must support the profile used for the video stream otherwise the MPEG-4 stream can not be viewed.

Note: AXIS Media Control supports all the configuration possibilities available on this page.

The GOV structure can be set to either I or IP, which describes the type of images included in the video stream, as well as their internal order. The IP-structure generally sends the differences compared to the previous image and far fewer complete images, so this method uses much less bandwidth than the I-structure. The I-structure gives higher frame rates when using a high resolution, but requires more bandwidth.

The GOV length determines the sum total of P-images and I-images in a GOV. Setting the GOV length to a high value saves considerably on bandwidth. However there may be noticeable decay in the image at high values.

Note: GOV = Group of VOPs

VOP = Video Object Plane

Video Object Plane = image

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.

Note: Depending on the amount of motion, the required bandwidth may increase by 1-15% for each frame.

Video Stream

This parameter can be set to frame rate to increase the frame rate by 30% in 4CIF resolution. If the resolution is set to a value lower than 4CIF, the parameter should be set to bandwidth.

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