Axis Communications AXIS 221 user manual Frame rates Motion Jpeg and MPEG-4, Bandwidth

60AXIS 221 - Technical Specifications

Frame rates - Motion JPEG and MPEG-4

The following table shows typical frame rates in frames/second (fps) for Motion JPEG and MPEG-4 video streams from the AXIS 221.

Note that these values are guidelines only - actual values may vary.

Motion JPEG settings:
			Frame rates
•	Viewing in AMC
			Motion JPEG	MPEG-4
•	Compression level = 30%
		640x480	45	30
MPEG-4 settings:		480x360	60	45
		320x240	60	60
•	Viewing in AMC	160x120	60	60

• Compression level = 30%

• Video Object Type = Advanced Simple

• GOV length = 8

• GOV structure = IP*

*Note that setting the GOV structure to use “I-frames only” will increase the frame rate at the expense of the bit rate.

Bandwidth

As there are many factors that affect bandwidth, it is very difficult to predict the required amounts. The settings that affect bandwidth are:

•the image resolution

•the image compression

•the frame rate

•the MPEG-4 object type

•the MPEG-4 GOV structure

•the maximum exposure time.

There are also factors in the monitored scene that will affect the bandwidth. These are:

•the amount of motion

•the image’s complexity

•the lighting conditions.

For MPEG-4, if there is only limited bandwidth available, and if this is more important than the image quality, using a constant bit rate (CBR) is recommended. Use a variable bit rate (VBR) if the image quality needs to be maintained at a higher level. If supported on the network, consider also using MPEG-4 multicasting, as the bandwidth consumption will be much lower.