Axis Communications 232d+ user manual How to stream MPEG-4, 12AXIS 231D+/232D+ - Video Streams

12AXIS 231D+/232D+ - Video Streams

When using MPEG-4 it is also possible to control the bit rate, which in turn allows control of bandwidth usage. CBR (constant bit rate) is used to achieve a specific bit rate by varying the quality of the MPEG-4 stream. When using VBR (variable bit rate), the quality of the video stream is kept as constant as possible, at the cost of a varying bit rate.

How to stream MPEG-4

Deciding the combination of protocols and methods to use depends on your viewing requirements, and on the properties of your network. The available options in AMC are:

Unicast RTP	This unicast method (RTP over UDP) should be your first	Unicasting is used for video streaming,
	consideration for live unicast video, especially when it	so that there is no video traffic on the
	is important to always have an up-to-date video	network until a client connects and
	stream, even if some images are dropped.	requests the stream.
RTP over RTSP	This unicast method (RTP tunneled over RTSP) is useful	Note that there are a maximum of 20
	as it is relatively simple to configure firewalls to allow
		simultaneous unicast connections.
	RTSP traffic.
RTP over RTSP over HTTP	This unicast method can be used to traverse firewalls.
	Firewalls are commonly configured to allow the HTTP
	protocol, thus allowing RTP to be tunneled.
Multicast RTP	This method (RTP over UDP) should be used for live multicast video. The video stream is always
	up-to-date, even if some images are dropped.
	Multicasting provides the most efficient usage of bandwidth when there are large numbers of cli-
	ents viewing simultaneously. A multicast broadcast cannot however, pass a network router unless
	the router is configured to allow this. It is not possible to multicast over the Internet, for example.
	Note also that all multicast viewers count as one unicast viewer in the maximum total of 10
	simultaneous connections.

AMC negotiates with the camera to determine the transport protocol to use in the order listed above. This order can be changed and the options disabled, to suit specific requirements.