Axis Communications Q7411 Camera Accessories User Manual

AXIS Q7411 Video Encoder
Media Streams
Media Streams
The Axis product provides several audio and video stream formats. Your requirements and the properties of your network will
determine the type you use.
The Live View page in the product provides access to H.264 and Motion JPEG video streams, audio streams and to the list of available
stream proles. Other applications and clients can access video and audio streams directly, without going via the Live View page.
How to Stream H.264
H.264 can, without compromising image quality, reduce the size of a digital video le by more than 80% compared with the Motion
JPEG format and as much as 50% more than the MPEG-4 standard. This means that much less network bandwidth and storage space
are required for a video le. Or seen another way, much higher video quality can be achieved for a given bit rate.
Deciding which combination of protocols and methods to use depends on your viewing requirements, and on the properties of
your network. The available options in AXIS Media Control are:
Unicast RTP
This unicast method (RTP over UDP) is used
for live unicast video, especially when it is
important to have an up-to-date video stream,
even if some frames are dropped.
This unicast method (RTP tunneled over RTSP)
is useful as it is relatively simple to congure
rewalls to allow RTSP trafc.
RTP over RTSP over HTTP
This unicast method can be used to traverse
rewalls. Firewalls are commonly congured to
allow the HTTP protocol, thus allowing RTP to
be tunneled.
Unicasting is used for video-on-demand
transmission so that there is no video trafc
on the network until a client connects and
requests the stream.
Note that there are a maximum of 20
simultaneous unicast connections.
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 frames are dropped.
Multicasting provides the most efcient usage of bandwidth when there are large numbers of
clients viewing simultaneously. A multicast cannot however, pass a network router unless the
router is congured 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 20
simultaneous connections.
AXIS Media Control negotiates with the Axis product to determine the transport protocol to use. The order of priority, listed in the
AMC Control Panel, can be changed and the options disabled, to suit specic requirements.
H.264 is licensed technology. The Axis product includes one H.264 viewing client license. Installing additional unlicensed
copies of the client is prohibited. To purchase additional licenses, contact your Axis reseller.
This format uses standard JPEG still images for the video stream. These images are then displayed and updated at a rate sufcient
to create a stream that shows constantly updated motion.
The Motion JPEG stream uses considerable amounts of bandwidth, but provides excellent image quality and access to every image
contained in the stream. The recommended method of accessing Motion JPEG live video from the Axis product is to use the AXIS
Media Control in Internet Explorer in Windows.
AXIS Media Control (AMC)
AXIS Media Control (AMC) in Internet Explorer in Windows is the recommended method of accessing live video from the Axis product.