Assessments - 4, GPA: 4.3
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A benefit of unicasting is that if one stream fails, it only affects one user. •Multicast is bandwidth-conserving technology that reduces bandwidth usage by simultaneously delivering a single stream of information to multiple network recipients. This technology is used primarily on delimited networks (intranets), as each user needs an uninterrupted data flow and should not rely on network routers. AXIS Media Control (AMC) The recommended method of accessing live video and audio from the AXIS 241QA/AXIS 241SA is to use the AXIS Media Control (AMC) in Microsoft Internet Explorer in Windows. This ActiveX component is automatically installed on first use, after which it can be configured by opening the AMC Control Panel applet from the Windows Control Panel. Alternatively, right-click the video image in Internet Explorer. How to stream MPEG-4 Deciding on the combination of protocols and methods to use depends on your viewing requirements, and on the properties of your network. Setting the preferred method(s) is done in the control applet for AMC, which is found in the Windows Control Panel. When this has been set, AMC will test all the selected methods in the specified order, until the first functioning one is found. This method (actually RTP over UDP and RTSP over TCP) should be your first consideration for live video, especially when it is important to always have an up-to-date video stream, even if some images do get dropped. This can be configured as multicast or unicast. Multicasting provides the most efficient usage of bandwidth, especially when there are large numbers of clients viewing simultaneously. Note however, that a multicast broadcast cannot pass a network router unless the router is configured to allow this. It is thus not possible to multicast over the Internet, for example. Unicasting should be used for video-on-demand broadcasting, so that there is no video traffic on the network until a client connects and requests the stream. However, if more and more unicast clients connect, the server will at some point become overloaded. There is also a maximum of 20 simultaneous viewers to be considered. This unicast method is RTP tunneled over RTSP. This can be used to exploit the fact that it is relatively simple to configure firewalls to allow RTSP traffic. These two methods can also be used to traverse firewalls. Firewalls are commonly configured to allow the HTTP protocol, thus allowing RTP to be tunneled. Other methods of accessing the video stream Video/images from the AXIS 241QA/AXIS 241SA can also be accessed in the following ways: •If supported by the client, the AXIS 241QA/AXIS 241SA can use Motion JPEG server push to display video. This option maintains an open HTTP connection to the web browser and sends data as and when required, for as long as required. •As single JPEG images in a browser. Enter the path: •Windows Media Player. This requires AMC and the MPEG-4 decoder to be installed. The paths that can be used are listed below, in the order of preference. Notes: Other MPEG-4 clients Although it may be possible to use other clients to view the MPEG-4 stream, it is not guaranteed to work in all cases. For some other clients, such as QuickTime™ the Video Object Type must be set to Simple. It may also be necessary to adjust the advanced MPEG-4 settings. To access the video stream from e.g. QuickTime™ the following path can be used: rtsp://