Axis Video Server User Manual

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Contents

Axis Video Server User Manual Manual pdf 14 page image

14 Axis video server - Video and audio streamsVideo and audio streamsThe Axis video server provides several different video and audio stream formats. The typeto use depends on your requirements and on the properties of your network.The Live View page in the Axis video server provides access to Motion JPEG and MPEG-4video and audio streams, as well as to single JPEG images. Other applications and clientscan also access these video and audio streams/images directly, without going via the LiveView page.Video stream typesMotion JPEGThis format uses standard JPEG still images in the video stream. These images are thendisplayed and updated at a rate sufficient to create a stream that shows constantly updatedmotion.The Motion JPEG stream provides excellent image quality and access to each and everyindividual image contained in the stream.Note also that multiple clients accessing Motion JPEG streams can use different imagesettings.MPEG-4This is a video compression standard that makes good use of bandwidth, and which canprovide high-quality video streams at less than 1 Mbit/s.The MPEG-4 standard provides scope for a large range of different coding tools for use byvarious applications in different situations, and the Axis video server provides certainsubsets of these tools. These are represented as Video object types, which are selected foruse with different viewing clients. The supported video object types are:• Simple - sets the coding type to H.263• Advanced Simple - in Axis products, this sets the coding type to MPEG-4 Part 2AMC (AXIS Media Control) supports both object types, whilst e.g. QuickTime™ requires theSimple object type.When using MPEG-4 it is also possible to control the bit rate, which in turn allows theamount of bandwidth usage to be controlled. CBR (constant bit rate) is used to achieve aspecific bit rate by varying the quality of the MPEG-4 stream. When using VBR (variablebit rate), the quality of the video stream is kept as constant as possible, at the cost of avarying bit rate.