Axis Communications Video Server AXIS 241SA - Manual (Page 13)

13 AXIS 241QA/AXIS 241SA - Video and audio streams
Video and audio streams
The AXIS 241QA/AXIS 241SA provides several different video and audio stream formats.
The type to use depends on your requirements and on the properties of your network.
The Live View page in the AXIS 241QA/AXIS 241SA provides access to Motion JPEG and
MPEG-4 video and audio streams, as well as to single JPEG images. Other applications and
clients can also access these video and audio streams/images directly, without going via
the Live View page.
Video stream types
Motion JPEG
This format uses standard JPEG still images in the video stream. These images are then
displayed and updated at a rate sufficient to create a stream that shows constantly updated
motion.
The Motion JPEG stream provides excellent image quality and access to each and every
individual image contained in the stream.
Note also that multiple clients accessing Motion JPEG streams can use different image
settings.
MPEG-4
This is a video compression standard that makes good use of bandwidth, and which can
provide 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 by
various applications in different situations, and the AXIS 241QA/AXIS 241SA provides
certain subsets of these tools. These are represented as Video object types, which are
selected for use with different viewing clients. The supported video object types are:
• Simple - sets the coding type to H.263
• Ad
vanced Simple - in Axis products, this sets the coding type to MPEG-4 Part 2
AMC (AXIS Media Control) supports both object types, while QuickTime™ requires the
Simple object type. When using MPEG-4 it is also possible to control the bit rate, which in
turn allows the amount of bandwidth usage to be controlled. 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.
Notes: • MPEG-4 is licensed technology. The AXIS 241QA/AXIS 241SA includes one license for the
decoder required for viewing in AMC. Installing additional unlicensed copies of this decoder
is prohibited. To purchase more decoder licenses, contact your Axis reseller.
• All clients viewing the MPEG-4 stream must use the same image settings.