Axis Communications 243SA - Manual (Page 14)

14 Video and audio streams
Video and audio streams
The AXIS 243SA provides several video and audio stream formats. The type you want to
use depends on your requirements and the properties of your network.
The Live View page in AXIS 243SA provides access to Motion JPEG and MPEG-4 video
and audio streams, and 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 every individual
image contained in the stream.
Note 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 AXIS 243SA 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™, for example,
requires the Simple object type.
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.
Notes: • MPEG-4 is licensed technology. AXIS 243SA 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.