Video and audio streams, MPEG-4 | Axis Communications AXIS 241SA

AXIS 241QA/AXIS 241SA - Video and audio streams 13

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

•Advanced 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.