Axis Communications 214 PTZ 214 PTZ - User's Manual - Page 11

AXIS 214 PTZ 11 Video and Audio Streams The AXIS 214 PTZ provides several different image and video formats. The type you want to use depends on your requirements and on the properties of your network. The Live View page in the AXIS 214 PTZ provides access to Motion JPEG and MPEG-4 video 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 uses considerable amounts of bandwidth, but also 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 low bandwidth (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 214 PTZ 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, as used by e.g. QuickTime™ • Advanced Simple - sets the coding type to MPEG-4 Part 2, as used by AMC (AXIS Media Control) 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 214 PTZ includes one viewing client license. Installing additional unlicensed copies of the viewing client is prohibited. To purchase additional licenses, contact your Axis reseller. •All clients viewing the MPEG-4 stream must use the same image settings. Audio Stream Types The audio stream types for audio are: • G.711 - International standard for encoding wired-telephone audio. Uses PCM samples to compress audio where higher signal values are compressed more than lower values. In Axis products, this sets the coding type to μ-law 64 kbit/s. • G.726 - Uses PCM samples to code the difference between samples (ADPCM). Reduces bandwidth without losing too much useful audio. In Axis products, this sets the coded bit rate to 24 or 32 kbit/s. All stream types are ITU-T standards and operate on frequencies of up to 4 kHz.