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Video signal Software video compression is a software processing of a digital video processing aimed at reducing video stream stream in order to reduce its size. Compression is performed according to a specific software algorithm.

Axxon PSIM™ software PSIM uses a specific specially developed MotionWavelet algorithm to compress video signals received from video capture cards. This algorithm allows reducing video stream size by tens of times (from 5 to 30 times, subject to depending on the video signal features and compression rate).

To compress video Video signals from IP -devices, standard (MPEG4) or vendor designed algorithms are in use.devices are compressed using algorithms developed by the manufacturers of these devices or standard algorithms (for example, MPEG4).

When the size of the video stream reduces after compression, the quality of the video stream reduces as wellWith compression, video stream size decreases at the cost of its quality. That is why Axxon PSIM™ software PSIM compresses the video signal in two modes only: in recording to disk recording mode and in transmission transmitting to the Remote Workstation mode. The video signal is not isn't compressed before displaying on a video server monitorbeing displayed on the monitor installed on the Server.

Before displaying the compressed video signal is displayed on the monitor, it is decompressed beforehand. Decompression is automatically performed while displaying when video signals are displayed (both in real - time and archive footage playbackwhen playing back video recordings from the Server archive) at Remote Workstations and when video recordings playback are played back on the videoserverServer.

If video resolution on the Monitor is less than the resolution of the compressed video signal, then Axxon PSIM™ PSIM partly decompresses video (it allows reducing load of CPU that decompresses video). Network load is reduced if the MotionWavelet codec is in use; if other codecs are in use, then the network load stays the same. Partial decompression is supported by the video signal, which reduces the load on the CPU of the decompressing computer. The network load is reduced only when you use MotionWavelet codec, for other codecs it isn't reduced. Partial decompression is possible when you use MPEG4, MJPEG, MXPEG, Motion Wavelet and , H264svc, JPEG2000 codecs. Partial decompression is not supported by isn't supported for H263, H264avc, and Mpeg2 codecs. Only fps FPS reduction is supported by for H264svc-t codec.

Description of the used decompressors is shown given in the table.:

Compression and decompression algorithms are set specified on the settings panel of a the Camera object using the Compressor and Decompressor list correspondingly , respectively (see the Settings The settings panel of the Camera object section), or on the List of cameras tab on the settings panle of the Monitor object (see Selecting and configuring video cameras and Selecting and configuring video cameras in bulk). The decompression algorithm set specified in the camera settings is used when a video signal is displayed on a video surveillance monitor and for detection detectors operation.

If you don't select the compressor/decompressor (default value) is not selected on the settings panel of a the Camera object or select the incorrect inapplicable one is selected, then  Axxon PSIM software automatically selects the first compressor/decompressor in alphabetical order. If it does not fit too, the following one is selected is also inapplicable, the next compressor/decompressor in alphabetical order is selected, and so on, until the correct an applicable one is selected.