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Software video compression is a software processing of a digital video stream in order to reduce its size. Compression is performed according to a specific software algorithm.
Axxon PSIM uses a 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, depending on the video signal features and compression rate).
Video signals from IP 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 well. That is why Axxon PSIM compresses the video signal in two modes only: in recording to disk mode and transmitting to the Remote Workstation mode. The video signal isn't compressed before being displayed on the monitor installed on the Server.
Before the compressed video signal is displayed on the monitor, it is decompressed beforehand. Decompression is automatically performed when video signals are displayed (both in real time and when playing back video recordings from the Server archive) at Remote Workstations and when video recordings are played back on the Server.
If video resolution on the Monitor is less than the resolution of the compressed video signal, Axxon PSIM partly decompresses 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, H264svc, JPEG2000 codecs. Partial decompression isn't supported for H263, H264avc, and Mpeg2 codecs. Only FPS reduction is supported for H264svc-t codec.
Description of the used decompressors is given in the table:
Decompressor | Description |
|---|---|
FfmpegAllInOneDecoder | A module with a set of Ffmpeg library decoders (with an open source code). It allows converting multimedia data compressed by MxPEG, MPEG2, MPEG4 and Motion JPEG codecs |
H264InterlacedIppDecoder H264IppDecoder MPEG2IppDecoder MJPEGIppDecoder MPEG4IppDecoder | Decompressors included into the Intel Integrated Performance Primitives (Intel IPP) library. A compression format is specified in the decompressor name |
H264SvcEx | A decompressor for converting video signals in H264Svc format received from Stretch devices into H264Avc format |
| H264SvcTex | A decompressor for converting video signals in H264Svc-t format received from VIVOTEC devices into H264Avc format |
MxPEG Mobotix | A decompressor for converting video signals received from Mobotix devices |
Motion Wavelet 7.1 | A decompressor for wavelet-converting video signals |
BOSCH | A decompressor for converting video signals received from BOSCH devices |
| Intel Quick Sync | A decompressor based on QuickSync technology that decodes H.264 video in hardware using Intel's embedded graphics processor, thus significantly reducing CPU load. To enable operation of this decompressor, you must enable the embedded graphics card in BIOS and install the latest Intel drivers. The maximum resolution differs depending on Intel Quick Sync version, for more information, see https://www.intel.com/ |
| Nvidia decoder | A decompressor for converting video signals using the GPU of the video card, which reduces the load on the Server CPU |
Note
When you use decompressors included in the Intel IPP library, video image defects can occur at some resolutions. In such cases, we recommend using video resolution divisible by 16 (for example, 1280x720 or 1360x768) or selecting another decompressor.
Compression and decompression algorithms are specified on the settings panel of the Camera object using the Compressor and Decompressor list, respectively (see The Settings panel of the Camera object), 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 specified in the camera settings is used when a video signal is displayed on a video surveillance monitor and for detectors operation.
Attention!
By default, you cannot select compression and decompression algorithms, and Compressor and Decompressor drop-down lists aren't available for editing. To enable this feature, set the 1 value for the EnableCodecSettings registry parameter (see Registry keys reference guide).
Note
In the multistream mode (see Configuration of multistream video), you can select the codec and configure the video signal quality separately for each video stream on the settings panel of the Camera object on the Video stream tab.
If you don't select the compressor/decompressor (default value) on the settings panel of the Camera object or select the inapplicable one, Axxon PSIM automatically selects the first compressor/decompressor in alphabetical order. If it is also inapplicable, the next compressor/decompressor in alphabetical order is selected, and so on, until an applicable one is selected.
Note
When you use WS7 and WS17 video capture cards, we recommend leaving the Decompressor field blank, or using Motion Wavelet decompressor. If you select another decompressor, then Axxon PSIM operation isn't guaranteed.
Attention!
If you are not satisfied with the automatic decompressor selection, you must select a suitable decompressor yourself.
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