IP Camera CCTV Calculator

Patterns

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Patterns

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Video compression technologies are developed constantly together with increasing computing power of camera chips. In different CCTV equipment different compression algorithms and their versions can be used. Even quantity, names and "influence" of compression levels of different equipment can differ. It makes impossible creation of an universal calculator whose results would be equally correct for any equipment and even for different generations of equipment from the same manufacturer.

 

Correct calculator should take into account features of used equipment. For this reason calculators from camera manufacturers are valued highly. The best example of such calculator is a calculator from Axis Communication, Axis Design Tool.

 

But what will you do, if in one project cameras of different manufacturers are used, or the manufacturer does not offer any calculator?

 

To take into account features of any equipment, compressions and scenes in IP Camera CCTV Calculator, patterns are used.

 

A pattern is a structured text file in XML format, contains results of practical measuring traffic of cameras at set of compression algorithms and levels, at different frame rates and for different scenes.

 

Patterns can be edited by any text editor or XML editor.

Patterns can contain results of traffic measurements for some averaged scene with correction factors for its complexity and activity, and the results of traffic measurement for real scenes.

If results for real scenes are used, it is recommended to save examples of these scenes as video files.

 

Special patterns can be created by skilled users or manufacturers (distributors) of CCTV equipment by practical measurements of traffic for certain equipment, scenes and compression algorithms.

Thereafter during the calculation, a designer should choose the pattern name in the Pattern field. As a result, values from the pattern will appear in the drop-down lists of fields: Pixels, Compression type, Compression level.  Calculation will be carried out on the basis of data from this pattern.

 

If a good calculator from a camera manufacturer is available, for these cameras it is possible to create a pattern without practical measurements, just having copied results produced by the specialized calculator.

 

The default pattern is based on averaged data from the Axis Design Tool.

 

The patterns can include a list of supported camera models.

If the model name in the Model field coincides with any model name in any pattern, then this pattern will be assigned to the Pattern field, calculations for this camera will be performed according to this pattern.

In this case a designer even has not to remember what pattern should be used for each camera model. The necessary pattern will be used automatically as a result of choosing model name in the Camera>Model field.

 

According to type and level of compression, frame rate, scene parameters, IP Camera CCTV Calculator chooses from the pattern experimentally obtained traffic value and correction factors. From the traffic value, IP Camera CCTV Calculator calculates expected average frame size  and other results (required bandwidth and disk space). Thus the maximum possible calculation accuracy can be achieved.

 

Different cameras in one project can be assigned different patterns. In each pattern  many compression types, compression levels and scenes can be described.

 

The files of patterns are stored in the Program files/IP_Camera_CCTV_Calculator/Patterns/ directory. For adding a new pattern it is necessary to copy an existing file, edit it in any text editor and save it in the same directory, but under other name.

 

See further (for manufacturers, distributors and skilled designers): The Structure of pattern file, Algorithm of calculation