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Patterns

 Algorithm of calculation

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Patterns

 Algorithm of calculation

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Patterns

 Algorithm of calculation

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for manufacturers, distributors and skilled designers

 

IP Camera CCTV Calculator calculates according to the following algorithm:

 

1. From a pattern, assigned to a camera, according to specified compression and frame rate, a real traffic value (Average_bytes_per_sec_of_test_frames) is chosen. This traffic was created by video stream of specified in the pattern resolution (Horizontal_resolution_of_test_frames' * 'Vertical_resolution_of_test_frames' ).

 

An appropriate pattern can be assigned for each camera manually or automatically if the name of the camera model is listed in CAMERA_MODELS list of the pattern.

Compression type of camera corresponds to the attribute Compression_name in the pattern.

Compression level of camera corresponds to the attribute Level_name in the pattern.

If the camera's frame rate is not equal exactly to one of Fps attribute values in FPS_LEVELS sections, then the value of real traffic Average_bytes_per_sec_of_test_frames is averaged from the closest by Fps values FPS_LEVELS sections.

 

2. The obtained traffic value is recalculated from given in the pattern resolution of test frames (Horizontal_resolution_of_test_frames' * 'Vertical_resolution_of_test_frames) to camera's resolution directly proportional to the ratio of the camera's number of pixels  to the number of pixels of test frames in the pattern.

 

3. Obtained intermediate value of the traffic is multiplied by the correction factor of the PIXEL_COUNT_FACTORS section, correcting the traffic according to the camera's number of pixels.

 

4. Obtained intermediate value is multiplied by the Scene_compexity_factor and the Scene_activity_factor, Black_and_white_factor (if the camera is black-and-white),  the Noise_factor.

 

5. Obtained intermediate traffic value is multiplied by the General_corrective_factor, the General_corrective_addon is added to the traffic value. Obtained intermediate traffic value is multiplied by the Compression_corrective_factor, to the value the Compression_corrective_addon of selected compression type is added.

 

6. From the obtained intermediate traffic value the average frame size is calculated by dividing the traffic by the frame rate.

 

7. At this stage, an opportunity to manually enter the known frame size value is offered, or you can leave the computed value.

 

8. Calculated or entered value of the average frame size is converted into the traffic again, by multiplying by the frame rate.

 

9. The audio traffic is added, if the Sound  box is marked.

 

10. Again, an opportunity to manually enter the known traffic value is offered, or you can leave the computed value.

 

11. By the same way (step 1..step 10), IP Camera CCTV Calculator calculates 3 traffic values: Viewing, Recording and Alarm recording.

 

12. Then the required Bandwidth is calculated in dependence of the Summ/Max box state.

If the Sum/Max checkbox is checked then the Required bandwidth equals to the sum of traffics of all generated streams (Viewing. Recording, Alarm recording).  If the camera generates several independent streams, the Sum/Max checkbox must be checked.

 

If the Sum/Max checkbox is not checked then the Required bandwidth equals to the maximal value of traffics of all generated streams (Viewing. Recording, Alarm recording). If the camera generates only one stream, which switches quality parameters according to timetable or by events, the Sum/Max checkbox must be not checked.

 

13. An opportunity to manually enter the known Bandwidth value is offered.

 

14. The Required disk space to provide specified storage time is calculated by the formula:

 

Ds=(Fr*(Tr/24)+Fa*(Ta/100%))*(1/1024)*(1/1024)*(1/8)*60*60*24*Ts

 

Where:

 

Ds - disk space, Gigabytes

Fr - traffic of recording stream, kbit/s

Tr - expected record time, hours/day

Fa - traffic of alarm recording stream, kbit/s

Ta - expected alarm time, %

Ts - storage time, days

 

15. Thus (step 1..step 16), IP Camera CCTV Calculator  calculated 3 traffic values: Viewing, Recording and Alarm recording as well as Bandwidth and Required disk space for each camera in the project.

 

16. Finally IP Camera CCTV Calculator adds calculated values for the cameras visible in the table, obtaining total values of the Traffics, Bandwidth and Disk space.