N.Bloshkin: Новая страница: «== '''Solution Concept''' == To address the issue, it was decided to create an automatic "Black Screen Detector". It notifies of problems with content on the device and alerts about the occurred situation in the personal account.
{{Note|This functionality is not available to the user in the personal account and needs to be activated separately.|warn}} === '''Operating Principle''' === Every client/company has its own ID associated with the server. This I...»

2023-08-08T14:36:50Z

Новая страница: «== '''Solution Concept''' == To address the issue, it was decided to create an automatic "Black Screen Detector". It notifies of problems with content on the device and alerts about the occurred situation in the personal account. {{Note|This functionality is not available to the user in the personal account and needs to be activated separately.|warn}} === '''Operating Principle''' === Every client/company has its own ID associated with the server. This I...»

Новая страница

== '''Solution Concept''' ==
To address the issue, it was decided to create an automatic "Black Screen Detector". It notifies of problems with content on the device and alerts about the occurred situation in the personal account. 
{{Note|This functionality is not available to the user in the personal account and needs to be activated separately.|warn}}
=== '''Operating Principle''' ===
Every client/company has its own ID associated with the server. This ID is indicated in the personal account, and all the company's devices are linked to it. 
After activating the functionality, the server sends an "event" to the devices at specific time intervals. 
When initiating the "event", the device checks for the presence of a "black" screen using the detector, taking a screenshot during the launch. 
After launching the detector, two specific results can be obtained:
* After initiating the "event", no black screen is detected - the system continues to operate in normal mode.
* After initiating the "event", a black screen is detected - the server sends a secondary, verification "event". 
'''The interval for resending the "event" is 10 seconds.''' 
If a black screen is detected again during the second check, the server sends an email alerting about the issue.
{{Note|The specified email should be linked to the server.|warn}}
=== '''Preparation ''' ===
The system administrator must configure the server application based on two parameters:
* Launch and operation of the "black screen" detector
* Setting up email alerts for detected errors
=== '''Operating Principle ''' ===
If the server application detects a black screen, it sends an email. The result of this check will be an email notification about the issue. 
To confirm the functionality check via the personal account, the system administrator can set a black picture. The server continues to send notifications until the problem is resolved or the functionality is turned off. 
Subsequently, the system administrator must take measures to resolve the issue.
=== '''Nuances and Subtleties in Functional Operation''' ===
1. For correct operation, it is necessary for the placeholder with a white dot to be perceived as a black screen. Therefore, an absolute check is not used. 
2. '''It's relevant only during video playback. ''' If there are root rights on the device, the detector works fine. However, if there are no root rights on the device, the detector won't be able to take a screenshot. 
'''Exceptions:''' 
Screenshot is available:
* If the application is signed with the "developer's signature" (rights level – Signage).
* Some devices (Vestel, Hikvision, Phillips) can take a screenshot without root rights due to firmware features.
3. If a user tries to take a screenshot without root rights, an "empty screenshot" is created with the inscription "Video is playing. No rights to take a screenshot". 
4. Information from the server to the developers is sent through an "event". Inside the sent "event", the server awaits a callback from the developers. 
5. The default "Callback" timeout on the server is 30 seconds.

Translations:"Детектор" черного экрана (Системный администратор)/3/en - История изменений