I’d like to get some clarification about metadata handling in the XProtect VMS. In the “Bounding Box Metadata Provider” example, metadata is delivered with the “tt:Frame” element containing the frame timestamp as an attribute. Is this data used in any way by the VMS? For example, if the local VMS device clock differs from the timestamp in the metadata XML, what time will be used by the VMS - the time when the Metadata arrived to the VMS, or the time indicated in the XML content?
Yes. This time is used, assuming time stamp is correctly formatted.
One important note:
Metadata is saved in the same database as video, the database is very highly specialized. One specialization, that is the background for the exceptional performance the database has, is that it can only store data in chronological order. So if you put in metadata fitting 11 am, you cannot put in metadata later fitting 10 am. You can only enter metadata fitting a later time. Metadata is perfect for a flow of analytics data but not for other events where chronological order is not possible.