QNAP Security VioStor NVR (Version: 4.1.2) - Manual (Page 173)

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The multi-stream feature in firmware v4.1.0 has been enhanced. Users can configure
stream properties after selecting “User Defined” from the drop-down list on the user
interface, and users can choose stream properties based on their needs.
Please note that in the Multi-Stream Profile, the default value is “System-Configured”.
Starting from firmware 4.1.0, User defined multi-stream is supported in VioStor NVR
System. Currently, cameras that have been tested for user defined multi-stream include: