Player Software is an application used to view recorded or live surveillance video. It often supports playback controls, export options, and compatibility with proprietary formats used by DVRs or NVRs.
This is the generic term used to identify software used to review exported DVR video in a standard PC. The proprietary DVR video format requires this software to play the video in a PC and it is usually exported to the device along with the video. Some manufacturers require you to install the player on your PC. Others run directly from the device (thumb drive, DVD, etc.).