Help and Support
MultiViewer User Guide PDF file
Yes, if a compatible VGA card has being install on your system - using CUDA, all players playback can be offload to GPU, which will reduce CPU usage by 50~60%. List of supported cards can be found here.
Stream should contain more than 2 (stereo) tracks - the codec could be AAC ADTS or AC3 Dolby Digital 5.1 with those extra audio tracks. Multiviewer will automatically detect that during the launch and display VU meter with multiple tracks, if they are present.
In order to exit Multiviewer just press [Esc] button on your keyboard - you will be prompt to confirm quitting.
Few keyboard buttons are dedicated for specific function during program run
[ESC] - exit or quit from running program (Layout Designer, Multiviewer Configuration and Monitoring)
[F1] - shows currently configured links in the pop-up window during the monitoring
[F2] - saves current layout settings in Layout Designer
Yes, DASH streams are supported. Player will display stream type during the monitoring. 
MultiViewer Legacy Website still up and running