Video player
At any time, you can preview any node in real-time (if the graph preceding it isn’t too complex) in a lightweight video player.

Either use the node menu and click Preview (for a temporary window), or Connect to real-time output (for a persisting window) or hit [P].
For now, DuME uses FFplay as a video player, which is very light and fast, and can play your graph stream in realtime without rendering it to a file, although this may change in the future, or the option to change the player may be implemented later.
This player doesn’t have a user interface to control playblack, but nice shortcuts instead.
[Q]or[ESC]: quit[F]orLeft double click: toggle full screen[P]of[SPACE]: pause[M]: toggle mute[9],[0]: decrease and increase volume respectively[/],[*]: decrease and increase volume respectively[A]: cycle audio channel in the current program[V]: cycle video channel[T]: cycle subtitle channel in the current program[C]: cycle program[W]: cycle video filters or show modes[S]: activate frame-step mode[←],[→]: seek backward/forward 10 seconds or to custom interval if -seek_interval is set[↓],[↑]: seek backward/forward 1 minute[PAGE_DOWN],[PAGE_UP]seek backward/forward 10 minutesRight click: seek to percentage in file corresponding to fraction of width
Options

Default parameters for the video player can be set in the settings of the application, in the Multimedia tab.