Canvases, surfaces and displays
ArenaDirector keeps what plays separate from where it physically goes. New users often expect a single setting for both, but each answers a different question and changes at a different time.
A canvas or a bus is what plays, and it exists and works with no hardware attached. An output is the physical destination: a display, an LED surface, an NDI stream or an audio device. You describe an output once, and that description stays the same whichever canvas or bus sends to it. A leg connects the two: it is a canvas's or a bus's claim on one output.
You create and name each output, and you connect outputs to canvases and buses on Patch (see Patch the show). The list describes the venue you will work in, not whatever is plugged into this laptop right now, so on Tuesday you can describe a wall you will drive on Saturday. When you disconnect a device, its row shows as missing in orange and nothing else changes.
| Answers | Changes when | |
|---|---|---|
| Canvas (or bus) | For what destination do I make a picture or a sound mix? | You add a destination to the show |
| Output | What physical device receives it now? | Someone changes the hardware |
Canvas
A canvas is a video destination. It has a size, renders a picture at that size, and works with no screen connected.
So you can build a whole show with no hardware attached, target hot buttons at "Scoreboard" and check the result in the app's preview. The hardware only matters on the day of the event.
Everything in the show refers to the canvas by name, so several hundred hot buttons can target "Scoreboard" without caring what hardware sits behind it. A bus works the same way for sound. See How playback works.
When a show does not use a canvas, you can disable it. Its window closes, but it keeps its outputs reserved so no other canvas can take them.
Hot buttons, cues and rotations that target a disabled canvas keep their configuration and skip that canvas. A video that targets only disabled canvases is skipped entirely, soundtrack included, and a play that shows only on a disabled canvas does not go into the proof of play log.
The leg
On Patch, a leg is a cable. A canvas can have legs to several outputs, and two canvases can each have a leg to the same output. A leg records whether it is driven, which decides whether content reaches that destination.
- An undriven leg on an NDI stream does not publish.
- An undriven leg on a display does not put the canvas on that screen.
That lets you keep an alternative configuration for the same wall without using it. If two canvases have a leg to the same display, switch off Connected on the cable that should not have the display, and that decides which canvas shows.
A leg also records its fit mode, which says what to do when the canvas and the output are different sizes.
- Native does not scale. It draws one canvas pixel per output pixel and centers the result, so a smaller canvas gets a border and a larger one is cropped.
- Fit scales until the whole canvas is visible, which leaves a border on one axis.
- Fill scales until the canvas covers the output and crops whatever falls outside.
When the sizes match, all three modes give the same picture.
A new leg picks its mode from the two sizes: Native when they match and Fit when they differ. That way a new assignment fills the screen the same way it did before you added the leg. This is only the starting value. If you choose a different mode, ArenaDirector keeps your choice and loads it again later.
When the sizes differ, the row says so and shows both sizes. If you then choose Native, the leg shows a flag, so the picture is never cropped without a warning.
The mode belongs to the leg, not to the canvas or the output, and it is the only setting that relates to both. So the same canvas can be pixel-exact on the wall it was made for and scaled to fit a confidence monitor next to it.
You can remove any leg, whatever it targets, and undo any assignment you make.
Every other property of the destination belongs to the output, not the leg: its name, its latency offset and its sync group. You describe them once, and they apply to every canvas or bus that drives the output later. If a different canvas starts sending to a projector, you do not have to measure that projector's latency offset again.
Sync group
Every output starts in one sync group, called House. Outputs in the same group stay synchronized with each other. To keep them in sync, ArenaDirector makes the content early enough for the member that needs it first, so one slow destination sets the response time of the whole group.
Moving that destination to a second group gives the first group its fast response back, but the two groups are then no longer synchronized with each other. Both choices have a real cost, so splitting groups is your decision and ArenaDirector never does it for you. See How playback works.
Surface
A surface describes a physical LED build: the size of one cabinet, the named sections of the build, and how the whole build folds onto a sending card's input. See LED boards.
A surface is a type of output, just like a display. You connect a canvas to a surface on Patch the same way you connect it to a display, and a surface provides a raster as a display does.
- A display gets its raster from the screen, which ArenaDirector reads when you connect the screen.
- A surface has no screen to report it. Its raster comes from your cabinet counts and your fold, and it stays the same size across restarts.
A surfaced canvas has no size that you set. ArenaDirector lays out content in the wall's own pixels, because that is where the sections are. A section is a row of cabinets, so a clip that targets a section fits the shape of that row.
Sponsor text lands pixel for pixel on the boards it was made for, unaffected by the rest of the ring. The fold then sends the picture to the sending card, and the canvas's Resolution value shows what the card receives.
A display is different, because it puts no limits on where content goes. You set the canvas size yourself, and ArenaDirector scales the canvas onto the screen if the sizes differ.
The canvas takes its shape from the surface: the cabinet grid, the named sections that content can target, and the fold. If you pick a different surface for the canvas, all of that moves with it and the show keeps working.
Two canvases can share a surface, and an edit to the surface applies to both.
Display
A display is a physical screen, for example a video board, a projector or the video input of an LED controller.
A display output is a row that you create and connect to one screen. The output and its connection are kept separate on purpose: if you connect it to a different display, every canvas that sends to it follows, and you do not have to assign them again.
Assignments persist. ArenaDirector recognizes the screen after you disconnect it, move it to another port or restart the machine. A screen that is not connected stays in the list as absent, and its canvas returns to it as soon as ArenaDirector detects the screen.
ArenaDirector also notices changes to a connected screen. If you change its resolution, the output shows the new size, and a canvas on that screen fits the new size without a restart.
One output drives one screen. A plain display and an LED surface that folds onto the same sending card cannot both claim the screen, because they would write to the same pixels.
You can assign several displays to a canvas. If more than one of them is connected, the last one assigned wins.
NDI stream and audio device
Two other types of output work the same way but have no screen.
An NDI stream publishes a canvas's picture and sound to the network. You create and name it as a destination in its own right, and no canvas owns it, so one canvas can send to several streams. You can also connect a stream to a different canvas while the receivers keep seeing the same stream. See Publish a canvas over NDI.
An audio device is one stereo pair on a sound card. You add it once as an output, and the bus that should send to it then selects it. See Set up a bus.
The three output states
A canvas is always in one of three states, and ArenaDirector switches between them on its own.
Preview. The canvas renders its picture, and you can see it in the Outputs strip at the bottom of the app. This is always the case, even with no hardware attached.
Floating window. You chose to show the canvas, but none of its assigned displays is connected, so the canvas opens in a window you can move. This is the usual state while you prepare a show on a laptop.
Venue mode. An assigned display is connected, and the canvas covers it full screen with no window frame.
You decide when to show or hide a canvas, and the hardware decides which of the two output states you get. See Show canvases on screens.