LivePremier Plus user guide

LivePremier Plus is a local app that puts extra panels inside an Analog Way LivePremier Web RCS session, drawn in Web RCS’s own design language so they read as part of the product rather than as a bolt-on.

• VPU Map — the device’s mixing-resource allocation, drawn as a budget. Which units are fitted, who holds them, what is spare, and what a staged preconfig would change.
• Console — a lighting-desk command grammar for a video switcher.
• Timeline — a theatre-style cue stack that advances on one GO, with per-cue fade, delay and follow times.
• MIDI Mapping — a control surface driving the switcher, from the page itself.
• Arithmetic in the vendor’s own numeric fields — type 1080-80 into a layer width and get 1000.

It rides the vendor app’s own WebSocket. No second connection to the device, no replacement UI, and nothing to install in the browser.

Before you rely on this: the panels render inside a real Web RCS session and the device store mirrors live — verified through this proxy against LivePremier Simulator 6.2.73, along with cue-stack persistence and the whole setup flow. The VPU map has been read from a live Aquilon C and is tested against that capture, including Optimized mode, interleaved output links, and a staged preconfig differing from the running one.

Nothing has ever been written to that device, the timeline has only ever fired at a simulator, and no panel has been driven live against physical hardware in a browser. That is the first thing to try.

Built with AI assistance, directed and reviewed by a human author.

Running it

Needs Node 20 or newer and has no dependencies to install.

npm start

Then open http://127.0.0.1:8535/ and give it the switcher’s address. That address is remembered.

npm start -- --device 192.168.2.142

There is a desktop app too — a tray launcher with an interface and port picker.

On binding wide. The default is loopback for a reason: this proxy is an unauthenticated route to a switcher’s entire control surface. --host 0.0.0.0 hands that to everyone on the network. Do it deliberately, not by habit.

Open it through the proxy, not at the switcher

If you open the switcher’s own address directly, the panels are not there and MIDI will not work. Web MIDI is a secure-context API; http://127.0.0.1:<port> counts as one and a plain-HTTP LAN address does not. The panel says so rather than failing silently.

Console

Verb first, then objects, innermost scope last. Every keyword abbreviates to any unambiguous prefix; Enter executes and nothing is sent before it.

Recall Screen 1 Memory 5
R Sc 1 Th 4 Me 5 Pre          the same command
Store Master 12
Take Screen 1

The line parses as you type and shows what it will do — Recall 3 → Screen 1 Preview — before anything reaches the device. Tab completes; ↑ recalls history.

This panel owns no grammar. Every token, rule and device path comes from mynah’s own build output — the same artefact its Companion module vendors. If a command means the wrong thing, the fix is in mynah.

That is worth more than tidiness: mynah’s compiler and this repo’s command builder were arrived at independently, and they emit byte-identical store paths for the commands both know. Two independent derivations agreeing is the strongest evidence either is right, and it stays true only while nobody re-types the grammar here.

MIDI Mapping

Under Virtual RC400T. Pick an input, an output for feedback, and a controller profile; press Start. Faders, encoders and buttons then drive the selected layer.

The engine is awj-surface’s, vendored whole along with its stock profiles — X-Touch/Mackie, APC40, MIDIcon 2 and Pro, plus a generic learn profile.

Soft pickup is the behaviour worth knowing. A non-motorised fader will not move a live value until it has swept through that value, so picking up a fader mid-show cannot jump a layer’s opacity. The panel shows the hold-off rather than looking broken — if a fader appears dead, that is what you are seeing.

Arithmetic in numeric fields

Type an expression into one of Web RCS’s own numeric fields and it is evaluated when you commit — on Enter, or on leaving the field:

+ - * / ( ) and decimals, with the usual precedence. The result is clamped to the field’s own declared range and rounded to its step, so a width of 9000+1000 lands on 8192 rather than being refused.

Nothing else about the field changes: the vendor still validates it, still decides what to send, and still drags the other axis along if the aspect lock is on.

Where it applies is narrow on purpose. Only fields the vendor itself marks as numeric by putting min, max and step on them. That excludes everything that must not be touched — labels have no step, and neither does the transition-time field, whose 00:01.000 would be mangled by anything treating : as arithmetic.

Opacity and zoom are deliberately excluded. They are real number inputs, and a number input discards anything it cannot parse — after typing 1080-80 the browser reports an empty value, and the expression is visible on screen but unreadable from script. Winning arithmetic there would mean mutating a vendor element’s type on every focus, in a UI driving a live show. Not a good trade.

There is no eval anywhere in this path; anything the parser does not fully understand is refused rather than guessed at.

The demo environment

npm run demo

brings the whole thing up against a LivePremier Simulator, with a real Aquilon C’s resource map folded in and an example cue stack loaded, so every panel has something real to show without a switcher in the room.

The simulator has no VPU at all, so the panel against a bare one correctly reports there is nothing to draw; the demo supplies that from the recorded capture — 32 of 64 mixers fitted, 26 allocated, one screen in Optimized mode, and a staged preconfig differing in 26 mixers. Everything outside that stays the simulator’s own live state, so cues fired from the timeline really do go on the wire.

It refuses to run against anything that is not loopback. The demo splices a store subtree and seeds a cue stack, and “I thought it was the simulator” is exactly the mistake worth making impossible.

The demo’s cue stack lives in a temporary directory and is deleted on exit; your own is never touched.

If something is wrong