The LivePremier OSC dictionary

The five rules

1. The address is the target; the argument is only the value

Everything about what is being addressed is in the path, so a button with a fixed address and no argument still means something specific. That is the difference between a TouchOSC layout you draw once and one that needs logic behind every control.

2. A trigger fires on a non-zero argument, and on none at all

Surfaces send 1 on press and 0 on release. A take that fired on both would fire twice per press, and the second one is the one nobody meant. A release is logged as ignored rather than dropped, so a surface sending something correctly disregarded still shows up when you are wondering why nothing happened.

3. A recall never defaults to program

/lp/screen/1/memory/5/recall goes to preview. Reaching air always costs the explicit word — /program, or a take. An under-specified address must not be able to change what an audience is looking at.

4. Units are the device’s, unless the address ends /norm

A fader sends 0–1. The device wants 0–256 for opacity and −2000000 to 2000000 for a position. Which of the two 0.5 meant cannot be worked out from the value — it is a perfectly good literal position, half a pixel left of centre, and the middle of a fader’s throw. So it is said in the address instead. Two addresses, no guessing.

Without /norm the value goes as given and is clamped to the parameter’s own range. With it, 0–1 is scaled across that range; an enum walks its values, so a knob over position/anchor steps through the nine anchors.

5. preview and program are resolved, never assumed

They are not buffers. They are names for whichever of the device’s three preset buffers is pending or live right now, and a take swaps them — differently on different screens of the same device.

Over UDP, live layer parameters must name a buffer —/a, /b or /c. Resolving preview orprogram needs the switcher’s current take state, which the listener does not hold, so it refuses those addresses with that reason rather than guessing. A layer move landing in whichever buffer happened to be live is exactly the failure this rule exists to prevent. Typed at the tool’s own console it works, because the page has the device’s state.

Not implemented, and reserved

There is no relative form. A relative step needs to know the current value, which makes it a property of the surface holding the encoder rather than of the address space — duplicating a control surface’s soft-pickup logic in an address would give two implementations of one idea. /rel is refused by name, so the reserved tail explains itself instead of looking like a typo.

Argument types

Numbers arrive as int32, int64, float32 or float64 and are all read as numbers. Strings carry enum values by name — LIVE_3 — matched case-insensitively; an enum may also be given as an integer index, because a button on a surface has nowhere to put a name, and an index is bounds-checked. A value the device does not have is refused rather than rounded to the nearest one.T/F are true and false, and an impulse is read as a press.

Bundles are unpacked and their contents run. Timetags are ignored: holding a video cue until a clock this machine does not share says so would make it fire late because two computers disagree about the time, which is worse than firing it now.

Nothing is ever sent back. This listens; it does not answer.

Every address

{n}, {slot}, {l} and {out} are placeholders; their ranges are in the description. A layer is numbered, or NATIVE.

Where these came from

The memory, take and multiviewer addresses are verified against LivePremier firmware6.2.73. The layer and screen-group parameters —67 and 19 of them — come from a switcher’s own Web RCS bundle, read off a NLC_CMAX, so every range above is the device’s statement about itself rather than a number copied out of a PDF.

This table is generated from the implementation, not transcribed: it is the output of the same call the tool’s console resolves an address with. Regenerate the parameter catalogue against different firmware and the dictionary follows, with nobody editing prose. Copied from livepremier-plus at 948b951a79f2.

The listener is off by default, binds to loopback unless told otherwise, and writes to the switcher over AWJ on TCP 10606 — so it works with no browser open, which is the point of a show-control input. That port can be disabled in the switcher’s own Web RCS security settings; when it is, every message fails with the same connection error.