Lower thirds

A lower third names someone on screen: a name, and under it an optional line (a role, a place, a time): "MAYA OKAFOR / Night shift, St. Jude's". It sits in the picture's lower third, inside the title-safe area, over a shot for a few seconds, and comes in and goes out with a short animation. It is the last open part of the October product audit's finding 19 ("Titles and type": typefaces and the tool's credit line are done).

Read with docs/design/m7-titles.md (title cards, the screenplay's words on screen), docs/design/m4-director.md ("Screenplay directions") and docs/design/m14-immersive-editors.md ("Adding on the timeline").

What exists

Words over the picture (TitleCue, EpisodeIR 1.44; a Timeline title card of kind super): one centered line of the body font, ringed and shadowed, from SUPER:, TITLE:, CHYRON: and LOWER THIRD: in the screenplay. It has no name and line, no design and no animation but a fade, and nothing in Studio or the tools can add, move or change one.
Title colors (titleColors): background, ink and accent from the style's palette.
Typefaces: typography.display and body, bundled or the show's own (StyleSpec 1.1).

The design

What a lower third looks like

Three designs, each drawn in the show's look: the style's title colors (titleColors: the title_background, title_ink and title_accent slots, else the derived ones), the name in its display face and the line in its body face.

Design	Drawn as	In and out
`bar`	a panel of the background color (88% opaque) with an accent stripe on its leading edge; the name in ink, the line in the accent	the panel wipes out from the stripe, the words follow it in
`plain`	the words alone, ringed and shadowed in the background color, as words over the picture are; the line in ink	the words rise a little into place as they fade up
`box`	a card of the background color with an accent border of the style's line weight; the name in ink, the line in the accent	the card slides in from its side as it fades up

Sizes are for a 1080-line frame and scale with the output: the name 46 px, the line 32 px, times the style's scale. The name is in capitals unless the style says not. It stands on the left of the title-safe area (or the right), its foot at 85% of the frame's height; a name or a line too wide for 60% of the frame shrinks to fit. The animation lasts the style's inSec (0.4 s by default) at each end, at most a third of the lower third; 0 cuts it in and out. Everything is a function of the frame number, so any frame draws alone.

How a style chooses (StyleSpec 1.2)

typography.lowerThird, all optional: design (bar, plain or box; bar when left out), side (left or right), caps (the name in capitals, true), scale (0.75 to 1.5) and inSec (0 to 1). A style that says nothing draws a bar on the left. The core resolves these into the Timeline, so the engine only paints.

The data

EpisodeIR 1.53. A lower_third cue among a scene's cues:

{ "type": "lower_third", "id": "n01", "name": "Maya Okafor", "line": "Night shift, St. Jude's",
  "character": "char.maya", "shot": "sh020", "offsetSec": 0.5, "durationSec": 4 }

name (1 to 60 characters) and line (up to 80) are what it says; character whom it names, when it is one of the cast. design and side override the style's for this one.
On a shot: shot (with offsetSec, 0 to 30, default 0.5) puts it over that shot, from that long after the cut into it. A re-cut moves it with the shot, and it ends by the cut out of it, its animation played before the cut.
On the scene: without shot, at times it as any cue (after, with or at a time).
durationSec (1 to 20, default 4) is how long it shows, its animation included. It never holds up the cues after it and never makes a scene longer: it ends with its scene at the latest. Nothing can be timed from a lower third on a shot.

Timeline 1.30. lowerThirds: each with its scene and cue (for edits), startFrame, endFrame, inFrames, outFrames, design, side, caps, scale, name, line, and the background, ink and accent it is drawn in. A Timeline without lower thirds keeps its bytes and its version.

ShowManifest. introduceCharacters: true (Show settings › Format › "Introduce characters with a lower third"). Like toolCredit it is a setting, not a feature a reader must know, so show.json stays 1.0.

The engine

The player finds the lower thirds playing at the frame, one a side (of two on a side, the one that started later), and draws them in the shot views' own 2D canvas over the stage, as words over the picture are, so the post pass (grade, grain, paper) is on them too. A view that has never shown one builds nothing for it, so every other frame keeps its pixels. Studio's previs (the host's own camera) shows the shot alone, without them.

The screenplay

directions.ts reads words on screen. What screenwriters mean:

SUPER: MAYA OKAFOR, NIGHT SHIFT names someone: when the words before the first comma, dash or slash are a character of the cast (by any name the cast answers to), it is a lower third for them, the rest its line. CHYRON: and LOWER THIRD: are always lower thirds, the name and line split the same way.
SUPER: CORAL CITY, 1952, TITLE:, TITLE OVER:, SUPERIMPOSE: are words over the picture, as before.
TITLE CARD:, CARD:, and now TITLE OVER BLACK:, SUPER OVER BLACK: and OVER BLACK:, are a full card in the picture's place.

The directors

Both directors, without a model, place lower thirds from the episode's final cut:

A screenplay's lower third for a character goes over the first shot that shows them (Timeline subjects) from where it is written on, half a second after its cut; one for no character, or someone never shown after it, stays where it is written, with the cue after it.
With introduceCharacters, each of the cast gets one where the episode first shows them, unless the screenplay names them first: over their first single (them alone) of at least 2.5 s in the scene they first appear in, since the establishing wide that first shows them shows them small or from behind; else the first shot that shows them that long, else their first. It says their name, and the first clause of their persona's role as the line ("Chief engineer of the Marigold").
Two on one shot take turns when the shot has room (the second after the first, a quarter of a second between), else stand on either side at once.

The model director's prompts, context and tools do not change (lower thirds are the code's, as the screenplay's words on screen are), so its fixtures keep their keys.

Editing

edit_episode gains set_lower_third: with cue naming one, change its name, line, character, design (style takes the cue's own away), side, durationSec, or move it to a shot and offsetSec, or onto the performance with after or with (and offsetSec); remove deletes it. Otherwise a new one (id cue, else the next free nNN) needs a shot, or after or with, and a name or a character (whose full name it then takes, and whose role the line, when no line is given). set_timing moves one on a shot along its shot and sets its length.

Studio

The Overlays row on the timeline, under Captions: each lower third a block, labelled with its name and line. Drag it in time (it moves to the shot it is dropped on), drag its end to change its length, Delete removes it, comma and period nudge it.
Adding: A then W ("who") at the playhead, or "Lower third" in the Add menu (and on the Overlays row's right-click). It goes over the shot at the playhead, from there; its name is the shot's one subject's, when it frames one person (with their role as its line), else "Name", ready to type over in the inspector.
The inspector: the name, the line, the design (the style's, a bar, plain words, a boxed card), the side, when it starts after its cut and how long it lasts, and Delete.
Show settings › Format: "Introduce characters with a lower third".

The installed app and the browser run the same GDScript and the same player, so they draw it alike, frame for frame.

Not in this

Lower thirds that carry a logo or a picture.
A lower third over a title card.
Introducing a character only in the first episode they appear in (the show's memory knows).