filmcraft/docs/captions.md

Captions

FilmCraft keeps captions on caption tracks in the sequence, shown in their own area above the video tracks (as Premiere does). Caption tracks are saved in the .fcproj (project format version 2; version 1 projects open with no caption tracks).

Model

• Caption track (CaptionTrack, crates/project/src/caption.rs): name, format (Subtitle, CEA-608, CEA-708, Teletext), language, output eye (shown in the Program monitor and burned in on export), lock, sync lock, and a track style: font family and font style (fontStyle, default SemiBold, resolved like graphic text: the nearest weight when the family has no face of that name), font size (pixels at 1080 lines, scaled to the frame), text colour, background box and its colour, outline width and colour, alignment (left/centre/right), position (top/middle/bottom) and margin (a fraction of the frame height, default 0.08; captions.setStyle clamps it to 0–0.45), line spacing.
• Caption: in/out in exact Ticks, text (lines separated by \n; <i>, <b>, <u> kept as written), optional speaker, and the WebVTT cue id and cue settings, kept for round trips. Captions on a track never overlap.

Files

Format	Import	Export	Notes
SubRip .srt	✓	✓	Forgiving reader (BOM, UTF-16, Windows-1252, CRLF, missing indexes, ,/. ms, missing hours).
WebVTT .vtt	✓	✓	Keeps cue ids, cue settings, <v Speaker>, STYLE/REGION/NOTE blocks. line:N% and align: are honoured when drawing.
Scenarist SCC .scc	✓	✓	CEA-608 at 29.97 fps. Reads pop-on, roll-up and paint-on; writes pop-on with drop-frame (default) or non-drop timecode.

File ▸ Import (or dropping a file) recognises caption files by extension and content and adds a new caption track to the open sequence (a sequence is created when none is open). Cue times are snapped to the sequence's frames. File ▸ Export ▸ Captions… (and Export captions… in the Text panel) opens Caption Export Settings: pick the File Format (SRT, WebVTT, SCC, MCC, EBU STL, TTML or DFXP; the last choice is offered next time), then the file name in a save panel that offers only that format. A name typed with another caption format's extension (subs.srt with WebVTT chosen) is written in that format, since that is the file the save panel asked about; any other name gets the chosen format's extension (subs becomes subs.vtt). If a file with that new name already exists, nothing is exported, because the save panel only asked about replacing the name as typed. For example, with WebVTT chosen, typing keep when keep.vtt already exists leaves keep.vtt untouched and the status line says so; choosing keep.vtt itself in the save panel, which then asks before replacing it, replaces it. Given a path (agents, the CLI), captions.export takes the format from format or from the file extension.

Details of each format and the SCC encoder are in crates/captions/README.md.

Editing

Command	Menu / shortcut	Params
captions.newTrack	Sequence ▸ Captions ▸ Add New Caption Track… (⌥⌘A)	format, name, language
captions.add	Sequence ▸ Captions ▸ Add Caption at Playhead (⌥⌘C)	track, text, time, durationSeconds (3)
captions.next / captions.previous	Sequence ▸ Captions ▸ Go to Next/Previous Caption Segment (⌥⌘↓/↑)
captions.showAll / captions.hideAll	Sequence ▸ Captions
captions.split	Text panel ✂; Razor tool on a caption (⇧: every caption track)	caption, time (default: every caption under the playhead)
captions.merge	Text panel	captions (consecutive, one track)
captions.setText	Text panel text field	caption, text, speaker
captions.setTimes	Text panel in/out fields	caption, start…/end… (Time ticks, Frame, Seconds, Timecode)
captions.trim	drag a caption edge in the timeline	caption, edge (in/out), delta or deltaFrames
captions.move	drag a caption in the timeline	captions, delta or deltaFrames
captions.duplicate	⌥-drag a caption in the timeline	captions, delta or deltaFrames — copies on the same tracks, overwriting what is there
captions.delete	Edit ▸ Clear / Ripple Delete with captions selected	captions, ripple
edit.copy / edit.cut / edit.paste / edit.pasteInsert	⌘C / ⌘X / ⌘V / ⇧⌘V with only captions selected	captions paste at the playhead on the tracks they came from, overwriting (Paste Insert pushes later captions on); Paste places whichever of clips or captions was copied last
captions.select, captions.goTo	click / number button	captions, add / caption
captions.setTrack	caption track header (eye, lock)	track, name, format, language, enabled, locked, syncLock
captions.setStyle	Text panel style strip	track, font, fontStyle, size, color, background, backgroundColor, outline, outlineColor, align, anchor, margin, lineSpacing, reset
captions.deleteTrack		track
captions.import / captions.export	File ▸ Export ▸ Captions…	path, format, track, dropFrame
captions.list	(query)	track — tracks, styles and captions with timecodes (a track that names no caption track is an error)

Tracks are addressed by id or "C1", "C2"… (top first). Edits are limited by neighbouring captions and a one-frame minimum. Sync-locked caption tracks follow insert and extract edits on the media tracks (a caption across an insert point is split). Add Edit to All Tracks (⇧⌘K) also splits captions.

Timeline and Text panel

• Caption rows: header with C1… badge, lock, output eye, name and format; caption blocks in violet showing their text (Arabic and Hebrew in reading order from the block's right edge). Click selects (⌘/⇧ adds), drag moves (the whole selection; ⌥-drag copies), edge drag trims, the Razor tool cuts, double-click opens the Text panel. Automation ids: timeline.caption.<id>, timeline.captionTrack.C1[.locked|.enabled].
• Text panel ▸ Captions: search, track picker (also creates tracks of each format), add / split / merge / delete / export buttons, the list of segments with editable in/out timecodes and text (committed when the field loses focus; Arabic and Hebrew show in reading order and are edited in logical order while the field has focus), and the track style strip (font, font style, size, colour, box, alignment, position). The list keeps the caption under the playhead in view (centred as the playhead reaches it, not while a field is being edited). Automation ids: text.tab.Captions, text.captions.add|split|merge|delete|export|search|track, text.captions.<id>.in|out|text|goto|row, text.captions.style.*.

Burn-in

The Program monitor shows the visible caption tracks. On export, file.exportMedia {"burnCaptions": true} (Export mode: Burn Captions Into Video) draws them into every frame. Captions are set in the track's font and font style (Inter SemiBold by default, OFL, bundled) by the text engine (crates/text: shaping, kerning, bidi); italics/bold markup is not yet drawn differently. The captions of a nested sequence are part of the nest's picture: they are drawn wherever the nest is shown, in the Program monitor and in every export, whether or not the outer sequence shows or burns in its own.