liminal-hq · ScottMorris · Apr 4, 2026 · Apr 3, 2026 · Apr 3, 2026 · Apr 3, 2026
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/README.md b/README.md
@@ -16,7 +16,7 @@ Current DVD authoring capabilities include:
 - authored menu routing for VMGM, titleset, and title-return paths, including keyboard-safe entry selection
 - asset inspection with embedded metadata title surfacing, compatibility explanations, and fix-oriented validation
 - DVD build planning and execution with diagnostics export and toolchain checks
-- bitmap subtitle muxing, plus a developer option to skip unsupported text subtitle mappings during builds
+- bitmap subtitle muxing plus first-pass text subtitle rendering for DVD authoring
 
 ## Workspace layout
 
@@ -52,7 +52,7 @@ If Rust tooling is not installed locally, run Rust and Tauri commands through `g
 Current app behaviour also includes:
 
 - a persistent thumbnail cache stored in the app cache directory, with Settings controls to inspect and clear cached previews
-- developer toggles to prefer host `PATH` tools over bundled sidecars and to skip unsupported subtitle mappings during builds
+- developer toggles to prefer host `PATH` tools over bundled sidecars and to skip unsupported subtitle mappings during builds, mainly for unknown subtitle types or debugging
 - diagnostics bundle export including toolchain status, build logs, validation issues, project summary, and active developer options
 
 Build the frontend bundle:

diff --git a/SPEC.md b/SPEC.md
@@ -1181,6 +1181,7 @@ Because this app orchestrates binaries, the product should clearly communicate:
 - direct titleset editing with compatibility guidance
 - reversible subtitle track selection
 - bitmap subtitle authoring and muxing
+- first-pass text subtitle rendering and DVD-safe conversion with simplified styling
 - `VIDEO_TS` export
 - optional ISO generation
 - build logs and diagnostics
@@ -1197,7 +1198,6 @@ Because this app orchestrates binaries, the product should clearly communicate:
 - motion menus
 - autogenerated title, chapter, audio, and subtitle menu creation
 - menu themes and theme-aware generation
-- text subtitle rendering and conversion
 - advanced VM command logic exposure
 - deep program/cell editing
 - Blu-ray authoring

diff --git a/apps/spindle/src/pages/BuildPage.tsx b/apps/spindle/src/pages/BuildPage.tsx
@@ -363,6 +363,8 @@ function getJobIcon(job: BuildJob): string {
 			return '\u{1F517}';
 		case 'extractSubtitles':
 			return '\u{1F4DD}';
+		case 'renderTextSubtitles':
+			return '\u{1F5E8}';
 		case 'authorDvd':
 			return '\u{1F4BF}';
 		case 'createIso':

diff --git a/apps/spindle/src/types/project.ts b/apps/spindle/src/types/project.ts
@@ -306,6 +306,7 @@ export interface BuildSettings {
 	generateIso: boolean;
 	safetyMarginBytes: number;
 	allocationStrategy: AllocationStrategy;
+	subtitleRenderMode?: 'one-pass' | 'two-pass';
 }
 
 // ── Validation ──────────────────────────────────────────────────────────────
@@ -390,6 +391,22 @@ export type BuildJob =
 			command: string[];
 			label: string;
 	  }
+	| {
+			type: 'renderTextSubtitles';
+			titleId: string;
+			titleName: string;
+			sourcePath: string;
+			sourceStreamIndex: number;
+			inputPath: string;
+			outputPath: string;
+			subtitlePath: string;
+			prepareCommand: string[];
+			spumuxXml: string;
+			command: string[];
+			label: string;
+			renderMode: 'one-pass' | 'two-pass';
+			fontFamily: string;
+	  }
 	| {
 			type: 'authorDvd';
 			xmlPath: string;

diff --git a/docs/core-dvd-authoring-completion.md b/docs/core-dvd-authoring-completion.md
@@ -53,13 +53,13 @@ When all source streams are already mapped, the picker is disabled. The subtitle
 
 ### 4. Subtitle Authoring and Export Pipeline
 
-**Build planner** — `planner.rs` generates `ExtractSubtitles` jobs for each title with bitmap subtitle mappings. Only bitmap subtitles (`dvd_subtitle`, `dvdsub`, `hdmv_pgs_subtitle`, `pgssub`) are extracted; text subtitle rendering is out of scope.
+**Build planner** — `planner.rs` muxes bitmap subtitle mappings during `TranscodeTitle`. Text subtitle mappings generate explicit `RenderTextSubtitles` jobs that first normalise the source stream to SRT, then compose DVD subtitle streams onto the authored title MPEG with `spumux` text rendering.
 
-**FFmpeg extraction** — `ffmpeg.rs` provides `build_ffmpeg_subtitle_extract_command()` which generates: `ffmpeg -i source -map 0:{index} -c:s dvd_subtitle output.sub`
+**Rendering path** — `ffmpeg.rs` provides a text-subtitle preparation command that exports supported text subtitle streams to SRT. `spumux` then renders that text into DVD subpictures using a host font and DVD-safe defaults.
 
-**dvdauthor XML** — `authoring.rs` generates `<subpicture>` declarations with language attributes for each title's subtitle mappings within the titleset's `<titles>` section.
+**dvdauthor XML** — `authoring.rs` generates `<subpicture>` declarations with language attributes for each title's subtitle mappings within the titleset's `<titles>` section. The first-pass text subtitle path keeps that seam by producing a final title MPEG that already contains the rendered subtitle streams.
 
-**Build job type** — `ExtractSubtitles` variant added to `BuildJob` enum in `types.rs`, with title_id, title_name, source_path, output_path, command, and label fields. The frontend `BuildJob` union and `BuildPage.tsx` handle this job type for progress display.
+**Build job types** — `TranscodeTitle` remains the bitmap subtitle mux point, and `RenderTextSubtitles` adds the explicit text subtitle rendering stage surfaced on the Build page.
 
 ---
 
@@ -117,28 +117,28 @@ All fields use `#[serde(default)]` for backwards compatibility with existing pro
 
 **Fix descriptions by rule:**
 
-| Code                             | Suggested fix                                                                                                                  |
-| -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
-| `disc.no-titlesets`              | Add at least one titleset to the disc.                                                                                         |
-| `disc.no-titles`                 | Add titles in the Titles page to define the disc's playback structure.                                                         |
-| `disc.no-first-play`             | Set a first-play action on the overview page so the disc has a defined startup behaviour.                                      |
-| `title.no-source`                | Open the title and assign a source asset from the Assets library.                                                              |
-| `title.dangling-source`          | Re-import the missing asset or assign a different source.                                                                      |
-| `title.no-video-mapping`         | Select a video stream in the title's track mapping section.                                                                    |
-| `title.no-output-profile`        | Choose a video output profile (resolution and aspect ratio) for this title.                                                    |
-| `chapter.non-increasing`         | Reorder or adjust chapter timestamps so they are strictly increasing.                                                          |
-| `chapter.beyond-duration`        | Move this chapter to a timestamp within the asset's duration or remove it.                                                     |
-| `menu.no-buttons`                | Add at least one button to define user interaction.                                                                            |
-| `menu.no-default-button`         | Set a default button so the player knows which button to highlight on entry.                                                   |
-| `menu.button-no-action`          | Assign an action (play title, show menu, etc.) to this button.                                                                 |
-| `menu.dangling-title-ref`        | Update the button action to point to an existing title or remove it.                                                           |
-| `menu.dangling-menu-ref`         | Update the button action to point to an existing menu or remove it.                                                            |
-| `menu.dangling-nav-ref`          | Remove the broken nav link or use auto-generate navigation to rebuild all links.                                               |
-| `menu.button-no-navigation`      | Use the auto-generate navigation feature to create directional links for all buttons.                                          |
-| `titleset.format-mismatch`       | Ensure all titles in this titleset use the same resolution and aspect ratio, or move mismatched titles to a separate titleset. |
-| `build.no-output-dir`            | Set an output directory in the build settings to avoid being prompted each time.                                               |
-| `subtitle.dangling-stream`       | The source file may have changed. Remove this subtitle mapping or relink the asset.                                            |
-| `subtitle.text-only-unsupported` | Text subtitle rendering is not yet supported. Remove text subtitles or provide bitmap subtitle sources.                        |
+| Code                                 | Suggested fix                                                                                                                  |
+| ------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------ |
+| `disc.no-titlesets`                  | Add at least one titleset to the disc.                                                                                         |
+| `disc.no-titles`                     | Add titles in the Titles page to define the disc's playback structure.                                                         |
+| `disc.no-first-play`                 | Set a first-play action on the overview page so the disc has a defined startup behaviour.                                      |
+| `title.no-source`                    | Open the title and assign a source asset from the Assets library.                                                              |
+| `title.dangling-source`              | Re-import the missing asset or assign a different source.                                                                      |
+| `title.no-video-mapping`             | Select a video stream in the title's track mapping section.                                                                    |
+| `title.no-output-profile`            | Choose a video output profile (resolution and aspect ratio) for this title.                                                    |
+| `chapter.non-increasing`             | Reorder or adjust chapter timestamps so they are strictly increasing.                                                          |
+| `chapter.beyond-duration`            | Move this chapter to a timestamp within the asset's duration or remove it.                                                     |
+| `menu.no-buttons`                    | Add at least one button to define user interaction.                                                                            |
+| `menu.no-default-button`             | Set a default button so the player knows which button to highlight on entry.                                                   |
+| `menu.button-no-action`              | Assign an action (play title, show menu, etc.) to this button.                                                                 |
+| `menu.dangling-title-ref`            | Update the button action to point to an existing title or remove it.                                                           |
+| `menu.dangling-menu-ref`             | Update the button action to point to an existing menu or remove it.                                                            |
+| `menu.dangling-nav-ref`              | Remove the broken nav link or use auto-generate navigation to rebuild all links.                                               |
+| `menu.button-no-navigation`          | Use the auto-generate navigation feature to create directional links for all buttons.                                          |
+| `titleset.format-mismatch`           | Ensure all titles in this titleset use the same resolution and aspect ratio, or move mismatched titles to a separate titleset. |
+| `build.no-output-dir`                | Set an output directory in the build settings to avoid being prompted each time.                                               |
+| `subtitle.dangling-stream`           | The source file may have changed. Remove this subtitle mapping or relink the asset.                                            |
+| `subtitle.text-rendering-simplified` | Text subtitle rendering uses first-pass DVD-safe styling with a host font.                                                     |
 
 **Clickable issue navigation** — Validation issues in OverviewPage and BuildPage are clickable. Clicking an issue navigates to the relevant page (titles, menus, build, etc.) and auto-selects the affected entity using a `NavigationContext` provided by `App.tsx`. Entity type determines the target route:
 

diff --git a/docs/text-subtitle-rendering-plan.md b/docs/text-subtitle-rendering-plan.md
@@ -10,7 +10,13 @@ Enable text-based subtitle streams (SRT, ASS/SSA, WebVTT, `mov_text`) to be rend
 
 ### Current state
 
-The bitmap subtitle path is fully functional: extraction via FFmpeg, muxing via spumux, and `<subpicture>` declarations in dvdauthor XML. Text subtitles are detected during inspection and classified as `SubtitleType::Text`, but the build pipeline filters them out. A `subtitle.text-only-unsupported` validation warning tells users that text subtitles cannot yet be authored.
+The shipped first pass now keeps the current `dvdauthor` seam intact by:
+
+1. transcoding titles to DVD MPEG as before
+2. normalising text subtitle mappings to SRT with FFmpeg
+3. composing rendered DVD subtitle streams onto the authored title MPEG with `spumux` text subtitle rendering
+
+Text subtitles are no longer blocked outright, but the first pass stays honest about simplified styling and host-font dependence.
 
 ### DVD subtitle constraints
 
@@ -38,36 +44,12 @@ From `inspect.rs::classify_subtitle_type`:
 
 ### Rendering approach
 
-Use FFmpeg's subtitle filter chain to render text subtitles into bitmap subpictures. FFmpeg can:
-
-1. Decode all recognised text formats (SRT, ASS, SSA, WebVTT, `mov_text`).
-2. Render styled text onto a transparent canvas via the `subtitles` or `ass` filter.
-3. Output the result as a VOBsub stream (`-c:s dvd_subtitle`).
-
-The rendering pipeline is a two-step process per text subtitle mapping:
+The implemented first pass uses a hybrid seam:
 
-**Step 1 — Render text to bitmap video overlay**
-
-Generate a short video stream where each frame is a transparent canvas with the subtitle text rendered on it. FFmpeg's `subtitles` filter handles this when applied to a blank video input:
-
-```
-ffmpeg -f lavfi -i "color=c=black@0:s=720x480:d={duration}" \
-       -vf "subtitles={source}:si={stream_index}:force_style='{style}'" \
-       -c:v rawvideo -pix_fmt yuva420p \
-       {temp_overlay}.nut
-```
-
-**Step 2 — Convert overlay to VOBsub**
-
-Quantise the rendered overlay to DVD's 4-colour palette and package as VOBsub:
-
-```
-ffmpeg -i {temp_overlay}.nut \
-       -c:s dvd_subtitle \
-       {output}.sub
-```
+1. FFmpeg decodes the mapped text subtitle stream and exports it to SRT.
+2. `spumux` renders that text input into DVD subtitle graphics while multiplexing the subtitle stream into the authored title MPEG.
 
-An alternative single-pass approach may be viable depending on FFmpeg version capabilities. The two-step approach is safer and allows intermediate inspection.
+This keeps the current authoring path compatible with `dvdauthor` and avoids relying on a direct FFmpeg text-to-`dvd_subtitle` path that is not available in the current toolchain.
 
 ### Style defaults
 

diff --git a/plugins/tauri-plugin-spindle-project/Cargo.toml b/plugins/tauri-plugin-spindle-project/Cargo.toml
@@ -15,6 +15,7 @@ serde_json = "1"
 thiserror = "2"
 uuid = { version = "1", features = ["v4", "serde"] }
 chrono = { version = "0.4", features = ["serde"] }
+isolang = "2.4"
 
 [build-dependencies]
 tauri-plugin = { version = "2", features = ["build"] }