docs: the export dialog no longer offers a codec choice

editor-shell.md still described the named destinations under Advanced, which #883 already removed. export-pipeline.md and native-compositor.md now say the dialog always sends h264 while the pipeline still encodes h265 internally, and the manual checklist drops both its destination steps and its H.264/H.265 one.

Author: EtienneLescot

technical-documentation/architecture/editor-shell.md

@@ -60,7 +60,7 @@ of those are local React state, with the document itself read through
 | **Floating inspector** | `src/components/ai-edition/v4/FloatingInspector.tsx` | Floating facet rail over the stage; the open panel either shows the `FacetBody` for the current facet (`effects` / `layout` / `audio` / `cursor` / `captions` / `transcript`) or, when a region is selected, a `SelectionPane` (`:434`) that edits the selected pill by id. The "pencil" rail button opens `EditClipModal` for crop + trim. |
 | **Left chat column** (`ChatStripPanel`) | `src/components/ai-edition/LeftPanel.tsx` | Only mounted when `mode === "edit"` and `chatOpen` is true (`NewEditorShell.tsx` `:1191-1195`). Sends user messages to the LLM via IPC. Resize handle is `v4.chatResizeHandle`; width persists in `localStorage` as `os-editor-chat-width`. |
 | **Modals** | `src/components/ai-edition/Modals.tsx` | `OpenProjectModal`, `NewProjectModal`, `EditClipModal` (per-clip crop + in/out), `UnsavedChangesModal`. Mounted at the shell level (`:1333-1385`) so every trigger site reuses the same instance. |
-| **Export dialog** | `src/components/ai-edition/ExportDialog.tsx` | Named destinations (Web / YouTube, Social, Studio, README GIF) that set format / quality / frame-rate / codec / size together, all of which stay under **Advanced**. Both formats go through the native compositor with the same clip list (`resolveVisibleClips`) and scene (`buildSceneDescription`): `exportGifNative` for GIF, `exportMultiNative` for MP4. |
+| **Export dialog** | `src/components/ai-edition/ExportDialog.tsx` | One settings panel — format (MP4 / GIF), quality, frame rate, and the GIF size and loop controls — with no codec choice and no idle hint plate: every MP4 is H.264. Both formats go through the native compositor with the same clip list (`resolveVisibleClips`) and scene (`buildSceneDescription`): `exportGifNative` for GIF, `exportMultiNative` for MP4. |
 | **Captions pane** | `src/components/ai-edition/CaptionsPane.tsx` | Mounted as a facet body from `FloatingInspector.tsx` (`:1062`). Controls caption appearance + translations; the cues themselves are a derived view over `document.transcripts` (see [`src/lib/ai-edition/captions/`](../../src/lib/ai-edition/captions/)). |
 
 ## Modes and facets

technical-documentation/architecture/export-pipeline.md

@@ -154,9 +154,12 @@ and **one** encoder + muxer pair:
 ## Output formats and codecs
 
 The native MP4 export takes `width`, `height`, `fps`, `codec` and `bitrate` as
-parameters on `exportMulti` and writes H.264 (AMF) by default. The
-user-facing codec choice crosses as the plain `ExportVideoCodec` string
-(`"h264"` / `"h265"` / `"vp9"`) in those params; VP9
+parameters on `exportMulti` and writes H.264 (AMF) by default. The dialog
+always sends `"h264"`: `ExportVideoCodec` still accepts `"h265"`, which the
+pipeline encodes, but nothing offers it any more — H.265 is software-only on
+Linux, slower than software on the measured Macs (see
+[native-compositor.md](native-compositor.md)), and the files are the ones half
+the players cannot open. VP9
 falls back to the same H.264 path on machines without a hardware VP9
 encoder (software VP9 was measured too slow and removed — see
 [native-compositor.md](native-compositor.md#known-gaps)). GIF goes through

technical-documentation/architecture/native-compositor.md

@@ -425,8 +425,10 @@ licence. D3D11VA + AMF survive the LGPL-shared build (verified:
   before the renderer commits. Neither belongs in this PR's diff.
 - **Software VP9 encoding is not supported.** A software VP9 encoder was
   implemented, measured too slow without a hardware VP9 path on the
-  target GPU, and removed. The export pipeline now offers H.264 (AMF) and
-  H.265; VP9 is not a runtime option.
+  target GPU, and removed. The pipeline still encodes H.264 (AMF) and
+  H.265, but the dialog only ever asks for H.264 — see
+  [export-pipeline.md](export-pipeline.md#output-formats-and-codecs). VP9 is
+  not a runtime option.
 - **Live preview is video-only** — `live.rs` does not decode or play audio.
   Editing playback is silent against the exported file; users hear sound
   only when the export runs. Documented in

technical-documentation/testing/manual-e2e-checklist.md

@@ -465,13 +465,10 @@ The agent may only call the fixed tool set in [ai-agent.md](../architecture/ai-a
 The dialog opens on four destinations, each a named set of the settings under *Advanced*, which starts collapsed: Web / YouTube (MP4 1080p, 60 fps), Social (MP4 1080p, 30 fps), Studio (MP4 at Source size, 60 fps), README GIF (GIF Small, 15 fps). All MP4 destinations use H.264.
 
 - [ ] Confirm the top bar's *Export* button is disabled when the project has no asset.
-- [ ] **v2.0.0** — With a loaded project, activate *Export* and confirm the dialog opens on the Destination grid, each destination with its summary line (for example `MP4 · 1920 × 1080 · 60 fps`), and *Web / YouTube* selected.
-- [ ] **v2.0.0** — Pick each destination and confirm it shows as selected and its summary matches what *Advanced* then shows.
-- [ ] **v2.0.0** — Open *Advanced*, set the frame rate to 24, and confirm no destination shows as selected any more.
-- [ ] In *Advanced*, select MP4 and confirm the quality choices are 720p, 1080p, and Source.
-- [ ] Select each MP4 quality and confirm the displayed output dimensions update.
+- [ ] **v2.0.0** — With a loaded project, activate *Export* and confirm the dialog opens on one settings panel: *Format* (MP4 / GIF), *Quality*, *Frame rate*, and no idle hint plate where the progress block will appear.
+- [ ] Confirm the MP4 quality choices are 720p, 1080p, and Source, and that each one updates the displayed output dimensions.
 - [ ] Select 24, 30, and 60 FPS and confirm the selected frame rate remains visible.
-- [ ] Select H.264 and H.265 and confirm the selected codec remains visible.
+- [ ] Confirm there is no codec choice anywhere in the dialog: every MP4 export is H.264.
 - [ ] Select GIF and confirm GIF frame-rate (15, 20, 25, 30 FPS), size (Small, Medium, Large, Original), and *Loop GIF* controls appear.
 - [ ] Change GIF frame rate and size, toggle looping, and confirm the summary reflects the choices.
 - [ ] Start an MP4 export with *Export MP4* and confirm the native rendering progress reports advancing frames or percentage.