Merge Ψ-W2-T2: a bit-identical capture collapses to one lossless mono channel

# Conflicts: # src/shell/capture/CLAUDE.md # src/shell/capture/capture.cpp # src/shell/capture/capture.h
2026-08-01 22:23:06 -04:00
parent 91f3ffb09e 8b191e3379
commit 6e6f4a6a15
14 changed files with 444 additions and 22 deletions
@@ -51,7 +51,7 @@ detail not covered there:

 ## Modules

- `capture` — two CONCRETE backends with deliberately different lifecycles (no shared interface — the former `ICaptureBackend` was deleted in Q-W3, T4-26: one deriver, zero polymorphic call sites): `OfflineRenderBackend` (deterministic default, synchronous) and `RealtimeRecordBackend` (async begin/tick/abort). Input: `CaptureRequest`. Output: finished file + populated `Sample` handed to `bank_model`.
+- `capture` — two CONCRETE backends with deliberately different lifecycles (no shared interface — the former `ICaptureBackend` was deleted in Q-W3, T4-26: one deriver, zero polymorphic call sites): `OfflineRenderBackend` (deterministic default, synchronous) and `RealtimeRecordBackend` (async begin/tick/abort). Input: `CaptureRequest`. Output: finished file + populated `Sample` handed to `bank_model`. It also owns the two file-side steps both backends share, in this order: `collapseCapturedFileToMono` (the lossless mono collapse, applied to the landed file) and `stampCaptureSample`, which measures the channel count off that same file so the entry and the audio cannot disagree. And `captureNameFor` — the impure local-clock read the entry points call to build a request's label + stem, kept out of the pure `core/capture/capture_name` composition it feeds.
 - `scope_resolve` (`shell/capture`) — scope/source resolution shared by every capture entry point (Q-W3 hoist out of `main.cpp`): razor-else-time range inference, selected-track/selected-item-owning-track collection with canonical GUIDs, and the M10 provenance-assembly inputs (read BEFORE the FX-bypass guard neutralizes the in-scope chain). Also the one place a source track's NAME is read (`trackName`, via `GetTrackName` — chosen over `P_NAME` because it already answers REAPER's `"Track N"` convention for an unnamed track), landed on `ResolvedSource::trackNames` parallel to `sourceTracks` and composed into the capture's label + stem by the pure `core/capture/capture_name`.
 - `render_selection` (`shell/capture`) — the transient track selection a selected-tracks render (`&128`) requires, as a stack RAII guard: REAPER prints whatever tracks are selected, so `renderOffline` makes the request's own tracks BE the selection for the render's duration and restores the user's set on every exit path. Engaged ONLY for that source mode, which leaves a stated residual: a `&32` selected-items render still prints whatever ITEMS the user has selected. Live captures are unaffected (that selection is the source), but a recipe replay of a `SelectedItems` capture renders against whatever happens to be selected then — the recipe stores tracks and a range, never item GUIDs, so this guard cannot close it. Filed in `docs/TODO.md`.
 - `render_isolation` (`shell/capture`) — the transient upstream silencing a ranged ITEM render needs, as a stack RAII guard alongside the two above: the selected-tracks source prints everything flowing INTO the track, so each direct folder child's `B_MAINSEND` and each of the track's receives' `B_MUTE` are cut for the render and restored on every exit path. Direct children only — a grandchild reaches the track through the child that owns it. The child-set walk is pure (`core/capture/track_topology`).
@@ -61,7 +61,7 @@ detail not covered there:
 - `realtime_lifecycle` (`shell/capture`) — the in-flight realtime-capture state machine + globals (Q-W3 hoist): the action starts it, `OnTimer` drives it per tick via `DriveRealtimeCapture` (a single-pointer-test idle fast path — load-bearing hot-path guardrail), `CommitRealtimeResult` lands a finished capture in the bank, `AbortRealtimeCaptureForUnload` tears down cleanly on extension unload.
 - `capture_realtime_shell` (`shell/capture`) — the async realtime-record backend surface (Q-W6 split of the former fat `capture.h`): `RealtimeRecordBackend::begin`/`tick`/`abort`, transport-driven across timer ticks (a realtime record cannot block REAPER's UI for its own duration). Deliberately shares NO interface with the offline backend — the lifecycles genuinely differ (the former `ICaptureBackend` interface was deleted in Q-W3, T4-26).
 - `capture_realtime_finalize` (`shell/capture`) — the file-side half of the realtime-record shell (Q-W3, T4-08): discovers the file REAPER actually recorded, moves it into the bank, runs the Auto-tail PCM decay-scan trim, and populates the finished `Sample`.
- `insert` — placement via `InsertMedia`. **Conform-to-project-tempo is an explicit opt-in flag, never silent stretching.**
+- `insert` — placement via `InsertMedia`. **Conform-to-project-tempo is an explicit opt-in flag, never silent stretching.** The mono collapse needs no change here: `insert.cpp` passes only a path to `InsertMedia`, and REAPER derives the item's channel count from the file itself — a 1-channel WAV yields a mono item for free.
 - `provenance_shell` — FX-chain identity queries via `TrackFX_*`/`TakeFX_*` APIs; feeds the pure `provenance` fingerprint builder. Stamps `Sample.provenance` on capture; ambiguous/mixed cases record nothing conservatively.
 - `track_guid` — shared `MediaTrack*` → canonical GUID-string formatter; single source of truth for membership keys.
 - `item_read` — the ONE place a `MediaItem*` is read for its canonical GUID string (`itemGuid`) and for the durable `P_LANENAME` of the fixed lane it sits on (`itemLaneName`); extracted from previously-duplicated `itemGuid`/`itemLaneName` pairs in `view.cpp` and `bank_panel.cpp` — the item-read analog of `track_guid`'s single `MediaTrack*`→GUID-key formatter. Callers must already know the track is fixed-lane (`I_FREEMODE==2`) before calling `itemLaneName`; the pure `isOnManualLane` predicate handles the non-fixed-lane case separately.