fix(viewer): make recorded layers deterministic

apps/control-station/src/components/RerunViewport.tsx

@@ -49,6 +49,7 @@ export interface RerunViewportProps {
   presentationGate?: RecordedAdmissionPhase;
   expectedTimelineStartSeconds?: number;
   expectedTimelineEndSeconds?: number;
+  initialPlaybackStartSeconds?: number;
   onStatusChange?: (status: RerunViewportStatus, message?: string) => void;
   onSelectionChange?: (selection: RerunSelection | null) => void;
   onPlaybackChange?: (state: RerunPlaybackState | null) => void;
@@ -295,12 +296,21 @@ export function createRecordedAutoplayGate(): {
     rangeNs: { min: number; max: number } | null,
     seekToStart: (startNs: number) => void,
     startPlaying: () => void,
+    preferredStartNs?: number,
   ) => boolean;
   attempted: () => boolean;
 } {
   let consumed = false;
   return {
-    attempt(viewerStarted, fullyBuffered, presentationReady, rangeNs, seekToStart, startPlaying) {
+    attempt(
+      viewerStarted,
+      fullyBuffered,
+      presentationReady,
+      rangeNs,
+      seekToStart,
+      startPlaying,
+      preferredStartNs,
+    ) {
       if (
         consumed ||
         !viewerStarted ||
@@ -309,8 +319,11 @@ export function createRecordedAutoplayGate(): {
         !isUsableRecordedPlaybackRange(rangeNs)
       ) return false;
       consumed = true;
+      const startNs = Number.isFinite(preferredStartNs)
+        ? Math.min(Math.max(preferredStartNs as number, rangeNs.min), rangeNs.max)
+        : rangeNs.min;
       return attemptRecordedAutoplay(
-        () => seekToStart(rangeNs.min),
+        () => seekToStart(startNs),
         startPlaying,
       );
     },
@@ -515,7 +528,8 @@ export async function fetchRecordedBlueprintRrd(
       custom_color: settings.customColor,
       active_view: activeView,
       view_reset_generation: viewResetGeneration,
-      unified_perception: perceptionLayers.enabled,
+      unified_perception:
+        perceptionLayers.detections2d || perceptionLayers.segmentation,
       show_detections_2d: perceptionLayers.detections2d,
       show_segmentation: perceptionLayers.segmentation,
       show_cuboids_3d: perceptionLayers.cuboids3d,
@@ -616,6 +630,7 @@ export function RerunViewport({
   presentationGate = "ready",
   expectedTimelineStartSeconds,
   expectedTimelineEndSeconds,
+  initialPlaybackStartSeconds,
   onStatusChange,
   onSelectionChange,
   onPlaybackChange,
@@ -982,6 +997,9 @@ export function RerunViewport({
                   () => {
                     viewer.set_playing(event.recording_id, true);
                   },
+                  initialPlaybackStartSeconds === undefined
+                    ? undefined
+                    : initialPlaybackStartSeconds * 1_000_000_000,
                 );
                 if (autoplayStarted) {
                   playing = true;
@@ -1153,6 +1171,7 @@ export function RerunViewport({
     expectedTimelineEndSeconds,
     expectedTimelineStartSeconds,
     followLive,
+    initialPlaybackStartSeconds,
     onPlaybackChange,
     onPlaybackControllerChange,
     onSelectionChange,

apps/control-station/src/workspaces/Workspaces.tsx

@@ -336,10 +336,13 @@ function SpatialWorkspace({
     (source) => source.capabilities.overlay && source.modality !== "point-cloud",
   );
   const recordedPerceptionSupported = recordedSource && perceptionAvailability !== "unavailable";
-  // Keep one stable original-video + world composition for every admitted
-  // perception recording. Layer buttons then only change entity visibility;
-  // they never reparent the 3D view or invalidate the operator's camera.
-  const unifiedPerception = recordedPerceptionSupported;
+  const recordedPerceptionEnabled =
+    showDetections2d || showSegmentation || showCuboids3d;
+  // The native recorded camera remains the authoritative original. Only 2D
+  // image-space overlays need Rerun's paired camera/world composition; 3D
+  // cuboids are added directly to the stable spatial view.
+  const unifiedPerception = recordedPerceptionSupported &&
+    (showDetections2d || showSegmentation);
   const livePerceptionAvailable = !recordedSource && streamActive;
   const detections2dActive = recordedSource
     ? showDetections2d
@@ -354,6 +357,16 @@ function SpatialWorkspace({
     observationLayout.visibleSourceIds.has(source.id) &&
     !source.id.startsWith("recorded.perception."),
   );
+  const initialRecordedPlaybackStartSeconds = recordedSource
+    ? mediaSources.reduce<number | undefined>((earliest, source) => {
+        if (
+          source.id.startsWith("recorded.perception.") ||
+          source.delivery?.kind !== "recorded-fmp4-manifest"
+        ) return earliest;
+        const start = source.delivery.timelineStartSeconds;
+        return earliest === undefined ? start : Math.min(earliest, start);
+      }, undefined)
+    : undefined;
   const presentedMediaSourceCount = unifiedPerception ? 0 : visibleMediaSources.length;
   const pointCloudFocused = Boolean(
     pointCloudSource && observationLayout.focusedSourceId === pointCloudSource.id,
@@ -574,10 +587,11 @@ function SpatialWorkspace({
               expectedTimelineEndSeconds={recordedSource
                 ? state?.observationTimeline?.range?.endSeconds
                 : undefined}
+              initialPlaybackStartSeconds={initialRecordedPlaybackStartSeconds}
               sceneSettings={sceneSettings}
               recordedViewResetGeneration={recordedViewResetGeneration}
               recordedPerceptionLayers={{
-                enabled: unifiedPerception,
+                enabled: recordedPerceptionSupported && recordedPerceptionEnabled,
                 detections2d: showDetections2d,
                 segmentation: showSegmentation,
                 cuboids3d: showCuboids3d,