diff --git a/src/components/video-editor/AnnotationOverlay.tsx b/src/components/video-editor/AnnotationOverlay.tsx
index abbdf43f..4bdd44ec 100644
--- a/src/components/video-editor/AnnotationOverlay.tsx
+++ b/src/components/video-editor/AnnotationOverlay.tsx
@@ -40,6 +40,7 @@ function clampPercent(value: number) {
 	return Math.min(100, Math.max(0, value));
 }
 
+/** Render an annotation in preview space with editor drag and resize controls. */
 export function AnnotationOverlay({
 	annotation,
 	isSelected,
diff --git a/src/components/video-editor/VideoPlayback.tsx b/src/components/video-editor/VideoPlayback.tsx
index 07727ec8..af8b49db 100644
--- a/src/components/video-editor/VideoPlayback.tsx
+++ b/src/components/video-editor/VideoPlayback.tsx
@@ -1252,6 +1252,9 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 
 		useEffect(() => {
 			zoomRegionsRef.current = zoomRegions;
+			if (!isPlayingRef.current) {
+				shouldSnapPausedFrameRef.current = true;
+			}
 		}, [zoomRegions]);
 
 		useEffect(() => {
diff --git a/src/components/video-editor/videoPlayback/videoEventHandlers.ts b/src/components/video-editor/videoPlayback/videoEventHandlers.ts
index c0c98000..4b6be5d2 100644
--- a/src/components/video-editor/videoPlayback/videoEventHandlers.ts
+++ b/src/components/video-editor/videoPlayback/videoEventHandlers.ts
@@ -27,6 +27,10 @@ interface VideoEventHandlersParams {
 	speedRegionsRef: React.MutableRefObject<SpeedRegion[]>;
 }
 
+/**
+ * Bind media events to the preview's presented-frame clock while honoring trim
+ * and speed regions.
+ */
 export function createVideoEventHandlers(params: VideoEventHandlersParams) {
 	const {
 		video,
diff --git a/src/lib/exporter/captionRenderer.ts b/src/lib/exporter/captionRenderer.ts
index 25846c30..03794acd 100644
--- a/src/lib/exporter/captionRenderer.ts
+++ b/src/lib/exporter/captionRenderer.ts
@@ -15,6 +15,7 @@ import {
 } from "@/components/video-editor/types";
 import { drawSquircleOnCanvas } from "@/lib/geometry/squircle";
 
+/** Draw the active caption using the same typography and timing as preview. */
 export function renderCaptions(
 	ctx: CanvasRenderingContext2D,
 	cues: CaptionCue[],
diff --git a/src/lib/exporter/frameRenderer.ts b/src/lib/exporter/frameRenderer.ts
index 7217c20a..473071d0 100644
--- a/src/lib/exporter/frameRenderer.ts
+++ b/src/lib/exporter/frameRenderer.ts
@@ -1661,6 +1661,7 @@ export class FrameRenderer {
 		};
 	}
 
+	/** Advance the export camera from the shared scene target at this media time. */
 	private updateAnimationState(timeMs: number): number {
 		if (!this.cameraContainer || !this.layoutCache) return 0;
 
diff --git a/src/lib/exporter/modernFrameRenderer.ts b/src/lib/exporter/modernFrameRenderer.ts
index 53f37b4e..25dc33c3 100644
--- a/src/lib/exporter/modernFrameRenderer.ts
+++ b/src/lib/exporter/modernFrameRenderer.ts
@@ -3343,6 +3343,7 @@ export class FrameRenderer {
 		}
 	}
 
+	/** Advance the export camera from the shared scene target at this media time. */
 	private updateAnimationState(timeMs: number): number {
 		if (!this.cameraContainer || !this.layoutCache) {
 			return 0;
diff --git a/src/lib/exporter/modernVideoExporter.ts b/src/lib/exporter/modernVideoExporter.ts
index be3889d8..b14c11a5 100644
--- a/src/lib/exporter/modernVideoExporter.ts
+++ b/src/lib/exporter/modernVideoExporter.ts
@@ -2096,6 +2096,7 @@ export class ModernVideoExporter {
 		);
 	}
 
+	/** Build deterministic per-frame camera transforms for native compositors. */
 	private getNativeStaticLayoutZoomTelemetry(
 		layout: ReturnType<typeof computePaddedLayout>,
 		totalFrames: number,