4 files changed, 33 insertions, 25 deletions

diff --git a/apps/web/src/timeline/placement/__tests__/resolve.test.ts b/apps/web/src/timeline/placement/__tests__/resolve.test.ts
index ebbfe578..44f0a1fe 100644
--- a/apps/web/src/timeline/placement/__tests__/resolve.test.ts
+++ b/apps/web/src/timeline/placement/__tests__/resolve.test.ts
@@ -14,6 +14,7 @@ import type {
 } from "@/timeline";
 import type { Transform } from "@/rendering";
 import { resolveTrackPlacement } from "@/timeline/placement";
+import { mediaTime, ZERO_MEDIA_TIME } from "@/wasm";
 
 function buildTransform(): Transform {
 	return {
@@ -67,10 +68,10 @@ function buildElement({
 				id,
 				type: "audio",
 				name: id,
-				startTime,
-				duration,
-				trimStart: 0,
-				trimEnd: 0,
+				startTime: mediaTime({ ticks: startTime }),
+				duration: mediaTime({ ticks: duration }),
+				trimStart: ZERO_MEDIA_TIME,
+				trimEnd: ZERO_MEDIA_TIME,
 				volume: 1,
 				sourceType: "upload",
 				mediaId: `media-${id}`,
@@ -80,10 +81,10 @@ function buildElement({
 				id,
 				type: "graphic",
 				name: id,
-				startTime,
-				duration,
-				trimStart: 0,
-				trimEnd: 0,
+				startTime: mediaTime({ ticks: startTime }),
+				duration: mediaTime({ ticks: duration }),
+				trimStart: ZERO_MEDIA_TIME,
+				trimEnd: ZERO_MEDIA_TIME,
 				definitionId: `graphic-${id}`,
 				params: {},
 				transform: buildTransform(),
@@ -94,10 +95,10 @@ function buildElement({
 				id,
 				type: "text",
 				name: id,
-				startTime,
-				duration,
-				trimStart: 0,
-				trimEnd: 0,
+				startTime: mediaTime({ ticks: startTime }),
+				duration: mediaTime({ ticks: duration }),
+				trimStart: ZERO_MEDIA_TIME,
+				trimEnd: ZERO_MEDIA_TIME,
 				content: id,
 				fontSize: 32,
 				fontFamily: "sans-serif",
@@ -118,10 +119,10 @@ function buildElement({
 				id,
 				type: "video",
 				name: id,
-				startTime,
-				duration,
-				trimStart: 0,
-				trimEnd: 0,
+				startTime: mediaTime({ ticks: startTime }),
+				duration: mediaTime({ ticks: duration }),
+				trimStart: ZERO_MEDIA_TIME,
+				trimEnd: ZERO_MEDIA_TIME,
 				mediaId: `media-${id}`,
 				transform: buildTransform(),
 				opacity: 1,
@@ -224,7 +225,11 @@ function buildTimeSpan({
 	duration: number;
 	excludeElementId?: string;
 }) {
-	return { startTime, duration, excludeElementId };
+	return {
+		startTime: mediaTime({ ticks: startTime }),
+		duration: mediaTime({ ticks: duration }),
+		excludeElementId,
+	};
 }
 
 function buildSceneTracks({
diff --git a/apps/web/src/timeline/placement/main-track.ts b/apps/web/src/timeline/placement/main-track.ts
index ab2ab7bd..36632226 100644
--- a/apps/web/src/timeline/placement/main-track.ts
+++ b/apps/web/src/timeline/placement/main-track.ts
@@ -1,4 +1,5 @@
 import type { SceneTracks, TimelineElement, VideoTrack } from "@/timeline";
+import { type MediaTime, ZERO_MEDIA_TIME } from "@/wasm";
 
 export const MAIN_TRACK_NAME = "Main Track";
 
@@ -31,9 +32,9 @@ export function enforceMainTrackStart({
 }: {
 	tracks: SceneTracks;
 	targetTrackId: string;
-	requestedStartTime: number;
+	requestedStartTime: MediaTime;
 	excludeElementId?: string;
-}): number {
+}): MediaTime {
 	if (tracks.main.id !== targetTrackId) {
 		return requestedStartTime;
 	}
@@ -43,11 +44,11 @@ export function enforceMainTrackStart({
 		excludeElementId,
 	});
 	if (!earliestElement) {
-		return 0;
+		return ZERO_MEDIA_TIME;
 	}
 
 	if (requestedStartTime <= earliestElement.startTime) {
-		return 0;
+		return ZERO_MEDIA_TIME;
 	}
 
 	return requestedStartTime;
diff --git a/apps/web/src/timeline/placement/resolve.ts b/apps/web/src/timeline/placement/resolve.ts
index 26275392..680cb0bb 100644
--- a/apps/web/src/timeline/placement/resolve.ts
+++ b/apps/web/src/timeline/placement/resolve.ts
@@ -13,6 +13,7 @@ import type {
 	PlacementSubject,
 	PlacementTimeSpan,
 } from "./types";
+import { ZERO_MEDIA_TIME } from "@/wasm";
 
 type ResolveTrackPlacementParams = PlacementSubject & {
 	tracks: SceneTracks;
@@ -32,7 +33,7 @@ function buildExistingTrackResult({
 	timeSpans: PlacementTimeSpan[];
 }): PlacementResult {
 	const firstSpan = timeSpans[0];
-	const requestedStartTime = firstSpan?.startTime ?? 0;
+	const requestedStartTime = firstSpan?.startTime ?? ZERO_MEDIA_TIME;
 	const adjustedStartTime = enforceMainTrackStart({
 		tracks,
 		targetTrackId: track.id,
diff --git a/apps/web/src/timeline/placement/types.ts b/apps/web/src/timeline/placement/types.ts
index 6847ab36..748f34d7 100644
--- a/apps/web/src/timeline/placement/types.ts
+++ b/apps/web/src/timeline/placement/types.ts
@@ -1,8 +1,9 @@
 import type { ElementType, TrackType } from "@/timeline";
+import type { MediaTime } from "@/wasm";
 
 export interface PlacementTimeSpan {
-	startTime: number;
-	duration: number;
+	startTime: MediaTime;
+	duration: MediaTime;
 	excludeElementId?: string;
 }
 
@@ -29,7 +30,7 @@ export type PlacementResult =
 			trackId: string;
 			trackIndex: number;
 			trackType: TrackType;
-			adjustedStartTime?: number;
+			adjustedStartTime?: MediaTime;
 	  }
 	| {
 			kind: "newTrack";