Merge pull request #433 from meiiie/codex/fix-export-duration-mismatch

fix(export): preserve duration with short video-stream metadata

src/lib/exporter/modernVideoExporter.ts

@@ -15,6 +15,7 @@ import type {
 	ZoomTransitionEasing,
 } from "@/components/video-editor/types";
 import { extensionHost } from "@/lib/extensions";
+import { getEffectiveVideoStreamDurationSeconds } from "@/lib/mediaTiming";
 import { AudioProcessor, isAacAudioEncodingSupported } from "./audioEncoder";
 import { normalizeLightningRuntimePlatform, shouldPreferNativeAutoBackend } from "./backendPolicy";
 import { buildEditedTrackSourceSegments, classifyEditedTrackStrategy } from "./editedTrackStrategy";
@@ -824,7 +825,12 @@ export class ModernVideoExporter {
 		) {
 			const sourceDurationMs = Math.max(
 				0,
-				Math.round((videoInfo.streamDuration ?? videoInfo.duration) * 1000),
+				Math.round(
+					getEffectiveVideoStreamDurationSeconds({
+						duration: videoInfo.duration,
+						streamDuration: videoInfo.streamDuration,
+					}) * 1000,
+				),
 			);
 			const trimRegions = this.config.trimRegions ?? [];
 			const strategy =
@@ -883,7 +889,12 @@ export class ModernVideoExporter {
 		if ((this.config.trimRegions ?? []).length > 0) {
 			const sourceDurationMs = Math.max(
 				0,
-				Math.round((videoInfo.streamDuration ?? videoInfo.duration) * 1000),
+				Math.round(
+					getEffectiveVideoStreamDurationSeconds({
+						duration: videoInfo.duration,
+						streamDuration: videoInfo.streamDuration,
+					}) * 1000,
+				),
 			);
 			const trimSegments = this.buildNativeTrimSegments(sourceDurationMs);
 			if (trimSegments.length === 0) {

src/lib/exporter/videoExporter.ts

@@ -14,6 +14,7 @@ import type {
 	ZoomRegion,
 	ZoomTransitionEasing,
 } from "@/components/video-editor/types";
+import { getEffectiveVideoStreamDurationSeconds } from "@/lib/mediaTiming";
 import { AudioProcessor, isAacAudioEncodingSupported } from "./audioEncoder";
 import { buildEditedTrackSourceSegments, classifyEditedTrackStrategy } from "./editedTrackStrategy";
 import {
@@ -551,7 +552,12 @@ export class VideoExporter {
 		) {
 			const sourceDurationMs = Math.max(
 				0,
-				Math.round((videoInfo.streamDuration ?? videoInfo.duration) * 1000),
+				Math.round(
+					getEffectiveVideoStreamDurationSeconds({
+						duration: videoInfo.duration,
+						streamDuration: videoInfo.streamDuration,
+					}) * 1000,
+				),
 			);
 			const trimRegions = this.config.trimRegions ?? [];
 			const strategy =
@@ -610,7 +616,12 @@ export class VideoExporter {
 		if ((this.config.trimRegions ?? []).length > 0) {
 			const sourceDurationMs = Math.max(
 				0,
-				Math.round((videoInfo.streamDuration ?? videoInfo.duration) * 1000),
+				Math.round(
+					getEffectiveVideoStreamDurationSeconds({
+						duration: videoInfo.duration,
+						streamDuration: videoInfo.streamDuration,
+					}) * 1000,
+				),
 			);
 			const trimSegments = this.buildNativeTrimSegments(sourceDurationMs);
 			if (trimSegments.length === 0) {

src/lib/mediaTiming.test.ts

@@ -111,6 +111,15 @@ describe("getEffectiveVideoStreamDurationSeconds", () => {
 		).toBe(11.2);
 	});
 
+	it("uses the container duration when the video stream is much shorter", () => {
+		expect(
+			getEffectiveVideoStreamDurationSeconds({
+				duration: 60,
+				streamDuration: 40,
+			}),
+		).toBe(60);
+	});
+
 	it("falls back to the container duration when stream duration is missing", () => {
 		expect(
 			getEffectiveVideoStreamDurationSeconds({

src/lib/mediaTiming.ts

@@ -81,12 +81,29 @@ export function getEffectiveVideoStreamDurationSeconds({
 	duration?: number | null;
 	streamDuration?: number | null;
 }): number {
-	if (Number.isFinite(streamDuration) && (streamDuration ?? 0) > 0) {
-		return Math.max(0, streamDuration ?? 0);
+	const safeDuration =
+		Number.isFinite(duration) && (duration ?? 0) > 0 ? Math.max(0, duration ?? 0) : 0;
+	const safeStreamDuration =
+		Number.isFinite(streamDuration) && (streamDuration ?? 0) > 0
+			? Math.max(0, streamDuration ?? 0)
+			: 0;
+
+	if (safeDuration > 0 && safeStreamDuration > 0) {
+		const gapSeconds = safeDuration - safeStreamDuration;
+		const largeMismatchThresholdSeconds = Math.max(2, safeDuration * 0.1);
+		if (gapSeconds > largeMismatchThresholdSeconds) {
+			return safeDuration;
+		}
+
+		return safeStreamDuration;
 	}
 
-	if (Number.isFinite(duration) && (duration ?? 0) > 0) {
-		return Math.max(0, duration ?? 0);
+	if (safeStreamDuration > 0) {
+		return safeStreamDuration;
+	}
+
+	if (safeDuration > 0) {
+		return safeDuration;
 	}
 
 	return 0;