From 207c8a4daf6480d697f203784f1fd422727569e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20=C3=81ngel?= <miguel.sierra@heygen.com>
Date: Wed, 21 Oct 2026 18:58:45 +0000
Subject: [PATCH] fix(engine): a muted video no longer plays at full volume in
 renders that skip the browser probe (#6044)

* fix(engine): a muted video no longer plays at full volume in renders that skip the browser probe

A <video data-has-audio="true" muted> with an audio stream is silent in
preview and in renders that run the browser probe, but a render that
skipped the probe mixed it at volume 1.0, ignoring data-volume. The audio
parser drops muted videos; the video parser kept hasAudio from
data-has-audio alone, so the auto-detect fallback re-added the sound.
The video parser now asks the same isAudibleVideoElement check.

* style(producer): format the muted-video parity test
---
 .../src/services/videoFrameExtractor.ts       |  2 +-
 .../render/stages/mutedParity.test.ts         | 37 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/packages/engine/src/services/videoFrameExtractor.ts b/packages/engine/src/services/videoFrameExtractor.ts
index b0015b3ae3..296e9e47b4 100644
--- a/packages/engine/src/services/videoFrameExtractor.ts
+++ b/packages/engine/src/services/videoFrameExtractor.ts
@@ -768,7 +768,7 @@ export function parseVideoElements(html: string): VideoElement[] {
       mediaStart: readMediaStart(el),
       playbackRate: readElementRateSpec(el),
       loop: el.hasAttribute("loop"),
-      hasAudio: hasAudioAttr === "true",
+      hasAudio: hasAudioAttr === "true" && isAudibleVideoElement(el),
       ...(isSelfOrAncestorHidden(el) ||
       (isAudibleVideoElement(el) && isMemberGroupHidden(groupsById, el))
         ? { hidden: true }
diff --git a/packages/producer/src/services/render/stages/mutedParity.test.ts b/packages/producer/src/services/render/stages/mutedParity.test.ts
index 6fff334819..b4f67a697f 100644
--- a/packages/producer/src/services/render/stages/mutedParity.test.ts
+++ b/packages/producer/src/services/render/stages/mutedParity.test.ts
@@ -1,5 +1,7 @@
 import { describe, expect, it } from "bun:test";
 import { pruneMutedBrowserMedia } from "./probeStage.js";
+import { appendAutoDetectedVideoAudio } from "./extractVideosStage.js";
+import { collectRenderMedia } from "../../renderMediaCollector.js";
 
 describe("pruneMutedBrowserMedia", () => {
   it("drops muted audio from the mix and clears hasAudio on muted video", () => {
@@ -36,3 +38,38 @@ describe("pruneMutedBrowserMedia", () => {
     expect(composition.videos[0]?.hasAudio).toBe(true);
   });
 });
+
+describe("a muted video's sound in the mix", () => {
+  const html = `<div data-composition-id="root" data-start="0" data-duration="4">
+    <video id="quiet" src="quiet.mp4" data-start="0" data-duration="4" data-has-audio="true" data-volume="0.72" muted></video>
+    <video id="voice" src="voice.mp4" data-start="0" data-duration="4" data-has-audio="true" data-volume="0.5"></video>
+    <audio id="music" src="music.mp3" data-start="0" data-duration="4" data-volume="0.19"></audio>
+  </div>`;
+  // Both files carry an audio stream, so the auto-detect fallback would add any video the parsers miss.
+  const extracted = ["quiet", "voice"].map((videoId) => ({
+    videoId,
+    metadata: { hasAudio: true },
+  }));
+
+  for (const probed of [false, true]) {
+    it(`stays out of the mix ${probed ? "after" : "without"} the browser probe`, () => {
+      const composition = collectRenderMedia(html);
+      if (probed) {
+        pruneMutedBrowserMedia(composition, [
+          { id: "quiet", tagName: "video", muted: true },
+          { id: "voice", tagName: "video", muted: false },
+          { id: "music", tagName: "audio", muted: false },
+        ]);
+      }
+      appendAutoDetectedVideoAudio(
+        composition,
+        extracted as unknown as Parameters<typeof appendAutoDetectedVideoAudio>[1],
+      );
+
+      expect(composition.audios.map(({ id, volume }) => [id, volume])).toEqual([
+        ["music", 0.19],
+        ["voice-audio", 0.5],
+      ]);
+    });
+  }
+});