fix(studio): address review follow-ups

packages/core/src/lint/utils.ts

@@ -59,12 +59,18 @@ export function extractBlocks(source: string, pattern: RegExp): ExtractedBlock[]
 }
 
 export function findRootTag(source: string): OpenTag | null {
-  const bodyMatch = source.match(/<body\b[^>]*>([\s\S]*?)<\/body>/i);
-  const bodyContent = bodyMatch ? (bodyMatch[1] ?? source) : source;
+  const bodyOpenMatch = /<body\b[^>]*>/i.exec(source);
+  const bodyCloseMatch = /<\/body>/i.exec(source);
+  const bodyStart = bodyOpenMatch ? bodyOpenMatch.index + bodyOpenMatch[0].length : 0;
+  const bodyEnd =
+    bodyOpenMatch && bodyCloseMatch && bodyCloseMatch.index > bodyStart
+      ? bodyCloseMatch.index
+      : source.length;
+  const bodyContent = bodyOpenMatch ? source.slice(bodyStart, bodyEnd) : source;
   const bodyTags = extractOpenTags(bodyContent);
   for (const tag of bodyTags) {
     if (["script", "style", "meta", "link", "title"].includes(tag.name)) continue;
-    return tag;
+    return { ...tag, index: tag.index + bodyStart };
   }
   return null;
 }

packages/studio/src/player/hooks/useTimelinePlayer.test.ts

@@ -195,6 +195,35 @@ describe("anonymous timeline identity", () => {
     expect(new Set(elements.map((element) => element.key)).size).toBe(2);
     expect(elements.map((element) => element.selectorIndex)).toEqual([0, 1]);
   });
+
+  it("reads media metadata from owner-window media elements", () => {
+    const doc = createDocument(`
+      <div data-composition-id="main" data-start="0" data-duration="8">
+        <div class="clip video-card" data-start="0" data-duration="3" data-track-index="0">
+          <video src="/clip.mp4" data-source-duration="12"></video>
+        </div>
+      </div>
+    `);
+    const hostEl = doc.querySelector(".video-card");
+    const video = hostEl?.querySelector("video");
+    if (!hostEl || !video) throw new Error("missing video test fixture");
+    Object.defineProperty(video, "defaultPlaybackRate", {
+      value: 1.5,
+      configurable: true,
+    });
+
+    const element = createTimelineElementFromManifestClip({
+      clip: createClip({ kind: "video", tagName: "div" }),
+      fallbackIndex: 0,
+      doc,
+      hostEl,
+    });
+
+    expect(element.tag).toBe("video");
+    expect(element.src).toBe("/clip.mp4");
+    expect(element.sourceDuration).toBe(12);
+    expect(element.playbackRate).toBe(1.5);
+  });
 });
 
 describe("mergeTimelineElementsPreservingDowngrades", () => {

packages/studio/src/player/hooks/useTimelinePlayer.ts

@@ -95,7 +95,9 @@ function applyMediaMetadataFromElement(entry: TimelineElement, el: Element): voi
   const src = mediaEl.getAttribute("src");
   if (src) entry.src = src;
 
-  if (!(mediaEl instanceof HTMLMediaElement)) return;
+  const win = mediaEl.ownerDocument.defaultView ?? window;
+  const MediaElementCtor = win.HTMLMediaElement ?? globalThis.HTMLMediaElement;
+  if (typeof MediaElementCtor === "undefined" || !(mediaEl instanceof MediaElementCtor)) return;
 
   const sourceDurationAttr =
     el.getAttribute("data-source-duration") ?? mediaEl.getAttribute("data-source-duration");