diff --git a/js/nostr/nip71.js b/js/nostr/nip71.js
index 928010ae..4510f77d 100644
--- a/js/nostr/nip71.js
+++ b/js/nostr/nip71.js
@@ -1492,10 +1492,13 @@ function detectImetaMediaKinds(tags = []) {
   return { hasVideo, hasAudio };
 }
 
-// Unambiguous audio-only file extensions. `.ogg` is deliberately excluded — it
-// can be video (Theora) and bitvid maps it to video/ogg — so `.ogg` is only
-// treated as audio when an `imeta m audio/*` tag says so.
-const AUDIO_ONLY_URL_PATTERN = /\.(mp3|m4a|aac|wav|flac|opus|oga|weba)(?:[?#]|$)/i;
+// Unambiguous audio-only file extensions (the fallback when an event carries no
+// `imeta m audio/*` hint). `.ogg` is deliberately excluded — it can be video
+// (Theora) and bitvid maps it to video/ogg — so `.ogg` is only treated as audio
+// when an `imeta m audio/*` tag says so. `.f4a`/`.m4b` are AAC-in-MP4 audio
+// (podcasts/audiobooks) — NOT `.mp4`/`.m4v`, which are video.
+const AUDIO_ONLY_URL_PATTERN =
+  /\.(mp3|m4a|m4b|f4a|aac|wav|flac|opus|oga|weba|mka)(?:[?#]|$)/i;
 
 // Whether a (converted) video object is an audio-only note — a podcast/music
 // note published as a native kind-30078. bitvid has no <audio> player, so these
diff --git a/tests/video-schema-and-conversion.test.mjs b/tests/video-schema-and-conversion.test.mjs
index 461491cc..56de0dfb 100644
--- a/tests/video-schema-and-conversion.test.mjs
+++ b/tests/video-schema-and-conversion.test.mjs
@@ -226,6 +226,40 @@ test("isAudioOnlyVideoObject flags a cached .ogg only when imeta says audio", ()
   );
 });
 
+test("audio/mp4 podcast (imeta) is filtered even though it would play", () => {
+  // Real case: Nodesignal-Talk E19 — m audio/mp4 + .f4a URL. AAC-in-MP4 plays in
+  // a <video> (audio + poster), but it's still a podcast → out of the video grid.
+  const podcast = {
+    id: "66c13a72",
+    content: JSON.stringify({
+      version: 3,
+      title: "Nodesignal-Talk E19",
+      url: "https://relay.example/talk.f4a",
+      videoRootId: "root-nodesignal",
+    }),
+    tags: [
+      ["imeta", "url https://relay.example/talk.f4a", "m audio/mp4", "duration 3309"],
+    ],
+  };
+  assert.equal(convertEventToVideo(podcast).invalid, true);
+});
+
+test("audio-only .f4a/.m4b URL with no imeta is filtered (fallback)", () => {
+  assert.equal(
+    isAudioOnlyVideoObject({ url: "https://x/a.f4a", magnet: "", tags: [] }),
+    true
+  );
+  assert.equal(
+    isAudioOnlyVideoObject({ url: "https://x/book.m4b", magnet: "", tags: [] }),
+    true
+  );
+  // .mp4/.m4v remain video and must NOT be filtered by the extension fallback.
+  assert.equal(
+    isAudioOnlyVideoObject({ url: "https://x/clip.mp4", magnet: "", tags: [] }),
+    false
+  );
+});
+
 test("isAudioOnlyVideoObject keeps a normal cached video object", () => {
   assert.equal(
     isAudioOnlyVideoObject({