diff --git a/src/app/(frontend)/voiceover/actions.ts b/src/app/(frontend)/voiceover/actions.ts
index 7643316..5b6da2f 100644
--- a/src/app/(frontend)/voiceover/actions.ts
+++ b/src/app/(frontend)/voiceover/actions.ts
@@ -87,7 +87,10 @@ export async function submitVoiceRecording(
     if (!(file instanceof File)) {
       return { success: false, error: "No audio file provided." };
     }
-    if (!file.type.startsWith("audio/")) {
+    // Browsers report MediaRecorder blobs as e.g. "audio/webm;codecs=opus" —
+    // strip parameters so the base type matches the collection allowlist.
+    const mimetype = file.type.split(";")[0]?.trim().toLowerCase() ?? "";
+    if (!mimetype.startsWith("audio/")) {
       return { success: false, error: "Only audio files can be submitted." };
     }
     if (file.size > MAX_AUDIO_BYTES) {
@@ -103,7 +106,7 @@ export async function submitVoiceRecording(
       },
       file: {
         data: Buffer.from(await file.arrayBuffer()),
-        mimetype: file.type,
+        mimetype,
         name: file.name,
         size: file.size,
       },