diff --git a/plugins/prebuffer-mixin/src/main.ts b/plugins/prebuffer-mixin/src/main.ts
index 97fdaeff0..ea9da6c13 100644
--- a/plugins/prebuffer-mixin/src/main.ts
+++ b/plugins/prebuffer-mixin/src/main.ts
@@ -671,6 +671,7 @@ class PrebufferSession {
 
     const { reencodeAudio } = this.getAudioConfig();
 
+    let codecCopy = false;
     if (!rtspMode || container !== 'rtsp') {
       if (this.audioDisabled) {
         mediaStreamOptions.audio = null;
@@ -683,16 +684,25 @@ class PrebufferSession {
         }
       }
       else {
-        mediaStreamOptions.audio = {
-          codec: session?.inputAudioCodec,
-        }
+        codecCopy = true;
       }
     }
     else {
       // rtsp mode never transcodes.
-      mediaStreamOptions.audio = {
-        codec: session?.inputAudioCodec,
-      }
+      codecCopy = true;
+    }
+
+    if (codecCopy) {
+        // reported codecs may be wrong/cached/etc, so before blindly copying the audio codec info,
+        // verify what was found.
+        if (session?.mediaStreamOptions?.audio?.codec === session?.inputAudioCodec) {
+          mediaStreamOptions.audio = session?.mediaStreamOptions?.audio;
+        }
+        else {
+          mediaStreamOptions.audio = {
+            codec: session?.inputAudioCodec,
+          }
+        }
     }
 
     if (mediaStreamOptions.video && session.inputVideoResolution?.[2] && session.inputVideoResolution?.[3]) {
diff --git a/plugins/prebuffer-mixin/src/rfc4571.ts b/plugins/prebuffer-mixin/src/rfc4571.ts
index 942797ff4..27b9b8d4c 100644
--- a/plugins/prebuffer-mixin/src/rfc4571.ts
+++ b/plugins/prebuffer-mixin/src/rfc4571.ts
@@ -75,8 +75,8 @@ export async function startRFC4571Parser(socket: net.Socket, sdp: string, mediaS
 
     return {
         sdp: Promise.resolve([Buffer.from(sdp)]),
-        inputAudioCodec: 'pcm',
-        inputVideoCodec: 'h264',
+        inputAudioCodec: mediaStreamOptions.audio.codec,
+        inputVideoCodec: mediaStreamOptions.video.codec,
         inputVideoResolution: undefined,
         isActive() { return isActive },
         kill,