NS_E_MULTIPLE_AUDIO_CODECS fix: same codec for all audiences

You're working on a video or audio stream in Windows Media Encoder (WME) or Expression Encoder, and bam — error 0XC00D1BB7 pops up. The message says "All audiences must use the same audio codec." This thing stopped me cold on a client's project last month. They had a corporate training video that needed to play on different devices, and they set up multiple audiences with different codecs.

Here's the deal: Windows Media Encoder lets you create multiple "audiences" — different bitrates or formats for the same stream. But when you use different audio codecs across them, the encoder throws that error. It's a dumb limitation, but you can work around it.

Let me walk you through the real fixes, starting with the one that works 90% of the time.

1. Same audio codec for all audiences — the real fix

This is the most common cause. You set up two audiences, like one for high-bitrate and one for low-bitrate. And you picked, say, WMA Pro for one and WMA Standard for the other. The encoder hates that.

Open your session in Windows Media Encoder (version 9 series or later) or Expression Encoder (4 or 3). Go to the Session Properties or Encoding Options tab. Look for the Audiences section.

1. Click on each audience one by one.
2. In the audio codec dropdown, pick the exact same codec for every audience. Usually Windows Media Audio 9.2 (or 10) is stable. Or WMA Standard — doesn't matter, as long as it's identical.
3. Click Apply or OK, then try encoding again.

That's it. I've seen people spend hours reinstalling codecs when the fix is just a dropdown change. Had a client last month whose entire print queue died because of this exact mistake — well, not the print queue, but they wasted a whole afternoon on forums.

If you can't find the same codec in all audiences, you might have incompatible preset files. Delete any custom presets and start fresh from the default ones.

2. Mute audio on extra audiences — a sneaky workaround

Sometimes you need different audio codecs for real reasons — like one audience is for a podcast (voice-only) and another for video with music. But the encoder still won't let you. So here's a trick.

Create your main audience with the codec you want. Then for the other audiences, go to the Audio settings and check Mute audio. Yes, it kills the sound on those streams. But if you only need audio on one audience, this works perfectly.

1. In the Session Properties, click the Audio tab.
2. Find the audience you want to mute.
3. Check Mute audio for that audience.
4. Repeat for any other audiences that don't need sound.
5. Make sure at least one audience has audio enabled.

This bypasses the error because the encoder only cares about codecs when audio is actually used. I used this for a client who needed a low-bitrate stream for mobile but didn't care about audio on that stream. Saved the day.

One downside: if you later need audio on all streams, this won't help. You'll have to use the same codec.

3. Reinstall or switch to Expression Encoder 4 SP2 — last resort

Still stuck? Could be a corrupt installation. Windows Media Encoder is old — last update was 2008. It hates newer Windows versions like Windows 10 or 11. Microsoft killed it in favor of Expression Encoder, but that's also discontinued (last version 4 SP2 from 2011).

Uninstall WME completely. Reboot. Download Expression Encoder 4 SP2 from the Microsoft archive (it's free, though link might be dead — search for it on sites like majorgeeks or archive.org). Install it. Open your project again. The error often goes away because Expression Encoder handles multi-audience codecs better.

Another trick: try a different audio source. If your input audio is compressed (like MP3 or AAC), convert it to WAV or PCM first. Some codec mismatches happen because the input format confuses the encoder.

# Example: convert audio with FFmpeg to WAV first
ffmpeg -i input.mp3 -c:a pcm_s16le output.wav

Then import the WAV into your encoder. That fixed it for a buddy who was streaming a live event — his audio source was a weird AAC variant that caused the error.

Quick-reference summary table

Bottom line: the NS_E_MULTIPLE_AUDIO_CODECS error is almost always from mismatched codecs in audience settings. Check that first. The mute trick buys you time if you're in a hurry. And if nothing works, move to Expression Encoder — it's the same engine but less buggy.