NS_E_MULTIPLE_AUDIO_FORMATS (0XC00D1BB8) Fix for WMP 7

Quick answer: Re-encode your source so every audience uses the same audio codec, sample rate, and channels — or force a single format in your publishing point profile.

I know this error is infuriating, especially when you're on a deadline and Windows Media Encoder just refuses to publish. NS_E_MULTIPLE_AUDIO_FORMATS (0XC00D1BB8) usually shows up the moment you hit Start Publishing on a multi-audience stream. The short version: WMP 7 can't handle profiles where audience A is WMA 9 at 44.1 kHz stereo and audience B is WMA 7 at 22 kHz mono. It needs one audio format across the board. That's it. That's the whole error.

This first bit me back in 2003 when I was setting up a 56k + broadband dual-audience stream for a local radio station. The video side was fine — different bitrates, different resolutions. But I'd lazily let the wizard pick audio per audience, and WMP 7 choked immediately on playback. The fix is less about WMP and more about your encoder profile.

What actually triggers 0XC00D1BB8

Windows Media Player 7 shipped with strict assumptions about multi-audience ASF files. Every audience in the file must share identical audio properties:

• Same audio codec (WMA 7, WMA 8, WMA 9, WMA 9.1, etc.)
• Same sample rate (22.05 kHz, 32 kHz, 44.1 kHz, 48 kHz)
• Same channel count (mono or stereo)

Bitrate can vary between audiences — that's the whole point of multi-bitrate. Sample rate, codec, and channels cannot. If you're mixing a 20 kbps mono 22 kHz audience with a 128 kbps stereo 44.1 kHz audience, you'll get 0XC00D1BB8 every single time.

Fix it in Windows Media Encoder

1. Open your session in Windows Media Encoder 9 Series (or whichever version you're running).
2. Go to Properties → Output tab and click Manage next to the profile dropdown.
3. Select your custom profile and click Edit. If you're using a stock profile like "Broadband (768 kbps)", duplicate it first — you can't edit built-ins directly.
4. Switch to the Audiences tab. You'll see each audience listed with its own bitrate and codec settings.
5. Open the first audience's audio settings. Note the codec, sample rate, and channels.
6. For every other audience, force the same codec, sample rate, and channels. Only change the bitrate.
7. Click Save, then OK, then restart the encoder session.

For most legacy WMP 7 targets I'd standardize on WMA 9 at 44.1 kHz stereo for anything above 64 kbps, and drop to 22.05 kHz stereo (not mono) for the low-bitrate audience. Mono is technically valid as long as every audience is mono, but WMP 7 handles stereo downmix more predictably.

If you're using a Windows Media Services publishing point

Same rule applies, different place. Open the publishing point properties, expand Sources, and check each stream's audio encoder settings. You can also nuke the mismatch from a command prompt if you're automating this:

cscript //nologo %SystemRoot%\System32\AdminScripts\adsutil.vbs ENUM W3SVC/1/ROOT/WMSPublishPoint

Look for the AudioCodec, AudioSampleRate, and AudioChannels values on each child node. If they differ, that's your culprit.

Alternative fixes when the profile route won't cooperate

Sometimes the encoder GUI lies to you and the profile looks fine but the error persists. Try these in order:

• Rebuild the profile from scratch. Corrupted audience blocks are real. Duplicate the stock "Broadband" profile, strip the audio on every audience, then re-add it identically.
• Swap to a single-audience profile temporarily. If publishing works with one audience, the problem is definitely a format mismatch, not your source file.
• Check the source file's audio. If your input is a 48 kHz WAV and one audience is 44.1 kHz, the encoder has to resample. Some encoder builds throw NS_E_MULTIPLE_AUDIO_FORMATS instead of resampling cleanly. Convert the source to match first with:

wmplayer /convert "C:\input.wav" /audio 44100 /channels 2

Or use ffmpeg if you've got it handy — ffmpeg -i input.wav -ar 44100 -ac 2 -c:a wmav2 output.wma is faster and doesn't fight you.

Heads up: if you're targeting anything newer than WMP 7, this restriction relaxes. WMP 9 and 10 handle mixed audio formats across audiences fine. Only force single-format audio if you genuinely need WMP 7 compatibility — which, in 2024, you probably don't unless you're maintaining legacy infrastructure.

Prevention tip

Save a known-good multi-audience template with matched audio properties and never touch the audio section again. I keep one called "LegacyMP7.prx" that I've cloned for every legacy streaming gig since 2005. Saves about 20 minutes of head-scratching every time someone digs an old encoder out of a closet. Also — document which WMP versions you're actually targeting in the project notes. Half the 0XC00D1BB8 tickets I've seen came from someone forcing WMP 7 compatibility they didn't need.