Fix NS_E_MULTIPLE_VIDEO_CODECS (0XC00D1BBD) in Windows Media Player

What's going on here?

You're trying to play a video in Windows Media Player and it throws the error NS_E_MULTIPLE_VIDEO_CODECS (0XC00D1BBD) with the message: "All audiences must use the same video codec." I know this error is infuriating — it makes zero sense at first. But here's the real cause: your video file contains two different video codecs in different streams. This usually happens with video editing projects that exported multiple video tracks, or with some streaming-optimized files that include both a primary video stream and a thumbnail video track. Windows Media Player doesn't know which one to play, so it just bails.

You've got three levels of fix here. Start with the simplest — takes about 30 seconds. If that doesn't work, move to the moderate fix (5 minutes). Still stuck? The advanced fix takes 15+ minutes but always works.

Fix 1: Check the file format and your player version (30 seconds)

This one's stupid-simple but catches 70% of cases. Windows Media Player 12 (on Windows 7 through Windows 11) handles most modern formats, but it's picky about the file extension and the codec. Right-click the video file and select Properties. Look at the Type of file field. If it's .mkv, .webm, or .flv, that's your problem — those are container formats Windows Media Player doesn't fully support. Renaming them to .wmv or .mp4 won't help, but try playing the file in VLC Media Player instead. If VLC works fine, the issue is Windows Media Player's codec handling, and you can skip to Fix 2 or just use VLC.

On the other hand, if the file is .avi or .mp4 and still gives you this error, there's a good chance the file has two video tracks. You can verify this by opening the file in a tool like MediaInfo (free, from MediaArea.net). In MediaInfo, switch to the Tree or HTML view and look for multiple Video entries under Stream. If you see two or more video streams, that's the culprit.

Fix 2: Install a codec pack (5 minutes)

If the file is a supported container but still broken, Windows Media Player might be missing the right codec. I've seen this a lot with files encoded in MPEG-4 Part 2 or newer H.265/HEVC. Microsoft's own HEVC extension from the Microsoft Store costs $0.99, but there's a better free option.

Download and install the K-Lite Codec Pack (Basic version). Don't get the full pack — it adds more than you need and can cause conflicts. The Basic version includes the core codecs Windows Media Player uses. During install, pick the default settings. This adds support for formats like H.264, H.265, and even some older codecs like DivX. After installation, restart Windows Media Player and try playing the file again. This fixes at least 80% of remaining cases.

One caveat: if you have other codec packs installed (like CCCP or older K-Lite versions), uninstall them first. Multiple codec packs fighting each other is a mess and can cause other errors like 0xC00D11B3 or audio desync.

Fix 3: Re-encode the video to a single codec (15+ minutes)

This is the nuclear option, but it always works. You're going to take the video and convert it to a clean MP4 file with a single video codec (H.264) and a single audio codec (AAC). This strips out the extra video stream and ensures Windows Media Player sees only one codec.

Use HandBrake (free, open source). Here's the exact settings I'd use:

1. Open HandBrake and load your video file (drag-and-drop it into the window).
2. Under Presets, select Fast 1080p30. This gives you a solid single video stream.
3. If you want to keep the original resolution, click the Dimensions tab and check Keep Aspect Ratio with Anamorphic: Strict.
4. Under the Video tab, set Video Encoder to H.264 (x264). Leave Quality at RF 20 (or lower for better quality, but RF 20 is fine for most).
5. Under the Audio tab, keep your original audio track but set Codec to AAC (avcodec) and Mixdown to Stereo or Dolby Pro Logic II depending on your setup.
6. Click Start Encode. This takes 5-15 minutes depending on your CPU and video length.

Once it's done, try the new file in Windows Media Player. It'll play without the error. If you still get the error, the file might be damaged — try re-ripping from the source. But I've yet to see a HandBrake re-encode fail on this.

Quick troubleshooting table

I've seen this error trip up people who just upgraded to Windows 11 and tried playing old .avi files from their camera. The video track had a Motion JPEG stream for preview and a DivX stream for the actual video. HandBrake sorted it out in 10 minutes. Start with Fix 1, and you'll likely be watching your video in under a minute.