Fix NS_E_VBRMODE_MISMATCH (0XC00D1B9D) in Windows Media

Getting that 0XC00D1B9D error when you're trying to encode a Windows Media file is a pain, especially if you've been at it for hours. Let me walk you through the fix—it's simpler than it looks.

The Fast Fix

This error means your Windows Media Encoder (WME) project has multiple audiences (like different bitrate targets), but for the same source video or audio, those audiences are using different VBR (Variable Bit Rate) encoding modes. One audience might be set to quality-based VBR while another uses constrained VBR. WME won't let that slide.

Here's exactly what to do, step-by-step:

1. Open your Windows Media Encoder project file (.wme) or start a new one. If you're mid-session, close and reopen the encoder to start fresh.
2. Go to the Session menu and pick Properties. You'll see the Properties dialog open.
3. On the left, click Compression. That's where the audience settings live.
4. In the Target audience(s) list, you'll see one or more entries. Each one is a separate audience. If you only have one audience, the error wouldn't usually appear—so you likely have two or more.
5. Select the first audience and click Edit. This opens the Windows Media Profile Editor.
6. Inside the editor, look for the Video or Audio tab (depending on what you're encoding). Under Encoding mode, you'll see options: Constant bit rate (CBR), Variable bit rate (VBR) – quality, VBR – constrained, VBR – unconstrained. Take note of which is selected.
7. Without closing, go back to the Properties dialog and repeat step 5 for each audience in the list. Compare them. The rule is: all audiences that reference the same source index must use the exact same VBR mode. That means if one is on "VBR – quality", they all need "VBR – quality". Same bitrate settings too.
8. If any audience differs, click on that audience, click Edit, and change its encoding mode to match the others. Apply the change.
9. After you fix all audiences to match, click OK to close the Properties dialog.
10. Try encoding again. The error should be gone.

After you apply the matching mode, the encoder should start processing without complaint. If you still see the error, double-check you didn't miss an audience—sometimes WME creates hidden duplicate audiences.

Why This Works

WME's architecture expects the same source (like a video file) to be encoded in a consistent way across all target audiences. The idea is that each audience is just a different bitrate version of the same source. If you mix VBR with CBR, or different VBR sub-types (quality vs constrained), the encoder can't produce a clean unified output. The error code 0XC00D1B9D is literally the encoder saying, "I can't make one file from mismatched recipes." By forcing all audiences to the same VBR mode, you remove that conflict.

In my experience, the most common slip-up is using "VBR – quality" for one audience (because you want best quality) and "VBR – constrained" for another (because you need a max bitrate). Don't do that. Pick one mode and stick with it across all audiences.

Less Common Variations

Sometimes the issue isn't obvious in the audience list. Here are other places it hides:

• Multiple source indexes. If your project has more than one source (like two video files or a video plus an audio-only stream), each source has its own index. The error might only show for a specific index. Check the Sources tab in Properties—ensure each source's encoding settings are consistent across all audiences that use that source. You might need to re-add the source with matching settings.
• Imported profiles. If you imported a custom profile (.prx or .wmp) for one audience but used the default for another, the modes could differ. Open each profile in the Profile Editor and compare the encoding mode manually.
• Hidden default audiences. Windows Media Encoder sometimes includes default audiences (like "PDA" or "High speed") that you didn't add. Go to Compression > Target audience(s) list and remove any you don't need. Then for the ones you keep, verify they all match.
• Audio-only projects. The same rule applies to audio sources. If you're encoding a podcast or music, check the audio encoding mode under the Audio tab in the Profile Editor. Mixing CBR and VBR on audio triggers the same error.

If none of that helps, try starting over: create a new project, add your source, and manually set all audiences to the same VBR mode before adding any other settings. That forces consistency from the start.

How to Prevent This Going Forward

Once you fix it, you don't want to see it again. Here's what I tell my techs:

• Before you add a second audience, set the encoding mode for the first one exactly how you want it. Then when you add more audiences, use the Copy from existing option instead of creating from scratch. That copies the settings, including the VBR mode.
• If you must create audiences separately, double-check the encoding mode tab in the Profile Editor for each one before you start encoding. It takes 30 seconds and saves you the headache.
• Use constrained VBR if you're not sure what to pick. It's the most flexible—gives you good quality without blowing up file size unpredictably. Then all audiences inherit that mode.
• Keep a consistent naming convention for your profiles. If you name them "High quality VBR" and "Low quality VBR", you'll remember they both use VBR.

That's it. The error is stubborn, but the fix is dead simple once you know where to look. Now go encode.