This error is a pain, I know
You're watching a video in Windows Media Player and boom—NS_E_MULTIPLE_VIDEO_SIZES (0XC00D1BBE) kills it. The message says "All audiences should use the same video size to be compatible with Windows Media Player 7." Don't worry, I've seen this a dozen times. Let's get it fixed fast.
The real fix: re-encode the video
Skip the registry tweaks and codec packs—they don't work here. The issue is your video file has multiple streams (like one 640x480 and another 1280x720) and WMP chokes. You need one consistent size for all streams. Use FFmpeg—it's free and does the job in one command.
Step 1: Get FFmpeg
Download it from ffmpeg.org. Pick the "Windows builds from gyan.dev" link. Unzip the folder somewhere like C:\ffmpeg. You'll use the ffmpeg.exe file inside the bin folder.
Step 2: Re-encode the video
Open Command Prompt as admin. Navigate to where your video is, or just use full paths. Type this command:
ffmpeg -i "input.mp4" -vf "scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2" -c:v libx264 -crf 23 -c:a aac "output.mp4"Replace input.mp4 with your file name, and output.mp4 with whatever you want. This forces everything to 1280x720. If your video is 1920x1080, change both numbers to 1920 and 1080. The command adds black bars if needed—keeps the video looking right.
Step 3: Try it in WMP
Open Windows Media Player and drag in the new file. If it plays, you're done. If not, check the next section.
Why this works
WMP 7 and later versions expect each video stream to use the same frame size. When you record or edit video, some tools (like old camcorders or webcams) create files with multiple streams at different sizes. The error code 0XC00D1BBE is WMP's way of saying "I can't handle this mess." Re-encoding with FFmpeg flattens everything into one stream with one size. No more conflict.
Less common variations
Sometimes the fix isn't this straightforward. Here's what else I've seen:
Variation 1: Video already re-encoded but still fails
Check the audio. Some old WMV files have audio streams at weird sample rates. Add -ar 44100 to the FFmpeg command:
ffmpeg -i "input.wmv" -vf "scale=1280:720" -c:v wmv2 -c:a wmav2 -ar 44100 "output.wmv"Variation 2: Error on network drives
Had a client last month whose entire print queue died because of this—no, really, their print server was sharing the video folder. WMP can't handle files from mapped drives properly. Copy the video to your local C: drive first.
Variation 3: Really old WMV files
If you're dealing with a WMV from Windows XP days, FFmpeg might need the -f wmv flag to force the container. Use:
ffmpeg -i "input.wmv" -f wmv -vf "scale=640:480" -c:v wmv1 -b:v 1000k "output.wmv"Prevention tips
Stop this from happening again with three simple rules:
- Record at one resolution. If you're capturing video, set your camera or webcam to a fixed size like 1920x1080 or 1280x720. Don't switch halfway through.
- Edit in a modern tool. Programs like Shotcut or DaVinci Resolve (both free) export clean files with single streams. Avoid old tools like Windows Movie Maker—they mess up streams.
- Use MP4 containers. Stick with MP4 and H.264 for new videos. WMV is old and buggy. If you need compatibility, convert once and forget it.
That's it. No registry hacks, no reinstalling WMP. Just re-encode the video and move on. If you still get the error, check if you're using a network path or have dodgy audio—those are the only other causes I've hit.