0XC00D1BAC NS_E_NONSQUAREPIXELMODE_MISMATCH Fix

Quick answer: Re-encode your source video to square pixels (1:1 pixel aspect ratio, or PAR) before adding it to your Windows Media playlist. This error means your video has mixed pixel aspect ratios across different audience indexes in your encoding profile.

I know this error is infuriating. It popped up on my screen back when I was running a help desk blog, and it tripped me up the first time too. You're encoding a video for Windows Media Services or Windows Media Encoder, and bam — NS_E_NONSQUAREPIXELMODE_MISMATCH (0XC00D1BAC). The system is telling you that the same source index in different audiences must have the same nonsquare pixel mode. In plain English: your video's pixel aspect ratio (PAR) isn't consistent across the different bitrate/quality versions you're trying to generate.

This usually happens when you have a source video that uses nonsquare pixels (like DV footage, 720×480 with a 16:9 active area, or anamorphic widescreen) and you're building a Windows Media encoding profile with multiple audiences. Each audience expects the source to come in with the same PAR, but something got crossed. Maybe your source file has a header that says "use 4:3 PAR" while the actual pixel dimensions suggest 16:9, or you imported a clip that already had different PAR metadata.

Step-by-Step Fix

1. Identify the source file. Locate the exact video file that triggers the error. Right-click it in Windows File Explorer, go to Properties > Details, and look at the Frame width, Frame height, and Aspect ratio fields. If you see values like 720×480 with "NTSC" or "DV" in the format, that's your culprit — it's using nonsquare pixels.
2. Re-encode the source to square pixels. Use a tool like FFmpeg (free, command-line) or HandBrake (GUI). I prefer FFmpeg for precision. Run this command:
   

   ffmpeg -i input_video.avi -vf "scale=720:540,setsar=1:1" -c:v libx264 -crf 18 -c:a aac -b:a 192k output_square.mp4

   Adjust the scale dimensions to match your target width. The trick is setsar=1:1 — that forces square pixels.
3. Check your encoding profile. Open Windows Media Encoder (or your custom profile in WMSDK). Go to the Session Properties > Compression tab. Under Audience, ensure every audience uses the same "Input format" — specifically the pixel aspect ratio. If one audience says "square" and another says "nonsquare (4:3)", change them all to square. You can't mix.
4. Rebuild the profile. Delete the old profile and create a new one using your square-pixel source. When you add the source video, Windows Media Encoder should now see consistent PAR metadata across all audiences.
5. Test with a single audience first. Create a profile with just one audience (say, 2 Mbps CBR) and encode a short clip. If it works, add more audiences. This isolates whether the issue is the source or the profile structure.

Alternative Fixes

If the main fix doesn't work or you're in a hurry, try these:

• Strip metadata manually. Use FFmpeg to remove all non-essential headers from the source video before re-encoding:
  

  ffmpeg -i input_video.avi -map_metadata -1 -c copy output_clean.avi

  This kills any conflicting PAR flags. Then re-encode to square pixels using the earlier command.
• Use Windows Media Encoder's "same as input" option. In the Session Properties, under Video Size, select "Same as video input" and then manually set the pixel aspect ratio to "Square (1:1)" in the advanced settings. This forces the encoder to ignore source PAR and use square pixels.
• Switch to a different encoder. If you're stuck with an old WMV workflow, try Expression Encoder (end-of-life but still runs on Windows 10/11) or use FFmpeg to encode directly to WMV with consistent settings:
  

  ffmpeg -i input_square.mp4 -c:v wmv2 -b:v 2000k -c:a wmav2 -b:a 192k output.wmv

• Check for corrupted index. If the file was partially encoded before the crash, the index might be corrupt. Use Windows Media Format SDK's WMCreateEditor or FFmpeg with -fflags +genpts to regenerate timestamps.

Prevention Tip

Always encode your source files to square pixels before you build a multi-audience Windows Media profile. It's a rule I learned the hard way: if your source is 720×480 with nonsquare pixels, scale it to 640×480 or 720×540 with 1:1 PAR. I keep a batch script handy that runs FFmpeg on any new source file I'm about to use. Trust me, it saves hours of debugging later. Also, avoid mixing different aspect ratios in the same project — if you need 4:3 and 16:9 versions, create separate profiles for each.