I've had the same problem for months. Even when it's set to a hundred. It's driving me crazy.

Hi,

When an effect looks perfect in the preview but changes drastically upon export, it usually points to differences in rendering between the preview and the final export process, especially at higher resolutions like 4K.

Here's a breakdown of potential causes and solutions you can try:

1. Rendering Discrepancy (Preview vs. Export):

   • Why it happens: The editor preview often uses a lower-quality or faster rendering method to keep things smooth while you edit. The final export, especially at 4K, uses a more intensive process that can sometimes interpret effects differently or apply compression artifacts that subtly change the look.
   • Solution 1: Overcompensate the Blur: Since you know the blur weakens on export, try increasing the blur setting significantly higher in the editor than what looks "perfect" there. Maybe push it to 70, 80, or even higher. Export a short test clip to see how much compensation is needed to achieve the desired level of background obscurity in the final 4K file.
   • Solution 2: Test Lower Resolution Export: Export the exact same project at 1080p instead of 4K. Does the blur hold up better? If yes, it strongly suggests the issue is related to the high-resolution rendering process in CapCut. You might need to overcompensate more heavily for 4K.

2. Type of Blur Effect:

   • Why it happens: CapCut offers several blur effects (e.g., Basic Blur, Gaussian Blur, Halo Blur). Some might render more consistently than others across different resolutions.
   • Solution: Try using a different type of blur effect from CapCut's library and see if it exports more reliably at 4K.

3. Export Settings Combination:

   • Why it happens: While 4K, 30fps, MP4 seems standard, sometimes the specific combination, including the bitrate (which affects compression), can interact poorly with certain effects.
   • Solution 1: Adjust Bitrate: If CapCut allows manual bitrate control during export, try exporting with a higher bitrate (less compression) or select a "Higher Quality" preset if available. Conversely, sometimes a different codec setting (if available, like H.265 instead of H.264, though MP4 usually uses H.264) might behave differently.
   • In the export settings, set the bitrate between 35,000 and 45,000 kbps for 4K videos to maintain high-quality visuals.
   • Solution 2: Change Frame Rate (Temporarily): Just as a test, try exporting at 4K/60fps or 4K/24fps. Does the blur behave differently? This helps isolate if the 30fps setting is specifically interacting poorly.

4. Software Glitch / Cache Issues:

   • Why it happens: Sometimes temporary files or a minor bug can cause unexpected behavior.
   • Solution 1: Update CapCut: Ensure you are using the absolute latest version of CapCut from your app store or the official website (for desktop). Bug fixes are common.
   • Solution 2: Clear Cache: Go into CapCut's settings within the app and look for an option to clear the cache. If not available there, check your phone's app settings for CapCut and clear the cache from there.
   • Solution 3: Restart Device: A simple restart of your phone or computer can sometimes resolve temporary glitches.

5. Alternative Blurring Method:

   • Why it happens: If the standard effect is unreliable for export, recreating the effect manually might work better.
   • Solution:
     • Duplicate your main video clip. Place the duplicate on a layer below the original.
     • Apply the strong blur effect to this bottom layer clip.
     • On the top layer (the original, unblurred clip), use CapCut's "Remove Background" feature (if your subject is suitable for automatic removal) OR use masking tools (like a circular or linear mask with heavy feathering) to cut out your main subject, revealing the blurred background layer underneath. This separates the blur process from the main clip rendering, which might export more predictably.

6. Verify Project and Export Resolution:

   Ensure that both your project's resolution and the export settings are consistent. Mismatched resolutions can lead to unexpected visual effects.

   • Check Project Resolution:

     • Open your project in CapCut.

     • Tap on the "Project Settings" (gear icon).

     • Confirm that the resolution matches your intended output (e.g., 4K).

   • Set Export Resolution:

     • When exporting, select the same resolution as your project to maintain visual consistency.

7. Disable Smart HDR Feature:

   The Smart HDR feature can sometimes alter the appearance of effects:

   • Turn Off Smart HDR:

     • Before exporting, go to the export settings.

     • Toggle off the "Smart HDR" option to prevent automatic adjustments that might affect the blur effect.

8. Render Effects Before Exporting:

   Unrendered effects may not appear correctly in the final export:

   • Pre-Render Effects:

     • Tap the play icon to preview the video within the app.

     • Allow CapCut to fully process and play through the entire timeline. This ensures all effects are rendered properly before exporting.

In summary, start with these steps:

1. Increase the blur strength way beyond 50 in the editor.
2. Try exporting a short test clip. Repeat until the exported clip looks right.
3. If that fails, try a different type of blur effect.
4. Ensure CapCut is updated and clear its cache.
5. Experiment with slightly different export settings (like bitrate or a 1080p test).

Hopefully, one of these approaches, especially overcompensating the blur amount, will resolve the issue for your 4K export. By following these steps, you should be able to maintain the integrity of the blur effect in your exported video.