Method 1: Duplicate‑Track + Crop + Blur

Step 1: Stack Your Clips

• Place your original video on track V1.
• Copy the same clip onto track V2 above it.

Step 2: Apply Blur to V2

• Select the clip on V2.
• In the Effects panel, drag “Gaussian Blur” (or “Box Blur”) onto it.
• Adjust the blur strength until the region is fully obscured.

Step 3: Crop V2 to the Target Region

• Still on V2, add the “Crop, Scale and Rotate” effect.
• Tweak the Left/Right/Top/Bottom sliders so only your censor area remains visible.
• Everything outside that rectangle becomes transparent, revealing the sharp V1 layer underneath.

Step 4: Keyframe for Movement

• If your subject moves, click the ⚙️ icon next to each crop slider to enable keyframes.
• Scrub the timeline, adjust the crop at new positions, and Kdenlive will interpolate between frames.

Method 2: Mask + Blur

Step 1: Single‑Clip Setup

• Put your clip on V1—no duplication needed.

Step 2: Add a Simple Shape Mask

• With the clip selected, go to Effects → Mask → Simple Shape.
• Choose Rectangle (or Ellipse) and position/size it over the area to censor.
• Check “Invert mask” to apply effects inside the shape (otherwise it’s outside).

Step 3: Apply Blur Under the Mask

• Still on the same clip, add “Gaussian Blur.”
• In the Effects stack, drag Mask above Blur so only masked region is blurred.
• Increase blur strength until the area is adequately hidden.

Bonus: Solid‑Color Censor Bar

If you’d rather block out the area with a bar, use a Title Clip:

1. Add a Title → draw a filled rectangle → set its fill color to black (or any color).
2. Position it over your target region on a track above your footage.

Conclusion

Both approaches work entirely within Kdenlive. Method 1 gives you more precise cropping control, while Method 2 is quicker for static or simply moving targets. Experiment with keyframes to keep your censoring aligned, and you’ll have professional‑looking results in no time!