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Media & VideoNon-AI · Runs in your browser

Video Crop & Stitch

Crop a region and time range out of a video for AI editing, then stitch the edited region back into the original — pixel-perfect, with no offset seam. Runs 100% in your browser; nothing is uploaded.

VideoCreativeAIAutomation
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Demo preview — limited to 3 uses per day. Sign up free for 1 use per tool per day + 15 bonus tokens, or try the full tool.

Like this demo? Get the full tool.

1 free use per day. No credit card required.

Use the Tool→

Overview

When you generate or edit video with AI — establishing a character on screen, upscaling a face, adjusting one part of a scene — you usually need to work on just a region of the frame, not the whole thing. The problem: once you crop that region out and run it through an AI tool, it often comes back at a different resolution. Drop it back in and it looks offset — misaligned, with a visible seam against the rest of the video.

Video Crop & Stitch fixes that. Draw a box, pick a time range, and export the region (plus a small metadata file that records exactly where it came from). After you run your AI tool on it, bring it back and the tool rescales and overlays it into the original at the exact pixel position and time — so it lands perfectly, every time.

It runs entirely in your browser. Your video is never uploaded, and nothing is stored.

How It Works

  1. Drop in your video — MP4, MOV, WebM, or AVI. It stays on your device.
  2. Draw the crop — drag the box to position it, drag the corner to resize, or snap to a preset that matches your AI tool's input size (SCAIL-2 0.5MP, common gen-video dimensions, and more).
  3. Set the time range — process the whole clip or just a segment.
  4. Export — choose Extract (just the region) or Masked (full frame, everything else filled black / green / transparent). You get the video plus a .json sidecar.
  5. Stitch back — after your AI edit, drop the original and the edited region in, load the sidecar, and get a final composited video with no offset.

Use Cases

  • AI character consistency — extract a face or subject, refine it in an upscaler or gen-video model, and merge it back seamlessly.
  • Region upscaling — send just the important part of a frame through a heavy upscaler, then restitch at full quality.
  • Scene adjustment — mask out everything except one area so an AI edits only that region, keeping the rest untouched.
  • Green-screen prep — output a masked-green version so downstream tools can key the region cleanly.

Demo vs. Full Tool

This page runs the full free tier, right in your browser: the complete crop → extract/mask → stitch-back round-trip, capped to 720p source, 15 seconds per export, and black/green masks.

Sign in and upgrade to unlock:

  • HD / 4K source video and long clips beyond 15 seconds
  • Multiple crop regions and multiple time segments in a single pass
  • Batch processing — apply the same crop and range across many files at once
  • Transparent (WebM) masks with a real alpha channel
  • Saved crop presets for the sizes you use most

Because everything is processed locally, there's no per-use cost and nothing ever leaves your device.

Technology

  • Engine: FFmpeg (WebAssembly) running client-side — crop, mask/pad, trim, and overlay compositing
  • Alignment: exact pixel-coordinate crop + a metadata sidecar, so the AI's output rescales back 1:1
  • Privacy: no uploads, no storage — the file is used only during processing

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