動画クロップツール
ブラウザで動画を正確な寸法にクロップ。
Drop your Video file here
or click to browse · max 500 MB
Settings
Crop to 1280x720 starting at (0, 0). Width and height must be even numbers.
128k for speech · 192k for general use · 320k for music
FFmpeg WASM (~25MB) will be downloaded on first use and cached by your browser.
Video Crop
Crops video to a specific rectangular region, removing unwanted edges or areas. Set exact pixel coordinates for the crop area including width, height, and position offset. Useful for removing black bars, focusing on a subject, or creating square videos for social media.
用途
- Removing black bars from videos (letterbox/pillarbox)
- Creating square or portrait crops for Instagram and TikTok
- Focusing on a specific area or subject in the frame
- Removing watermarks or UI elements from screen recordings
- Reformatting landscape video for vertical social media
使い方ガイド
- Click the upload area or drag and drop your video file
- Set the desired crop Width and Height in pixels
- Set X and Y offset (top-left corner of crop area)
- Click 'Convert to .MP4' to crop the video
- Preview and download the cropped result
仕組み
Upload a video file, set the crop dimensions (width, height) and offset position (X, Y), then click Convert. FFmpeg WASM applies the crop filter and re-encodes with H.264.
ヒントとベストプラクティス
- Width and height must be even numbers for H.264 encoding
- For center crop: X = (original_width - crop_width) / 2
- Social media sizes: 1080x1080 (square), 1080x1920 (portrait), 1920x1080 (landscape)
- Use Video Resize after cropping to scale to a specific resolution
よくある質問
How do I know what dimensions to use?
For 16:9 to square, crop to equal width and height. For 16:9 to 9:16 (portrait), swap the dimensions. Common social media sizes: Instagram (1080x1080), TikTok (1080x1920), YouTube (1920x1080).
What do X and Y offset mean?
X is the horizontal offset from the left edge, Y is the vertical offset from the top edge. Both default to 0 (top-left corner). Center crop: set X=(original_width-crop_width)/2 and Y=(original_height-crop_height)/2.
Will cropping reduce file size?
Yes, since you're reducing the number of pixels per frame, the resulting video will be smaller. The exact reduction depends on how much you crop.
プライバシーとセキュリティ
このツールはWebAssembly（WASM）にコンパイルされたFFmpegを使用しています。WASMバイナリ（約25MB）は初回使用時にCDNからダウンロードされ、ブラウザにキャッシュされます。すべてのファイル処理はお使いのデバイス上でローカルに行われ、ファイルがサーバーにアップロードされることは一切ありません。そのため、機密性の高いメディアファイルも安全に処理できます。大きなファイルの場合、デバイスのCPUや利用可能なメモリによって処理に時間がかかることがあります。