视频裁剪器 9:16
Convert horizontal video to vertical 9:16, square 1:1 or portrait 4:5 for TikTok, Reels and Shorts. Trim, crop and export — all in your browser. No upload, no signup, no watermark.
将视频拖到此处或点击选择
MP4、MOV、WebM — 浏览器可解码的任何格式
为获得最佳性能，请保持片段在2分钟以内
拖动控制点进行裁剪。在预览区域内拖动以重新定位裁剪矩形。
Convert horizontal video to vertical — for free, in your browser
Tools like OpusClip and Munch charge $20-50 / month to take a horizontal video and reframe it to 9:16 for TikTok, Reels and YouTube Shorts. They process on their servers and limit the number of clips you can make per month. This page does the same job 100% in your browser, with no subscription, no upload, no watermark and no monthly cap.
工作原理
We use WebCodecs, the modern browser API that exposes hardware-accelerated video encoding directly to JavaScript. When you click Export:
- The original video is decoded by your browser (whatever codec it supports).
- Each frame is drawn to an offscreen canvas at the target aspect ratio, with the chosen crop region.
- The frames are re-encoded with VideoEncoder — to H.264 for MP4 output or VP9 for WebM.
- Audio is decoded with Web Audio API and re-encoded with AudioEncoder (AAC for MP4, Opus for WebM).
- Everything is packaged into a downloadable file using a small WASM-free muxer library.
各平台宽高比
- 9:16 — TikTok, Instagram Reels, YouTube Shorts, Facebook Stories, Snapchat.
- 1:1 — Instagram feed (square posts), Twitter/X.
- 4:5 — Instagram feed (portrait posts) — takes more vertical screen space than 1:1.
- 16:9 — YouTube long-form, X video posts. Useful for re-formatting a vertical clip back to horizontal.
裁剪和重新定位
After loading a video, drag the two indigo handles on the timeline to set the start and end of your clip. Drag inside the video preview to reposition the crop rectangle — handy if the action isn't in the center of the frame. Choose "Left", "Right", "Top" or "Bottom" alignment as a starting point.
MP4 vs WebM — 如何选择？
MP4 (H.264) works literally everywhere — every social platform, every device, every editing tool. WebM (VP9) produces smaller files at the same quality but TikTok, Instagram and most editing tools will reject or transcode it. Use MP4 unless you specifically need WebM.
隐私
Your video never leaves your device. All decoding, cropping and encoding happens in your browser tab using your CPU and GPU. We don't have a server-side component for this tool. The browser tab can be closed at any time and nothing remains.
Browser support
WebCodecs is supported in Chrome 94+, Edge 94+ and Safari 16.4+. Firefox: WebCodecs support has been catching up — check version 130+. We feature-detect and show a clear notice if your browser can't handle it.
Limits
- Length: under 2 minutes works best — longer clips take time and memory.
- Resolution: anything up to 4K decodes fine; output is capped at 1080p to keep encoding fast.
- Codecs: input must be playable by your browser (MP4, MOV, WebM standard codecs all work).
Common use cases
- Repurpose a horizontal YouTube clip as a TikTok / Reel without paying OpusClip.
- Crop a podcast clip vertically for Instagram Stories.
- Trim a long screen recording down to just the interesting 30 seconds.
- Convert a square Instagram post to portrait 4:5 for better feed visibility.
- Resize a webinar recording from 16:9 to 1:1 for X (Twitter) posts.
常见问题
- 视频裁剪器会上传我的视频吗？
- 不会。视频完全在您的浏览器中使用 FFmpeg.wasm（FFmpeg 的 WebAssembly 版本）处理。您的视频永远不会离开设备——没有上传,没有服务器处理。
- 支持哪些视频格式？
- 支持 MP4、WebM、MOV、AVI 等常见视频格式。输出为 MP4（H.264）格式,兼容所有设备和平台。
- 可以进行哪些视频操作？
- 支持裁剪画面区域、修剪时长、调整分辨率和更改宽高比。您可以精确设置裁剪区域,并实时预览结果。
- 处理大视频文件需要多长时间？
- 处理时间取决于视频长度、分辨率和设备性能。由于使用 WebAssembly,速度比纯 JavaScript 快很多,但比原生应用慢。建议处理 500MB 以下的视频以获得最佳体验。
- 视频裁剪器免费吗？有使用限制吗？
- 完全免费,没有使用限制或水印。由于处理在浏览器中进行,唯一的限制是设备内存和处理能力。无需安装任何软件。