Convert video
Convert video writes MP4 (H.264), WebM (VP8), or MOV. Same-family remux uses stream copy when it can; otherwise it re-encodes. Exotic inputs may decode and still fail an encode, I'll show an error rather than a broken file.
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Video
Convert, trim, compress, GIF, extract audio, mute, resize, rotate, and merge video in the tab with FFmpeg.wasm. The clip isn't uploaded.
Runs in your browser · Nothing uploaded
- Convert videoMP4, WebM, MOV, MKV, AVI, FLV, and more — re-encoded in your browser.Runs in your browser · Nothing uploaded
- Trim videoCut a clip to a start and end time, on this device.Runs in your browser · Nothing uploaded
- Compress videoShrink a clip with CRF quality or a target size estimate.Runs in your browser · Nothing uploaded
- Video to GIFTurn a clip into a palette-optimized GIF in the browser.Runs in your browser · Nothing uploaded
- Extract audioPull the soundtrack out as MP3, WAV, or AAC.Runs in your browser · Nothing uploaded
- Mute videoStrip the audio track and keep the picture.Runs in your browser · Nothing uploaded
- Resize videoScale a clip to a width, keeping aspect or forcing a size.Runs in your browser · Nothing uploaded
- Rotate videoRotate a phone clip 90, 180, or 270 degrees.Runs in your browser · Nothing uploaded
- Merge clipsConcatenate two or more clips into one file.Runs in your browser · Nothing uploaded
- Extract framesPull stills from a clip into a zip, in the browser.Runs in your browser · Nothing uploaded
- Reverse videoPlay a clip backwards. Caps long files at 20 seconds.Runs in your browser · Nothing uploaded
- Change video speedSpeed up or slow down a clip with setpts and atempo.Runs in your browser · Nothing uploaded
- Crop videoCut a rectangle out of the frame. Numeric crop, like the image tool.Runs in your browser · Nothing uploaded
- Split videoCut a clip into N equal parts and download a zip.Runs in your browser · Nothing uploaded
- Watermark videoOverlay a logo image on a clip. Drop the clip first, then the logo.Runs in your browser · Nothing uploaded
- Replace audioSwap the soundtrack. Drop the clip first, then the new audio.Runs in your browser · Nothing uploaded
- Video contact sheetA grid of frames as one PNG.Runs in your browser · Nothing uploaded
- BoomerangForward then reverse, concatenated. Caps at 8 seconds.Runs in your browser · Nothing uploaded
About Video
Video is the category upload sites love most: a 200 MB file, a progress bar, an email with a link. These pages load a local FFmpeg build once (about 30 MB, then cached) and do the work in the tab. First visit of a video tool pays for the encoder. Your file is still not POSTed.
Outputs I actually ship are MP4, WebM, and MOV for conversion, plus GIF and extracted audio. I'm not advertising AVI, MKV, or FLV as first-class destinations. Long clips are slower here than on a rented GPU farm because they never leave the machine. That's the deal.
The encoder is GPL FFmpeg compiled to WebAssembly, single-thread, same origin. There's no COEP experiment that would break Analytics and the rest of the static site.
Tools in this category
Trim video
Trim video cuts a start and end time. Re-encode keeps the cut close to the times you typed. A 30-minute source doesn't need a 30-minute wait if you set a short window.
Compress video
Compress video uses CRF or a one-pass bitrate guessed from a target size. There's no multi-encode binary search in wasm; that would mean encoding the clip over and over in a browser tab.
Video to GIF
Video to GIF runs the two-pass palette recipe at a width and frame rate you pick. Default 320px and 10 fps is a reaction GIF, not a film print. You can limit the time range so a 30-second source doesn't become a 30-second GIF by accident.
Extract audio
Extract audio drops the picture and writes MP3, WAV, or AAC. Same job as Audio from video; two URLs because people search both phrases. No audio stream means an error, not a silent success.
Mute video
Mute video strips the soundtrack and keeps the picture, via stream copy when the container allows it. For a clip you can send without the room noise, that's enough.
Resize video
Resize video scales to a width, with aspect locked by default (even height). 4K phone clips for a slide deck are the use. Unchecking aspect will squash on purpose.
Rotate video
Rotate video is 90, 180, or 270 for the phone clip that was sideways. 90 and 270 transpose; 180 flips. Not an arbitrary-angle 3D rotate.
Merge clips
Merge clips concatenates two or more files in order. Matching formats can stream-copy; mismatches re-encode. It won't auto-letterbox mixed resolutions into a pretty sequence.
Extract frames
Extract frames writes PNGs at a frame rate you pick and zips them. High fps on a long clip will fill memory. Contact sheet is the one-image cousin.
Reverse video
Reverse video plays the clip backwards, audio included, and caps at 20 seconds so a feature film doesn't live in RAM.
Change video speed
Change video speed uses setpts and atempo. 2 is twice as fast. Pitch stays put. The whole file is re-encoded.
Crop video
Crop video is a numeric rectangle, same idea as image crop, no drag box. Even width and height.
Split video
Split video cuts N equal parts into a zip. Arbitrary cue points are trim, not this page.
Watermark video
Watermark video overlays a logo. Clip first, then the image. Alpha in the PNG is opacity.
Replace audio
Replace audio swaps the soundtrack. Clip first, then audio. The shorter stream wins.
Video contact sheet
Video contact sheet tiles frames into one PNG (3×3 at 1 fps). Short clips may not fill the grid.
Boomerang
Boomerang concatenates forward and reverse, no audio, 8 second cap. The Instagram-era loop.
Common questions
Does converting a video on these pages upload the clip?
No. After the page and the local encoder load from this origin, the bytes of your file stay in the tab. The network panel should show ffmpeg-core.wasm once, not a POST of the movie.
Why is this slower than a website that encodes “in the cloud”?
Those sites use someone else’s CPUs, which is also why they have your file. This page uses yours. A short 1080p clip is fine. A half-hour 4K dump belongs in HandBrake on the desktop.
What licence is the in-browser encoder?
FFmpeg compiled to WebAssembly, GPL. It runs in your tab; I didn't relicense it. The rest of the site is still static files. If GPL is a problem for how you use the output, that's a conversation with a lawyer, not a badge I'll fake.
Why these tools don't upload your files
There is no server to upload to. Each page is a static file, and the work happens in your browser. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network and it keeps working. The longer explanation