Video Compressor

Compress video without uploading

When your browser can handle the video, it’s compressed on your device and nothing is sent to us. The page tells you which way it will go before you start.

How compressing in your browser works

Most online compressors upload your video, compress it on their server and send it back. Here, when your browser can handle the video, the whole job happens on your own device instead: the page reads the file from your disk, decodes it, encodes a smaller MP4 and keeps it in the browser until you save it. The video never crosses the network, so there’s no upload to wait for and nothing on our side to delete.

Two pieces make that possible. WebCodecs is the set of video decoders and encoders built into modern browsers, which use your device’s graphics hardware where it has it. Mediabunny, an open-source library, reads the video’s container and writes the new MP4. The result is the same kind of file our server makes: H.264 or H.265 with AAC sound, no metadata, and, for a target size, measured and done again if it came out too big.

Before you start, the line under the options says where the video will be compressed: This device or Our server, and why. When your browser can’t handle a video, the page switches to our server and says so; nothing is uploaded until you press the button to start. When both are possible, you choose.

What compressing on your device means

  • Your device does the work

    The speed depends on your computer or phone, not on your connection. A long video on a slow upload no longer means waiting for the upload, then for the download.

  • No size or length cap

    Our server’s 1 GB, 60-minute and 5-a-day limits don’t apply. The browser only needs free storage for the result, about one and a half times the target size.

  • No metadata, here either

    Like our server, the browser writes the MP4 without metadata, so the location and the details of the phone or camera stay out of the file you send.

  • Gone when you leave

    The result sits in the browser’s private storage while you’re on the page, and is deleted when you remove it or go to another page. A file left behind by a closed tab is cleared the next time you compress, once it’s 1 day old.

How to check that nothing is uploaded

  1. 01

    Open the Network panel

    On a computer, open your browser’s developer tools (F12, or Command-Option-I on a Mac) and choose Network. Keep it open while you compress.

  2. 02

    Compress on This device

    Add a video, check that the line under the options says This device, and start compressing.

  3. 03

    Look for your video

    Sort the list by size. You’ll see the page load its own code and send a few tiny anonymous usage counts, but no request that carries your video. When a video does go to our server, the same panel shows its upload in large parts.

Questions

Can’t find your answer? Write to feedback@videocompressor.xyz.

When is my video uploaded after all?

When your browser can’t do the job: file types it can’t read (AVI, WMV and FLV, for example), video or sound it can’t decode (such as HEVC on Windows without Microsoft’s extension, ProRes, or AC-3 sound), HDR video, too little free storage in the browser, or the compatibility option for old devices. The page names the reason before you start.

Why is HDR video compressed on your server?

Turning HDR into ordinary colors takes tone mapping, which browsers can’t do yet. Without it the video would come out gray and washed out, so HDR, which most recent iPhones record, goes to our server, where the colors are converted properly.

What happens to a video that goes to your server?

It’s uploaded over an encrypted connection, compressed, and deleted with the result 2 hours after compressing; a storage rule removes anything left after 1 day as a backstop. Nobody else can see it. We keep a record of the job, such as the file name, size, settings and a keyed hash of your IP address, but never the video, for 30 days.

Does it work on my phone?

Often, but we don’t promise it. Phone browsers have less memory and some lack the encoders, and most iPhone videos are HDR, so many phone videos go to our server. The page tells you which one it will use before you start, so you can decide.

Can I still choose your server?

Yes. When both are possible, pick Our server under the options, for instance when your browser can’t make H.265 videos. If the browser runs out of memory or storage partway, the page offers our server too, and waits for you to start again.

Are Google Drive and Dropbox videos uploaded?

Not to us: your browser downloads the file from Drive or Dropbox and treats it like one from your disk. A video from a link is different: our server downloads and compresses it, because the browser can’t read files from other sites.

Is compressing in the browser slower?

It depends on your device. A recent computer is usually quick, and it skips the upload and download, often the slowest part for a big video. An older phone can take a while; keep the tab open and in front until it’s done.

Does compressing in my browser use my data?

Only to load the page and its encoders, a few megabytes at most. The video itself isn’t sent anywhere, so a big file doesn’t eat into a mobile data plan the way an upload would.

More ways to compress video

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