Does my video get uploaded anywhere?

No. The video is decoded and re-encoded entirely in your browser. It never leaves your device, and once the page has loaded it works offline.

What does each compression level do?

Smaller file targets the lowest quality and the smallest result. Balanced is the default middle ground. Higher quality keeps the most detail and produces the largest of the three. All three re-encode to H.264 video and AAC audio in an MP4.

Why did my file barely shrink, or even grow?

A video that is already small or already heavily compressed has little redundancy left to remove, so re-encoding it can match the original size or slightly exceed it. This is expected — compression works best on large, lightly compressed source files.

Will the quality drop?

Some, yes. Compression reconstructs the picture from less data, so fine detail and sharp edges soften, more so at the smaller-file setting. Pick higher quality if you want to keep the result as close to the original as possible.

Why does it fail on my browser?

Producing an MP4 needs an H.264 video encoder, which not every browser provides. If you see an error, try a recent version of Chrome or Edge, where H.264 encoding is widely available.

Video Compressor

Re-encodes the video to H.264 at a lower quality target to shrink the file. You pick how hard to compress.

What this does

This decodes your video and re-encodes the picture to H.264 at a lower quality target, with the audio re-encoded to AAC. The chosen level sets how aggressively the picture is compressed: a stronger setting throws away more detail to shrink the file, a lighter setting keeps more detail and stays closer to the original. The result is a single MP4 file.

Re-encoding always loses some detail, since the picture is reconstructed from a smaller amount of data. A file that is already small or already well-compressed may not shrink much, and can even grow slightly when re-encoded — that is normal. The output depends on what your browser can encode; some browsers cannot produce H.264 at all.

How it works

1Drop your video (MP4, MOV, WebM and more) or pick it from your device.
2Choose a compression level: smaller file, balanced, or higher quality.
3Click Compress, then download the smaller MP4.

Built with open source

Mediabunny — Converts and edits video and audio in the browser via WebCodecs. Add-on encoders cover MP3, AAC, and FLAC. · MPL-2.0

Frequently asked questions

Related tools

All Compress →

Image CompressorCompress JPG, PNG, and WebP images. Each one keeps its format. Defaults aim for the smallest file you can't tell apart from the original.PNG CompressorCompress PNG images. Color quantization cuts real size, and there's a lossless option when you need it.JPEG CompressorCompress JPG and JPEG images in bulk. A quality slider lets you trade size for sharpness.Compress MOVCompress a MOV (QuickTime) video to a smaller file in your browser. Re-encodes to H.264 at the quality level you pick.Compress MKVCompress an MKV (Matroska) video to a smaller file in your browser. Re-encodes to H.264 at the quality level you pick.