Video Compressor | Browser Kitty

Operation demo See the basic workflow in a short video.

About this tool

Video Compressor uses ffmpeg.wasm to re-encode video files locally in the browser. You can reduce file size by changing resolution and video bitrate without uploading the source video to a server.

H.264 is the practical default, while H.265 and VP9 are also available. The tool estimates output size from duration and settings, then lets you preview, save, or share the compressed result.

Good for

Shrink phone videos before sending them by email or chat
Reduce resolution or bitrate to save storage space
Compress private videos without uploading them to an online conversion service

What it can do

Key capabilities available in this tool.

Resolution controls
Bitrate controls
Remove audio
Local browser processing

How to use

Select a video file or drag and drop it into the tool.
Review the suggested resolution and video bitrate.
Adjust codec, frame rate, audio removal, or other options when needed.
Check the estimated output size and start compression.
Preview the result, then save or share the compressed video.

Supported

Video codecs: H.264 / H.265 / VP9. H.264 is recommended when unsure.
Controls: resolution, video bitrate, frame rate, compression speed, audio bitrate, remove audio, and metadata retention.
Info: size, duration, resolution, estimated total bitrate, measured frame rate, and format.
Output: compressed preview, file download, and sharing where supported.

Limitations and notes

ffmpeg.wasm runs as CPU-based WebAssembly and does not use hardware video encoding.
Long or high-resolution videos can take significant time and may fail on memory-constrained devices.
H.265 is especially slow in this WebAssembly environment and is most practical for short clips.
Available memory and sharing features vary by browser and device.

Frequently asked questions

Is my video uploaded to a server?

No. The selected video and compressed result are processed in the browser and are not uploaded to Browser Kitty.

Which codec should I choose?

H.264 is the best default for compatibility and practical browser-side processing time.

How long does compression take?

It varies widely with duration, resolution, codec, and device performance. Long clips and H.265 can be particularly slow, so testing with a short clip first is recommended.

Can I remove the audio track?

Yes. Enable audio removal to create a video without its audio track.

Offline version and source code

The root-level video-compressor.html on GitHub is an expanded single HTML file with FFmpeg / WebAssembly bundled inside. You can download and open it directly in a browser, and video processing runs locally on the device.

View source on GitHub

Use together

Useful next steps and companion tools, organized around the workflow.