Online Video Compressor

Online Video Compressor — Shrink Video Size While Keeping Quality

Online Video Compressor is a free, browser-based video compression tool that requires no software installation and no file uploads to any server. Powered by FFmpeg compiled to WebAssembly, it processes your videos entirely on your local device, ensuring complete privacy and data security.

Supported Formats

The tool supports a wide range of popular video formats including MP4, MOV, AVI, MKV, WebM, FLV, WMV, TS, M2TS, M4V, 3GP, and OGV. Whether your video comes from a smartphone, camera, or screen recorder, you can import and compress multiple files at once.

Three Compression Modes for Every Use Case

• Quality Mode: Uses the CRF (Constant Rate Factor) parameter to balance output quality and file size. Drag the slider to choose between high quality and maximum compression. Ideal for archiving, sharing personal videos, or any scenario where visual quality matters.
• Size Mode: Enter a target file size in MB and the tool automatically calculates the optimal bitrate using professional 2-pass encoding. Output size is kept close to the target (±10% variance is normal). Great for email attachments, platform upload limits, or social media requirements.
• Fast Mode: Prioritizes speed by copying the video stream directly where possible, significantly reducing processing time. Best for quick size reduction when top-tier quality isn't a priority.

Additional Parameters

Beyond the compression mode, the tool offers several adjustable options:

• Resolution Scaling: Keep the original resolution or downscale to 4K, 1080p, 720p, 480p, or 360p.
• Frame Rate: Choose from 60, 30, 24, or 15 fps, or keep the original. Lowering the frame rate can significantly reduce file size.
• Output Format: Convert to MP4, WebM, MOV, or MKV to ensure compatibility with different platforms and devices.
• Audio Handling: Keep and re-encode audio, copy the original audio track without re-encoding, or remove audio entirely.

How to Use

1. Click the upload area or drag one or more video files onto the page.
2. Select a compression mode and adjust the parameters in the settings panel.
3. Click "Start Compression." A progress bar will show real-time status for each file.
4. When done, preview each result, download files individually, or download all as a ZIP archive.

Frequently Asked Questions

Are my video files uploaded to a server?

No. This tool runs entirely in your browser. Your video data never leaves your device, so your privacy is fully protected.

Will the video quality drop after compression?

Video compression is inherently lossy, but quality loss depends on your settings. In Quality Mode with the slider set above 75, the difference is usually imperceptible to the human eye while still achieving meaningful file size reduction.

How accurate is Size Mode?

Size Mode uses 2-pass encoding to target your specified file size as closely as possible. Output is typically within ±10% of the target, with accuracy varying based on video content complexity.

Why is the compressed file larger than the original?

This can happen when the original video has a very low bitrate or when the quality setting is higher than the source quality. Try lowering the quality slider or setting a smaller target size.

Can I compress multiple videos at once?

Yes. Drag in as many files as needed and the tool will process them sequentially. All results can be downloaded individually or packaged into a single ZIP file.