Video Compressor

About Video Compressor

Easily reduce the file size of your videos with our Free Online Video Compressor. This tool runs entirely in your web browser using FFmpeg.wasm, meaning your video files are processed directly on your device and never uploaded to any server, ensuring your privacy.

Upload your video, choose the desired compression quality using the slider (lower values mean higher quality and larger file size), and click 'Compress Video'. You can preview the original and compressed videos side-by-side and see how much the file size was reduced before downloading.

Features:

• Secure & Private: Compression happens in your browser using FFmpeg.wasm. No files are uploaded.
• Adjustable Quality: Control the trade-off between file size and visual quality using the Constant Rate Factor (CRF) slider.
• Wide Format Support: Handles common video formats like MP4, WEBM, MOV, AVI (browser/FFmpeg dependent).
• Audio Preservation: Keeps the original audio track intact by default.
• Dual Preview: Compare the original video with the compressed result.
• Size Reduction Info: Clearly shows the original size, compressed size, and the percentage saved.
• Easy Download: Download the compressed video directly (output as MP4).
• Progress Tracking: Monitor the compression process with real-time feedback.
• Free to Use: No limits or watermarks.

How to Use:

1. Load Engine: Wait for the video processing engine (FFmpeg) to load (progress bar shown).
2. Upload Video: Drag and drop your video file or click "Select Video".
3. Preview Original: Your uploaded video will appear in the "Original Video" preview. File details are shown below it.
4. Choose Quality: Adjust the "Compression Quality (CRF)" slider. Lower values (e.g., 18) mean higher quality and less compression. Higher values (e.g., 28) mean lower quality and more compression. A value around 23 is often a good balance.
5. Compress: Click the "Compress Video" button.
6. Wait & Preview: Watch the progress bar. Once complete, the compressed video will appear in the "Compressed Video Preview" player, along with file size details. Errors will be shown in the status area.
7. Download: Click the "Download Compressed Video" button to save the result.
8. Share (Optional): Click "Share Tool" to share the tool's link.

Note: Video compression is CPU-intensive and happens entirely in your browser. Compressing large or long videos may take significant time and use considerable system resources (CPU/Memory).

Quick Answer

To compress a video online, upload it here, set the CRF quality slider (18 = high quality and larger file, 23 = balanced, 28 = small file with visible softening), click Compress Video, and download the smaller MP4. CRF stands for Constant Rate Factor: it tells the H.264 encoder how much quality to keep rather than fixing a bitrate, so simple scenes get small automatically and detailed scenes get the bits they need. Typical savings are 40–80 % of the original size. Everything runs in your browser through FFmpeg.wasm, so nothing is uploaded, there is no watermark and no account is needed.

Common Use Cases

Getting under an email or messaging attachment limit

Gmail caps attachments at 25 MB and most chat apps are stricter. Dropping the CRF a few points is usually enough to squeeze a clip under the limit without cropping or trimming it.

Speeding up website and app load times

A smaller hero or product video means faster page loads, less bandwidth billed, and better Core Web Vitals scores.

Meeting upload limits on forums, learning platforms and job portals

Many upload forms cap videos at 100 or 200 MB. Compressing preserves the whole clip instead of forcing you to cut it short.

Freeing up phone and drive storage

Phone video is recorded at very high bitrates. Re-encoding an archive of family clips at CRF 24–26 typically halves the space they take with little visible difference.

Preparing footage for upload to YouTube or social platforms

Those platforms re-encode everything anyway, so uploading a sensibly compressed file saves your upload time without changing what viewers finally see.

Frequently Asked Questions

How do I reduce the file size of a video?

Upload the video to this page, move the CRF slider to a higher number to compress harder, and click Compress Video. The tool re-encodes the clip with H.264 at that quality target and shows you the original size, the new size and the percentage saved before you download.

What is CRF and which value should I use?

CRF (Constant Rate Factor) sets a constant perceived quality instead of a constant bitrate. The scale runs roughly from 18 to 28 for practical use: 18 is visually near-lossless, 23 is the usual default and looks fine for most content, and 28 produces a much smaller file with softening visible on detailed footage. Each increase of about 6 roughly halves the file size.

Will compressing lose quality?

Yes, H.264 compression is lossy by definition, but at CRF 20-23 the loss is very hard to see at normal viewing sizes. Because the source is re-encoded, you should always compress from the original file rather than from an already-compressed copy.

Is my video uploaded to a server?

No. FFmpeg compiled to WebAssembly runs inside your browser tab, so the file is read from your disk, processed on your own CPU, and written back locally. No video data reaches miniwebtool or any third party.

Why is compression so slow?

Compression re-encodes every single frame, which is by far the most CPU-intensive video operation, and it runs on a single browser tab rather than on a server farm. Expect roughly real time or slower for HD footage. Muting, trimming or scaling the clip down first will speed it up considerably.

Is the audio kept?

Yes, the original audio track is preserved. If you do not need it, removing the audio first will shrink the file a little further and make compression faster.

How much smaller will my file get?

It depends on the source. Footage straight off a phone or camera is usually recorded at a wasteful bitrate and can drop by 60-80 %. A file that has already been compressed, for example a YouTube download, has much less room left and may only shrink by 10-30 %.

What is the maximum file size I can compress?

There is no fixed limit, but the browser has to hold the input and output in memory. On a desktop, files up to a few hundred megabytes are usually fine; on a phone, keep it well under that and close other tabs. If a large file fails, split it into parts, compress each, and merge them again.

Is there a watermark or a sign-up?

No. The tool is free, needs no account, and adds nothing to your video.

Related Tools

• Video Bitrate Calculator — Work out the bitrate you need to hit a target file size.
• Remove Audio from Video — Strip the soundtrack to save extra space.
• Video Cropper — Cut away unused parts of the frame before compressing.
• Video Splitter — Break a long video into smaller pieces.
• Adjust Video Speed — Shorten a clip by speeding it up.

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