RaahUPSC · Video Tools
Compress Video
Cut a large recording down to a size you can email, upload to a portal or send on WhatsApp. The tool re-encodes to H.264 MP4 and tells you exactly how much smaller the result is.
✓ No upload · ✓ No sign-up · ✓ No watermark
How to use Compress Video
- Choose one or more videos (MP4, MOV, MKV, AVI, WebM, M4V, 3GP, FLV or WMV); several files share the same settings and can be downloaded as a ZIP.
- Move the Compression slider between 18 and 40. The default is 28; every step up trims more off the file at some cost in detail.
- Pick a Max height (Keep, 1080p, 720p, 480p or 360p) and an Audio setting: 128, 96 or 64 kbps AAC, or Remove audio.
- Press Compress and watch the percentage. When it finishes you see the before and after size, then download the MP4 (or a ZIP for several files).
What the compression slider actually changes
The slider is the x264 CRF value. CRF holds visual quality roughly constant and lets the bitrate drop wherever the picture is simple, so a talking-head lecture shrinks far more than a fast sports clip. Around 23 looks near-identical to most sources, 28 is a sensible balance, and above 32 smearing becomes visible.
Resolution usually saves more than CRF: 720p on a 4K phone clip quarters the pixels. The height cap uses a min() rule, so a 480p source is never enlarged. Audio becomes AAC, where 64 kbps is plenty for speech, and the MP4 gets faststart so it plays before fully downloading.
Limitations
- Every file is fully re-encoded, which is slow on phones; a ten-minute 1080p clip can take many minutes even on a laptop. Output is always H.264/AAC MP4.
- A video that was already heavily compressed may come out the same size or larger. The tool tells you when that happens; raise the slider or lower the height.
Frequently asked questions
What setting should I use to get under a portal's size limit?
Start with 720p and the default 28. If it is still too big, try 480p or a value of 32, and use 64 kbps audio for speech.
Why did my compressed file get bigger?
Low-bitrate sources such as WhatsApp forwards are already squeezed, and re-encoding them can spend more bits than the original. Raise the compression value or lower the height.
Does my video leave my computer?
No. FFmpeg runs as WebAssembly in your tab, so the file is read and encoded locally. Only the engine itself is downloaded, once.