Frequently Asked Questions
Everything you need to know about VideoReduce.com, WebAssembly technology, formats, and platform limits.
Privacy & Zero Server Uploads
How does VideoReduce.com process videos without uploading them to a server?
We compiled the entire FFmpeg multimedia framework into WebAssembly (Wasm). When you select a video, your browser loads the binary into an isolated Web Worker thread, processing frames in your device's local memory (RAM). Zero bytes are transmitted to any external server.
Can anyone on the internet access my processed files?
No. Since files never leave your device, there is zero risk of cloud data breaches, third-party inspection, or unauthorized storage.
What happens to the video after I finish compressing?
The temporary virtual memory buffer is immediately wiped when you reset the tool or close the browser tab.
Video Compression & Quality
What is Constant Rate Factor (CRF) and how does it prevent quality loss?
CRF is an intelligent rate control mechanism in H.264 video encoding. It allocates more bits to high-action motion scenes and compresses static backgrounds more heavily, resulting in human-lossless visual quality at 50%–70% smaller file sizes.
How do I compress a video specifically for WhatsApp (16MB limit)?
Use our dedicated WhatsApp Video Compressor (/compress/whatsapp-video) or select the '70% Smaller' preset with 720p resolution on the homepage compressor.
How do I compress a video for Discord (25MB limit)?
Select our Discord Video Compressor (/compress/discord-video) or enter '24 MB' in the Custom Target Size box to guarantee smooth in-chat video embed playback.
Format & Codec Support
Which video and audio formats are supported?
We support MP4, MOV (Apple QuickTime), MKV (Matroska), WebM (Google VP8/VP9), AVI, FLV, GIF, MP3, AAC, and lossless studio WAV (16-bit PCM).
Can I convert iPhone MOV videos to MP4?
Yes! Use our MOV to MP4 Converter (/convert/mov-to-mp4) to convert Apple QuickTime recordings into universal H.264 MP4 videos compatible with Windows and Android.
Devices, PWA & Commercial Use
Can I install VideoReduce.com as an app on my phone or computer?
Yes! VideoReduce.com is a certified Progressive Web App (PWA). Click 'Install App' in the navbar or use 'Add to Home Screen' in iOS Safari / Android Chrome to install it natively.
Is VideoReduce.com free for commercial use?
Yes. VideoReduce.com is provided free of charge for both personal and commercial use without watermarks or account signups.
Still Have Questions?
Our engineering team is here to assist with custom codec parameters, bug reports, and partnership inquiries.
Contact Support Team