How to use this tool
We've designed this interface to be as simple or as powerful as you need it to be. Whether you just want to shrink a video for Discord or remaster audio frequencies, here is how to navigate the workflow.
1. The Basics
Upload your file and select a Preset from the dropdown. This is the fastest way to get results. We have presets for "Web Optimized" (small size), "High Quality," and "Audio Extraction."
2. Fine Tuning
Use the tabs to adjust specific settings. You can change the CRF (quality vs size), strip audio tracks, or apply visual filters like brightness and contrast without needing to know complex code.
3. Power Users
Check the "Options" tab. You can inject raw FFmpeg flags (like -map 0 or metadata changes) directly into the command generator.
4. Conversion
Hit convert. The first time you run it, the browser needs to download the conversion engine (approx 30MB). Subsequent conversions will be instant.
Supported Formats & Codecs
Because this is running purely in JavaScript/WASM, we support the most common web-friendly formats.
- Input Containers: Just about anything. MP4, MKV, MOV, AVI, WEBM, FLV, WAV, MP3.
- Output Video: H.264 (MP4), VP9 (WebM), and GIF.
- Output Audio: AAC, MP3, Opus, and WAV.
Performance & Limitations
Since we aren't using a supercomputer in the cloud, the performance relies entirely on your device.
Tip: If you are on a mobile device or a laptop with battery saver on, large 4K files might take a while or crash the browser tab due to memory limits. For best results, use this tool for clips under 500MB or 1080p resolution.
Troubleshooting
"It says SharedArrayBuffer is not defined"
This usually happens if you are using a very old browser or if strict security
headers aren't active. Try using the latest version of Chrome, Edge, or
Firefox.
"The conversion stuck at 100%"
The browser is likely assembling the file output. For large files, creating
the "Download" link can take a few extra seconds after processing finishes.