Encode settings
Transcode
Convert Video
Browser-side FFmpeg.wasm: codecs, filters, trim, and rate control.
Quick presets
Drop a video or click to browse
MP4, WebM, MOV, MKV, processed locally
About this tool
The Convert tool re-encodes your video using FFmpeg WebAssembly running entirely in your browser. Choose your output format, codec, resolution, frame rate, and quality settings. No file is uploaded — everything happens locally on your device.
Guide & tips
- CRF (Constant Rate Factor) controls quality: lower values mean higher quality and larger files. CRF 18 is visually lossless; CRF 28 is the maximum that still looks acceptable for most content.
- H.264 (libx264) is the safest choice for compatibility — it plays on every device and browser. Use H.265 for smaller files if your target device supports it.
- VP9 in a WebM container produces files 30–50% smaller than H.264 at the same quality, making it ideal for web delivery.
- The "Compress for…" presets in the Quick Presets bar auto-configure CRF, resolution, and codec for WhatsApp, Instagram, YouTube, Discord, and email.
- Use the output size estimator to check the expected file size before starting a long encode.
- For lossless audio, set the audio codec to Stream Copy. This skips audio re-encoding entirely.
Frequently asked questions
MP4 (H.264 or H.265), WebM (VP8 or VP9), MKV (any codec), MOV, and animated GIF. For GIF, the tool performs a two-pass palette encode for the best colour accuracy.
Use the "WhatsApp" quick preset, or manually select 480p resolution, CRF 28, and the "fast" encoding preset. The output size estimator will show the expected file size. A 2-minute clip usually lands well under 16 MB.
FFmpeg runs in single-threaded WebAssembly in the browser. It is slower than a native desktop app but avoids any upload or server dependency. An encoding preset of "fast" or "veryfast" significantly speeds things up at a small quality cost.
CRF (Constant Rate Factor) targets a consistent visual quality across the whole video — the bitrate varies per scene. Bitrate mode targets a fixed data rate regardless of scene complexity. For most uses CRF gives a better quality/size balance.