How it works
PlanetVid runs FFmpeg compiled to WebAssembly inside your browser tab. The engine (~30 MB) is fetched once on your first conversion and cached; after that the converter also works offline. Because everything is local, a private video stays private - there is no upload queue, no server and no watermark.
How to convert a video
- Drop your video on the page or click to pick a file (MP4, MOV, MKV, AVI, WebM and most other formats are accepted).
- Choose the output format: MP4 for maximum compatibility, WebM/MKV/MOV for other targets, GIF or animated WebP for short animations, MP3/M4A/OGG/Opus/FLAC/WAV to keep only the audio.
- Optionally pick a resolution and frame rate, set quality and audio bitrate, rotate, change playback speed, trim with a start time and duration, or remove the audio.
- Hit Convert and watch the progress bar - then preview the result and download it.
Tips
- Conversion speed depends on your CPU - a browser can't use your GPU for encoding, so long 4K videos take a while. Trimming first or picking 720p speeds things up a lot.
- GIFs get huge fast. Keep them under ~10 seconds, 480p and 12 fps for shareable file sizes.
- Audio extraction is fast - pulling an MP3 out of a video takes seconds since only the audio stream is re-encoded.
FAQ
Is there a file size limit?
There is no artificial limit. The practical ceiling is your device's memory - files up to a few hundred MB are usually fine on a desktop.
Why does my very first conversion take longer?
The FFmpeg WebAssembly engine downloads once (about 30 MB) and is then cached by your browser, so later conversions start instantly.
Does it work on mobile?
Yes, in modern mobile browsers - but conversion is CPU-heavy, so short clips are recommended on phones.
Is anything watermarked or tracked?
No watermark, no account, no upload. The output file is bit-for-bit what FFmpeg produced on your device.