How Adapterry Works
Adapterry does all of its video work inside your browser tab, on your own device. Here is what that means, in plain words.
Your computer does the work
When you open Adapterry, your browser downloads a video engine called FFmpeg. It's the same open source tool many video apps use behind the scenes. Your browser runs it on your own device, and your videos are read straight from your disk.
WebAssembly, in plain words
WebAssembly is a way for websites to run fast, app-like programs inside the browser. It lets FFmpeg, which normally has to be installed, run in a tab with nothing to install. It can only read the files you choose to add.
The fast path
If all your clips use H.264 video and AAC audio with the same resolution, frame rate and audio settings, Adapterry joins them without re-encoding. This is typical for clips from the same phone or camera. It's quick and keeps the original quality.
Full conversion
When clips don't match, for example AVI files, VOB files or videos from different devices, Adapterry re-encodes everything to H.264 (CRF 23, veryfast preset) and AAC at 128 kbps, 48 kHz stereo.
The output takes the first clip's resolution, capped at 1920x1080, and the frame rate is capped at 60 fps. Clips with a different shape get black bars instead of being stretched, and clips with no sound get silent audio so the join works.
Time and memory
Because your device does the work, speed depends on your hardware. Large files can take several minutes, and the tab needs to stay open until the MP4 is ready.
There is no fixed file size limit, but your device's memory sets the ceiling. Jobs of several GB run best on a desktop computer with plenty of free memory in Chrome or Edge. Phones handle smaller clips. If the browser runs out of memory, you'll see a message with ways to fix it.
Works offline
Once the page and the video engine have loaded, you can disconnect from the internet and keep processing videos.
Questions and answers
Does Adapterry use a server to convert my video?
No. The server delivers the page and the video engine to your browser. The conversion itself runs on your device, and your videos stay there.
Why is the first load slower?
The video engine has to download the first time you use it. Your browser may keep it cached, so later visits can start faster.
How can I tell if my files will take the fast path?
Clips from the same phone or camera, saved as H.264 with AAC, usually do. Mixed sources, AVI files and VOB files always go through full conversion.
What should I do if I see an out of memory message?
Try fewer or shorter videos, close other browser tabs, or switch to Chrome or Edge on a desktop computer.