Audio & video / Local FFmpeg tool
Merge Two Videos
Join exactly two compatible video clips in sequence and export one MP4.
The first run loads an approximately 31 MB FFmpeg WebAssembly core from this site. It does not use a CDN or upload your files.
Files are limited to 200 MB total and 20 minutes; mobile devices use an 80 MB limit. Reverse, GIF and boomerang tools have lower duration caps.
At most 60 download files are generated.
Processed result
The first run loads an approximately 31 MB FFmpeg WebAssembly core from this site. It does not use a CDN or upload your files.Validated downloads will appear here after processing.
Local AI / Speech to text
Transcribe the current audio or video
Open-source Whisper Tiny runs in your browser. The file, audio and result are never uploaded.
Choose an audio or video file in the workbench above first.
◎ The model loads only from 321Kit; MiniMax is not called and no transcript history is stored.
Transcript
How it works
Merge Two Videos
Both inputs are decoded and concatenated through matched video and audio filter chains.
How does this tool process my file?
Both inputs are decoded and concatenated through matched video and audio filter chains. Processing uses single-thread FFmpeg.wasm. The page does not upload, store or inspect file content outside this device. Cancel, error and page close terminate the worker and revoke temporary object URLs.
What limits apply to the output?
Both clips must include audio and have the same width and height. Files are limited to 200 MB total and 20 minutes; mobile devices use an 80 MB limit. Reverse, GIF and boomerang tools have lower duration caps.
Anonymous feedback
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