Audio & video / Local FFmpeg tool
Audio Sample Rate Converter
Resample audio to 22.05, 44.1 or 48 kHz and export MP3.
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
Audio Sample Rate Converter
Resampling changes the number of samples per second; it cannot recreate frequencies missing from the source.
How does this tool process my file?
Resampling changes the number of samples per second; it cannot recreate frequencies missing from the source. 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?
Choose the rate required by your playback or editing target. 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
Did this tool solve the job?
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