Audio & video / Local FFmpeg tool
Audio to Opus Converter
Encode speech or music to efficient Opus audio in an OGG container.
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 to Opus Converter
Opus is optimized for a wide range of bitrates and works especially well for speech.
How does this tool process my file?
Opus is optimized for a wide range of bitrates and works especially well for speech. 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?
Output is .opus using the libopus encoder and OGG framing. 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?
Found a problem or an idea to make this tool better? Tell us. We review every report and start working on actionable improvements within 2 days, continuously improving reliability and usability.