Steps
- Choose one audio file from this device.
- Select 22,050 Hz, 44,100 Hz or 48,000 Hz.
- Choose the MP3 bitrate for the exported file.
- Process locally, verify playback and download the result.
Audio & video / Local FFmpeg tool
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.
Validated downloads will appear here after processing.
Practical guide
Sample-rate conversion changes how many samples are written per second. Use the rate required by the destination editor, player or delivery specification instead of choosing the largest number automatically.
Resample audio to 22.05, 44.1 or 48 kHz and export MP3.
Audio file: sample-1.wav
Sample rate = 48,000 Hz
Audio bitrate = 192 kbps — balanced Expected result Creates a probed and validated .mp3 (audio/mpeg). Actual method: Resampling changes the number of samples per second; it cannot recreate frequencies missing from the source. Output boundary: Choose the rate required by your playback or editing target.
Choose Audio file sample-1.wav and first confirm that each required audio stream exists.
Use Sample rate = 48,000 Hz; Audio bitrate = 192 kbps — balanced. The actual FFmpeg rule is: Resampling changes the number of samples per second; it cannot recreate frequencies missing from the source.
A download appears only after duration, stream type and .mp3 container validation. Also check this boundary: Choose the rate required by your playback or editing target.
Local AI / Speech to text
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.
How it works
Resampling changes the number of samples per second; it cannot recreate frequencies missing from the source.
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.
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
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